As much as we love these Cougars, nothing’s perfect. It’s a fact of life that we must all do a little maintenance work at one time or another on our cars. Some things, however, are common problems inherent with this body style, and this section deals with repairing them.
Please keep in mind that the observations given here are simply the culmination of personal experience, professional advice, and shared common knowledge. When in doubt, it is always best that you seek your own professional advice or at least get a second opinion. We claim no responsibility for the accuracy of the information herein.
Dash Lights/Radio Inoperative
First and foremost: Make sure that all the light bulbs didn’t burn out of the dash (including the two in the speedometer module and the two in the radio, if necessary). We know, its common sense, but you might want to check it out anyway. This requires removing the cluster, or at least taking it out of the dash far enough to get your hand back there. For cars with column shifters, be careful of the gear indicator cable on the bottom of the cluster—that can easily get bent or broken if you’re not careful. There are 4 T-20 Torx bolts in each corner of the cluster—remove them, and it’s essentially loose. If you need to remove the whole cluster, you must uncouple the wiring harness(es) on the back of the cluster. Squeeze both sides of the harness at once, and just pull out.
Second, you could have a bad fuse or circuit breaker. We’ve had that happen before, and it drives you nuts until you discover that out. Over time, circuit breakers and fuses can wear out just like any other mechanical part. Since there’s always power going through them, day or night, it makes sense. That’s a cheap fix and you can have the questionable parties tested if necessary.
Third, one or both of your wiring harnesses for the dash cluster could be loose. That’s kind of uncommon but well within the realm of possibility. And it’s a free fix.
Fourth, be sure to inspect your ignition switch. When the switch or its associated wiring goes bad, all sorts of strange things can happen with the electric portions of the dash. This could potentially be a dangerous situation so be sure to inspect or change the switch as soon as you have this issue. Be sure to also inspect the wiring going to the switch, as it can get brittle and move over time, causing heat and melting of the harness and/or wiring.
Fifth (and probably most important): Have you installed a radio lately, or removed and replaced the stock one? If so, that could very well be the cause of your problem. The wiring behind the radio can get pinched very easily due to its proximity to the back of the radio. The main culprit is a light blue wire with a red stripe; that’s the one on the same circuit for the dash lights. It’s for the light in the radio, clock, and lighter panel/ash tray. When that wire gets pinched, it causes a short in the system, and since the dash lights are on that same circuit….no more dash lights. Even worse, if the fuse doesn’t blow, then you’ve got power overload running through the car, and the common gateway is the headlight switch. This can cause electrical feedback into the switch and make it smolder, spark, or burn. It’s no fun to have a headlight switch burn up on you halfway to work.
How to solve it? You must find out for sure if that wire’s getting pinched. (There’s another wire that can also cause the same problem—light green with a yellow stripe). Best thing to do is remove the radio and start moving wires out of its way. If you try in vain to wiggle wires around and still can’t solve the problem, then there’s the last resort: tracing the wires back to the fuse box, cutting both, and hooking up only the one that goes to the dash lights. The fuses you’d look for are either the #5 (15A, light blue) or the #13 (5A, tan) positions (please refer to this pagefor a full fuse panel reference guide). That should solve the problem once and for all, but it’s only recommended as a last resort. That should get you back to getting normal dash lights, and your flashlight can safely reside in the glove box again.
Gauges Act Erratically
First off, if you have not changed the ignition switch, that would be the first place to check for issues. A bad ignition switch, or faulty wiring to the switch, will cause a lot of issues to occur with the car, including intermittent charging and drivability problems, but usually one of the first indicators is that the gauges will do abnormal things every once in a while. Please have this inspected and changed first. If you find that the wiring is indeed melted, Fox Resto sells a very inexpensive ignition switch repair kit to do the job properly.
It’s also important to note that the oil, temp, amp and fuel gauges run off 5 volts, not 12. There is an instrument voltage regulator (IVR) that is on the backside of the cluster, and its job is to reduce the 12v power coming in down to 5v. It’s similar to a 9v battery; in fact, it snaps right on just like one. Ford’s been using that same part since 1971 so it used to be a common part at any Ford dealer (p/n D1AZ-10804-A) and it could be the source of your problem. Be aware that it’s sometimes very difficult to find this part lately, even at parts stores, but CJ Pony Parts does carry a version that works for our cars. Otherwise you may end up scouring eBay or even a salvage yard to find one from another cluster. You can find instructions on replacing the IVR on YouTube here.
The direct signal to each gauge comes from a sending unit found around the car or on the engine block at various locations. The temp gauge relies upon the temperature sensor (top of the intake manifold); the fuel gauge depends upon the fuel sending unit (inside the gas tank); the amp gauge/light works via the ammeter (hardwired inline); and the oil gauge/light works from the oil pressure sending unit (from the block, around the oil filter area). Now obviously there’s a wire running from each sensor to its corresponding gauge. Normally the problem is that the sending unit itself has gone bad due to age and normal usage. Or, perhaps it’s that the wire is usually in close proximity to the motor, and if the wires get hot enough over time, the casing can melt or rub through and touch metal…giving you haywire readings. Those are your first places to look for trouble. You can remove the suspected unit and check it for corrosion, and also check the wiring. On the 5.0L V8 engines, the wire running to the oil pressure sending unit just loves to get all tangled up around the a/c and power steering brackets. And the 3.8L V6 can throw a temperature sensor in a heartbeat. So if your light comes on (or your gauge goes all the way to HOT) when you know that the car isn’t that warm just yet, that’s a good place to start. The sensors themselves are not very expensive, and you might even want to replace them every few years as part of routine maintenance. To test the gauge in question, remove the wire from the sending unit, start the car, and momentarily ground the wire, then reconnect. If the gauge moves at all, the sending unit is probably bad. If it doesn’t move, then the gauge is bad.
If you’ve checked the wiring and gauges, then the next place to look is the alternator area. It’s possible that you have a bad voltage regulator, and that would definitely affect your gauges almost instantly. They also go bad with time and usage, and are not usually a problem to find or replace. But while you’re there, be sure to inspect the wiring going to the alternator itself. Notice that the wires are of a heavier gauge; that’s due to the heat and voltage load that the wires have to endure every time you drive the car. Now those wires can break loose from brittleness, or pull away, or rub against metal, or arc electricity over to the block….get the picture? And your gauges will reflect this abnormal behavior. This is a SERIOUS and POTENTIALLY DANGEROUS situation! In fact, when you buy a new or remanufactured alternator, there is sometimes a new wiring harness included for the alternator that you MUST install. There have been fires under the hoods of Ford autos with bad alternator wiring. So please inspect the wiring as soon as you can, and if you do get a new alternator, either install the new wiring yourself or have a shop do it for you. No matter the expense…it’s worth it to save your car from a potential disaster.
If this still hasn’t helped then you must look to the rest of the ignition system: the starter solenoid, distributor cap/rotor, spark plugs/wires, or your even battery itself can cause the gauges to work erratically. Obviously if you have an amp gauge, you should notice the level drop (or the light will come on if you have a light); that indicates a big time problem somewhere—be sure to have it checked out ASAP. And, if all else fails, you go right back to Point A: the gauges themselves. Now they are usually pretty reliable, but they can conk out on you. It’s usually best to check them last though, just to make sure the rest of the system is operating correctly.
So what about the speedometer and tachometer? Well, the 1983-84 Cougars have a traditional speedometer cable that attaches to the transmission housing. If the cable squeaks really loudly and consistently, there could be a lack of lubrication or even a faulty speedometer head (gauge), but usually that indicates that the cable should be replaced.
Beginning in 1985, all Cougars have electronic speedometers. That’s right, no cable; the signal is sent to the computer (again, via a sensor on the transmission called the vehicle speed sensor, or VSS), and it in turn sends the information to the speedometer. The Cougars and Thunderbirds were actually one of the few Fords in the mid-80’s to have electronically-fed speedos. So when the needle (or digital numbers) start to go wonky, the speedometer sensor on the transmission housing is the place to start.
The wiring is held on by one lonely little 11mm bolt; once removed, there’s a small colored gear on the end that goes inside the transmission casing. It’s called the speedometer driven gear(NOT the drive gear, which is internal) and the teeth can wear out, especially if you have a gear in an automatic transmission with over 21 teeth. Now you’ll need to take the gear off the VSS (one clip, very simple) and take it to the Ford dealer, where you can purchase/order a new one, or you can look for one online. Also, it could be a bad VSS unit; that’s known to happen with higher-mileage cars. Fortunately it’s cheap and should definitely help the situation. Again, keep in mind that the VSS is a direct hot line to the computer.
Now if the gear’s not bad, and the VSS isn’t bad, then your gauge has just gone on you. It’s a fairly expensive fix at a speedometer shop but you might be able to get one at the salvage yard. Now the digital speedos are a real nightmare. They’re designed to be tamper-proof…so that means they’re not meant to be fixed by a do-it-yourselfer. You either have to have it repaired professionally or force yourself to get another cluster and use it, with its incorrect odometer and all. No way to reset that either. The 1985-88 analog speedos (XR7’s and V8 sport models) are more traditional in design and will allow replacement or repair as necessary. If you suspect that you need your speedometer fixed, you can always use a search engine for a list of shops. They can usually give you a price quote over the phone or via e-mail.
The tachometers are also electronic. They run off the signal from the ignition coil, by the strut tower nearest the battery (dark green wire with the white stripe). If you happen to have bad wiring then the tach signal can go erratic. But the biggest offender to a bad tach reading is a faulty wire running from the coil to the distributor cap…you know, the spark plug wire-looking wire. If you have the original or an old wire that could be your problem.
As you can see, the causes for erratic gauge behavior are plentiful. Whenever you start to deal with electricity on a Ford vehicle, you’re in for a real treat, so be prepared for the worst and hopefully you’ll come out on top very quickly. Remember, the gauges are the windows to the inner workings of your car, whether intentional or faulty.
Fuel Gauge Stops Working
In the meantime, you can use your trip odometer to calculate your gas mileage. For V6 and V8 cars, you should have about 1/4 tank at 225-275 miles. For the turbo-4 XR7, you have a smaller gas tank (18 gallons vs. 22 gallonsfor the V6/V8) but you also get better gas mileage, so you can go to about 300 miles with 1/4 tank left. It’s not perfect but this will generally work well until you get the sending unit changed.
By all means, if you have any qualms about tackling this job yourself, DON’T do it. Take it to a shop and pay the money; it’s worth every cent for you not having to mess with it.
If you are going to change the sending unit yourself, though, here’s some info you’ll need to know.
– When getting a new sending unit, be sure to specify whether you have an electronic or analog gas gauge. There is definitely a difference between the two, and if you end up getting the wrong one, your gauge will work the opposite of normal.
– The resistance for fuel level sending units for our cars is as follows:
Analog: 60-86 ohms empty, 8-12 ohms full
Electronic: 10 ohms empty, 160 ohms full
– It is possible to have your stock sending unit rebuilt. Check your local shops to see if they offer this service; if not, a quick search engine query should help you out. You may need to send it away, and it will take some time to get the unit back, so plan accordingly.
SERVICE Reminder Light on Digital Speedometer
To remove the SERVICE reminder, simply press the TRIP and TRIP RESET buttons simultaneously and hold for a few seconds, until you hear 3 beeps. The SERVICE reminder will then go out.
If you have just an S in a circle on the speedometer display, that indicates a replacement speedometer module. More information about removing the S warning can be found here.
One of the first signs of a problem with the ATC system is the flashing display. The head unit (where you push the buttons) does a self-diagnostic as it’s running. If it finds an actuator fault it will flash the display. Fortunately you can test the unit and get the error code yourself:
- Make sure the car is sufficiently warm, at least 50 degrees F (10 degrees C).
- Push OFF/AUTO and DEFROST at the same time, then press A/C within 2 seconds.
- The code will display. This self-test will stop all normal functions of the ATC unit.
- Exit the self test by pressing the COOL button.
When you get the code, compare it to this chart:
ATC Error Code
Blend door actuator out of position.
Floor/Panel actuator out of position.
Panel/Defrost out of position.
Outside air/recirculation actuator out of position.
Blend actuator over current.
Floor/Panel actuator over current.
Panel/Defrost actuator over current.
Outside air/recirculation actuator over current.
No faults found in self-test.
If this appears with any other code, ignore it. If it appears alone, it’s the same as code 88.
Clutch signal low.
Sensor string open (NOTE: if the interior of the car is very cold this error may appear. Try warming up the car, shut off the ignition, restart the car, and enter the self test again).
Sensor string shorted.
Control head unit worn or damaged (unit must be replaced).
Blower signal shorted.
No faults found in self-test.
Now a code 09 or 88 doesn’t necessarily mean that there’s nothing wrong with the system; it simply means that the self-test didn’t find anything wrong. If you are experiencing a problem and you get either of these two codes, then obviously something’s still amiss in the system.
Another problem is getting cold or warm air when you’re not supposed to, or getting air out of vents that aren’t selected on the head unit. These problems are more often associated with an actuator. When the actuators start to die, they won’t fully open or close their respective doors.
If you have no blower motor power at all, try changing the blower controller. This is also a common problem, and changing the controller (or even just the fuse for the controller) usually does the trick.
Now we don’t want to ruin your day, but with a good number of these codes, replacing the ATC head unit is commonly the solution to a problem. You cannot buy a new ATC unit from a Ford dealer, so you’ll need to find one at a salvage yard or via eBay. Physically changing the unit is not really all that bad.
Finally, there are lots of different tests that you can perform (if you’re so inclined) to isolate a problem. There are too many to list here; shop manuals list at least 13 different procedures. A lot of them include measuring voltage between connectors. If you don’t want to mess with this system on your own, about your only choice would be to take the car to a Ford dealer, or to a mechanic that knows a lot about the Ford ATC system. This can be quite an expensive repair so be prepared.
Power Windows Won't Operate
A. The window goes up or down REALLY slow or not at all
B. You have seem to have good power but the window still won’t go down or up
In the case of A, your motor’s contact brushes have probably disintegrated. Over time, this happens to any sweep-contact type of motor (your alternator and voltage regulator are another example of this). So it’s not anyone’s faults except for Father Time and usage; quite a normal thing really. Good news is, you can get the motor rebuilt, or perhaps be able to hunt one down in the salvage yards. Or you can even buy them new at the Ford dealer (beware of sticker shock), through parts stores, or via eBay. Buyer beware, however: we’ve experienced bad new aftermarket motors from eBay.
If you’re the adventurous type and would like to diagnose the problem yourself, here’s how to do it. First, remove the door panel and insulation, and find the wires going to the power window motor. They’re on the bottom, in the hole toward the front of the car, and should be either pink/black or yellow/black in color. Next, determine the power wires—you’ll have two: one to make the window go down, the other for going up. Skin back each wire a bit (usually about 1/2″ is sufficient), and turn the ignition key on but do not start the car. Then you’ll need a 12v battery charger. Touch the 12v positive clamp onto one wire, and the 12v negative on the other wire. (Might have to use trial and error here). Your window should go one way or the other with no problem. Then, do the opposite—touch the 12v positive clamp to the opposite wire and the 12v negative clamp to the remaining wire (reversing polarity). The window should go the other direction smoothly. If all goes as written here, that means with a pure 12 volts going to each direction, your motor is not putting out 12v, and that indicates a rebuild (or replacement) is necessary. Nine times out of ten, this is the culprit. (Be sure to properly tape up the exposed wires before going any further). Now for some reason, the window always seems to go up and down slower than stock after a rebuild. But they can be very inexpensive; we’ve paid as little as $40 for a rebuild. Quite a bargain, especially since you don’t have to risk cutting yourself up.
However, if you want to tackle a motor rebuild yourself, Robert has pass along this information: “I had a different failure and it happened on both windows over time. The motor worked fine but the gears inside had completely broken. When searching for the parts to fix it, I found them labeled on RockAuto.com and at Autozone over the counter under window regulator – Dorman part number 74426. It’s basically a 45-tooth gear with a 9-tooth gear glued to it. The failure occurs when the glue connecting the two gears fails which allows the gears to spin independently of each other and thus the window will not go up and down. I ended up drilling out all the regulator and window glass rivets and removing the entire regulator and the window glass, but in retrospect it might be possible to get to the motor alone without removing and having to reinstall all that. If you do remove the regulator, it is spring loaded so you need a helper, and the motor needs to be reinstalled at the center of the travel (thus the need for a helper again). To change the gear in the motor, remove the motor from the car of regulator by removing three small screws. Then you can open the cap and see the gear that need to be changed. To get it out though, I believe you need also remove the long gear screw. I had done it first so even that might not be necessary. If you do need to, remove the two long bolts that hold the cover on the motor case and pull it out. Once you do that you should be able to remove the gear, clean the broken parts and install the new one. To reinstall the long threaded screw with the armature you need to remove the bottom of the motor case with the brushes too. Just knock it off with a screw driver then reset the springs and brushes, insert the armature, then with your helper again holding the motor case, slide it back over the armature making sure the brushes are properly seated. From there you should be able to install the new replacement gear and reinstall everything. Lots of detail work with little parts, plus tons of drilling and re-riveting if you need to remove the regulator but this is a $15-$25 fix if you can DIY.”
If your problem sounds like B above, better read up…there are many things associated with this area as well. Probably the most common thing is the window glass physically separating from the plastic clip holding it in (1987-88). Again, due to time, the glue gets brittle then lets the glass slip out. Now it may be possible to use some kind of epoxy to reglue the glass back into the clip, but we’ve been told by several people that there’s not much success in doing that. The Ford garages usually just order whole new windows; the clip comes glued on them already. Plus, to reinstall the clip requires a 1/4″ rivet gun, and that’s like a $300 piece! Your best bet would be to call or visit an automotive glass specialist and see if they can help you. They can also order the clips in aluminum now, which is much better and way more reliable. Jason has reported that using Gorilla Glue has worked; it’s been over 2 years with no problems. Several people note that they got special adhesive from glass shops. The key to getting any kind of adhesive to work is to sand the glass in the attachment area, and to thoroughly clean everything with degreaser before applying the cement. If reusing the plastic clips, drilling holes in the plastic seems to help with providing more adhesion.
Dennis has passed along some information about the above window clip problem. “You can tell your viewers not to bother using any over-the-counter adhesives or epoxies, believe me I tried them all. There is no substitute for the glass adhesive that can only be gotten from an auto glass shop. They don’t like to sell it to civilians, because it is extremely toxic and is very bad news if you get any of it on your skin. Once I described my problem to them, they sold it to me. The owner said he repairs 2 or 3 Cougars a month with this problem. Once you have the glue, the job is not bad. The key to success is you have to make sure you get all the old glue off the window before you apply new. The glue cost $8.00 and I’m back in business!”
It’s also possible that the regulator (scissors mechanism) could be bent or binding up on some object inside the door. A loose guide or bent door lock rod would definitely do that. Or it could have simply slipped off the track entirely. Whatever the case, if you’ve got what you feel is good power to the motor itself, then one of these problems are what you’re looking for. If you’re careful enough you can probably fix it yourself with little effort. All it requires is that you remove the inner door panel and insulation, and you’ve got access to almost everything inside the door. A little tip: before you reach your arm inside the door, please remember that the metal is very sharp and WILL cut you up in a heartbeat. An old trick is to slit some rubber hose longways and push it over the metal, then you can work inside the door with ease.
Lastly, you may have a bad window switch. It’s not a common thing to happen, but if you’ve accidentally spilled something down in the area of the switch, it could either prevent good contact or short out the switch. The switch can be wiggled off its base and cleaned, in case you need to check it out.
If all else fails, please see an auto glass place—they’ve run into everything that can possibly happen to auto glass and will have an answer for you.
Power Door Locks Won't Operate
Really, power door locks in our cars run from a pretty simple system. Power from the fuse box is fed through relays (behind the dash on 1983-86 cars, underneath the passenger seat on 1987-88 cars), which is then fed to the switches on either door panel. From there the power is fed to the door lock actuators which are buried inside the door, behind the door panels. Here are some basic procedures for tracking down the problem:
- If you press the door lock button (both the “lock” and “unlock”) and hear the relays clicking in both directions, then the problem is more than likely with the actuator or the switch.
- If you don’t hear the relays clicking, or hear one but not the other, then you have a bad relay.
If a switch or relay change does not solve the problem, you will pretty much have no choice but to remove the door panel and at least test the stock power door lock actuator. The actuator is usually a goldish or silver color with a rubber boot, and is attached to a bracket that is pop-riveted onto the door frame. The hook end of the actuator loops through the door latch mechanism. It’s a pretty tight reach into the area so be careful (and also remember to put your window up first!).
Your first instinct may be to just punch out the pop rivet to remove the actuator, and that’s fine. Upon reinstallation you’ll need to use a bolt, nut and some washers (or another large pop rivet, if you have access to one). However, Jason has passed along this alternate method of removing the actuator: Reach your arm inside the door and grab hold of the actuator. There is a bracket that holds the actuator (you know the one, most of you drilled the rivet to remove it). The actuator has two pins that hold it to the bracket. Twist it, one of the pins will come out of the bracket. Then pop the other side out.
Now that it’s out of the bracket, unhook it from the door latch. The wiring harness simply pulls off from the bottom. Once the hook is off the latch mechanism (just be patient), you can fully remove the actuator from the door. To test it, get the harness from inside the door and plug it back into the actuator. Use your power door lock switch to see if the rod does indeed move up and down. If not, or if you have sporadic success, then you will definitely need to get another actuator.
About that new actuator: if you’re thinking about taking a trip to the Ford dealer to order a new one, you won’t find it listed for a Cougar or Thunderbird. At last check it was available for a Lincoln Mark VII, though. Or you can use a Mustang actuator. Basically most Ford vehicles used the same actuator. The only thing that differs is the rod, with both its length and its end configuration. Some rods have an “S” shape, and some have a “J”-shaped hook. It really all depends on the options your car has (keyless entry, illuminated entry, etc.) as to which type of rod is used. The main goal is to try get a replacement actuator with the same type of rod already installed; however, you can use any actuator and just switch over your rod, if you so wish. There is a keeper lock with ball bearings inside that can be removed to allow rod swapping. It is a little tricky but can be done if you’re patient.
There are some companies, such as A1 Electric, that offer door lock actuator kits with lots of different rod types in the same kit, so that you can create exactly what you need. These kits are probably available on eBay or Amazon as well.
You can always get a used actuator from the boneyard, and that’s okay. Just be aware that you may end up with a bad one, or one that will go bad perhaps sooner than later.
Before you install your new or used door lock actuator, lift up the rubber boot and apply some white lithium grease. This will keep it lubricated for a long time and keep water from infiltrating the mechanism.
Gear Indicator Doesn't Line Up
First thing to do, as usual, is to disconnect the battery. Remove the collar from around the tilt wheel lever, if your car is equipped as such. It simply unsnaps from the left side. Then remove the 5 screws from the bottom of the steering column cover. You may have to remove the trim from the dash directly underneath the column as well. The bottom half of the cover should come off, and then you can begin the adjustment.
You will notice a white plasic collar that is fastened to the actual steering column shaft. There will be a very thin red-colored cable on the left side; that is the cable that goes to the needle on the instrument cluster. On the righthand side is a 7mm screw. This is your adjuster.
ADJUSTING THE INDICATOR
All you need to do is loosen the screw, and turn the collar until the needle lines up, then carefully clamp down the screw. This is a very delicate procedure though. The plastic can very easily snap if you overtighten the screw. And if you ever remove the collar, it can break in half while trying to get it off the column shaft. We recommend that you do this procedure in warm weather, or inside a heated garage if it’s cold outside, in order to get the plastic to a temperature where it won’t break as easily.
If your collar does happen to break, you could use duct tape on it (super glue will not hold). We’ve done it before and it works just fine, although you may need to lube up the column underneath the adjuster to allow the collar to slide easier. Jimmy has also suggested using a simple radiator hose clamp—just open it all the way up and wrap it around.
Should the red cable becomes disconnected for whatever reason, it’s not very fun to fish back over the loop on the collar, so take your time. Now if the cable breaks, Louis has found a solution: “We found a steel cable with small crimps (we think it’s for hanging pictures) in the Walmart fabric department. It works like a charm, and there’s enough cable and crimps to do at least 4 repairs.”
EQ Power Button Fix
However, if you DO want a more professional fix, Shanon offers a solution:
“This repair allows for the use of the stock EQ but please note that once this has been done, it can no longer be turned off.
“If the power button on the EQ does not work, do the following:
1. Remove the EQ from the dash and take it inside or to a place where you can work and not lose parts. You will need a hot glue gun or silicone sealant, a soldering iron, flux, solder, needle nose pliers, standard pliers and various small screwdrivers and a little common sense and ability to solder (minimal experience is necessary, be sure to use the flux on all parts prior to soldering them or the solder will not work.)
2. Disassemble the case of the EQ carefully and take note of how it came apart. You will need to remove the face of the EQ as well. To do this pull on the slide covers until they pop off and remove the Balance knob. Remove the face of the EQ carefully and set all the parts aside. Next remove the nut around the balance knob and pull on the power and “EQ lights” buttons and set them aside. Remove the bottom black plastic cover. This should leave you wtih a piece of electronics equipment that looks very little like what you started with, but this is what must be done. Next, remove the screw on the left side top of the eq and push the side panel away from the body. Next, locate the two white push plugs that secure the top circuit panel to the bottom. After you have unfastened these, open the EQ like a clam shell.
3. Locate the bottom of the POWER switch. Heat the soldering iron and remove the switch by unsoldering the entire 8 pin unit from the circuit board. This takes some patience but it can be done by using a hot soldering iron on the back of the switch and constant pull on the front. Run the iron over the back connectors while pulling on the front. Do this multiple times and eventually you will get it. Next you will need to connect the holes that are left by soldering in between them in pairs of 2. Solder #1 hole to #2 hole, #3 hole to #4 hole and so on. Be sure NO solder gets between the pairs or it won’t work. After this is finished, take the unit to the car and plug it in and make sure it works before reassembling it. If it does not work, check that your soldering job is clean and does not touch any other group. If it does work and it will if you did it right, gut the switch and glue it back up so that it looks right but doesn’t work. Glue it back into the stock location once there is no metal left in it to short out the job. This will allow the EQ to have a stock appearance, though the switch won’t work. Reassemble the unit very methodically until it looks correct and there are no parts left over. Reinstall the unit in the car and enjoy.”
The good news is that, in most cases, the lenses can be salvaged and even repaired. Shawnhas sent this information from his experience:
“My headlights were full of water, yellow, hazy and overall nasty, I used a buffing wheel with some Turtle Wax rubbing compound. It’s pretty gritty and it took most of the haze and yellow out. The compound stuck on the rougher spots so I used it as an indication as where I need to focus more on cleaning. From there I used Meguire’s Cleaning Wax on a new, clean buffing wheel bonnet. I did that until the lights became clear and shiny. From there I used a polish just for temporary protection.
“Since my headlights leaked, I washed them out using Armor-All Car Wash. I put a small amount in the headlight bucks, added some water, then shook them like crazy. Then I stuck the nozzle of the garden hose in the light, turned the headlight upside down so the lens was facing upwards and went full pressure until the suds stopped coming out of the lights. I let them sit and dry in my house overnight and used some tub and tile sealant around the bead of the lights and rubbed it into the seam with a lot of pressure to ensure it filled in the seam. Once that cured I ran a thicker bead of the sealer on top of the previous one and made sure it was even, and let that cure. After that, I wrapped electrical tape around them and reinstalled them.”
So why does this happen anyway? Jim has provided the information below:
Yellowing occurs with a combination of extended nighttime driving, acid rain, and possibly condensation. It mostly occurs on the inside of the lens but can also be found on the outside. The hard plastic used for the lens is susceptible to high heat, and yellowing is a side effect of that.
Since they introduced the plastic lens in 1984 on the Lincoln Mark VII, Ford has used polycarbonate—a high heat resistant, high impact strength plastic that also has low resistance to UV light and moisture. Since headlamp lens light sources generate a lot of heat and require impact resistance, polycarbonate has been the material of choice for all but a couple of GM programs (like the Chevy Berreta/Corsica program, which was an overlay lens—polycarbonate inner/acrylic outer).
As indicated, polycarbonate is very sensitive to UV and moisture. In addition, it is a very soft material when compared to acrylic and even more so when compared to glass. Hence, all polycarbonate headlamp lenses required the application of a UV blocking, silicone or acrylic hard-coat on the surface to provide for some acceptable length of performance. These coatings work much like a sponge and will only absorb so much UV before it starts to get to the base polycarbonate. With time, the surface of the polycarbonate starts to degrade and several things start to happen:
- The substrate starts to micro-fracture/crack which leads to cracks in the protective coating.
- The substrate starts to degrade and changing surface characteristics which leads to haze (fogging) and coating delamination.
- Loss of topcoat leads to significant abrasion.
It should be noted that in spite of these factors, the impact resistance of the degraded lens is still much better than a glass lens. However, you can still get good light from an unbroken glass lens.
Yellowing on the inside may be from various materials outgassing from the inside of the lens. It is also possible that the coating being used on the reflector portion of the lens housing is yellowing. Another possibility is that the light source is emitting UV which is degrading the polycarbonate lens. However, if one can remove this yellowing using solvent, it is probably not the UV attacking the polycarbonate. It may be possible to remove the assembly and pour in some type of detergent to try and dissipate the yellowing. Since you cannot physically get your hand inside the assembly, or even pry it apart, that would probably be about the only thing you can do to try and lessen the situation.
If the yellowing is on the outside, it may be caused by one of two things:
- A residual hard-coating that has maintained adhesion to the base polycarbonate. These areas may require concentrated sanding to remove the coating.
- The polycarbonate has weathered so severely that it will require removing a significant amount of material to remove the weathered area. It could also be that because polycarbonate is so porous and/or crazed, the cleaner is working its way into the fine cracks/pores of the polycarbonate.
It’s possible that a low-speed buffing (less than 1500 rpms) will bring the clarity and luster back to the lens. This is also a good idea if they’ve become dull. The trick is to use a substance that will not scratch the surface. This should only be attempted by someone who has some experience with polishing polycarbonate. Keep in mind the once the polycarbonate has started to degrade, it is self-propogating. And without the top coat, UV and moisture will readily attack the lens. However, for cars that will see limited exposure, it may provide some extended life.
Polycarbonate, in itself, is relatively sensitive to solvents. As a result, one needs to be careful when exposing a polycarbonate lens to any solvent. Attack may not be readily apparent until the solvent dries and the lens undergoes thermal expansion and contraction under heat and cold exposure.
Moisture condensation on the interior of the lens seems to be common as well. When these assemblies were made, the clear outer lenses were joined to the ABS plastic housing through a heat-bonding process. Over time and usage, and the constant heating and cooling of the materials from daytime and nighttime driving, the two unlike plastics tend to pull away from each other and let water inside the lens, forming a clouding inside the assembly. To clear up the inside of the lens, it must be removed and place inside a warm, dry environment for a minimum of 24 hours (inside the house is fine). Unless the problem of water leakage is resolved, though, this will happen again and again. We’ve not run across the perfect solution for this problem yet, but through some tips from other Cougar owners, we can pass along some solutions to you.
For starters, drilling a small hole (1/8″) in the bottom corner of the clear part of the lens, underneath the assembly, provides a drain hole for any moisture and keeps it from clouding up the lens in the future. Also, you can cover the entire perimeter of the seal with a thick layer of clear silicone. That should last you at least a year of more if properly done.
If All Else Fails
Still can’t solve your problem? Then you’ll want to look into replacement headlight assemblies. There are several places on the Internet that sell them, and there’s always eBay. Or you can take a trip to the local salvage yard for used lights. Here is the information you need to know:
- 1987-88 Mercury Cougar headlamps and 1988-94 Lincoln Continental headlamps interchange.
We’ve not found anything to interchange with 1987-88 Cougar side markers or inner markers; those will have to be for a Cougar only. You’ll have to scour salvage yards for those, or perhaps eBay. Be aware that most yards do not like to separate complete front ends. When in doubt, be sure to ask someone there. They may even have some already pulled and sitting on a back shelf.
Wipers Operate Improperly
If your car is a daily driver (not a show-quality vehicle, in other words), then a few well-placed whacks on the wiper motor with a hammer could get the ol’ wiper motor jump-started. Now if the motor is bad, it’s because one or more of the internal contact brushes on the motor is disintegrated. Banging the casing with a hammer will only temporarily solve the problem. You’ll probably need to either buy a new motor assembly, or find a used one at a salvage yard or whatnot.
But with a little disassembly, you can find out a few things and possibly fix the problem very easily. The “park” contact in the connector housing can get gummed up. To fix it, remove the screws holding the halves together (NOT the wiper motor itself). Drill out the two rivets holding the housing on, pull it away from the base, and remove the pin holding the rocker for the contacts. Under the rocker there are two removable copper contacts and springs; remove them and clean all contacts with fine sandpaper or a Scotch-brite pad. Then, reassemble everything in reverse order (you MUST pop rivet the housing back onto the base, however). Then put the two halves back together and you’re done. Should keep you going for a good long time.
Along with the physical wiper motor there is a wiper regulator module (aka governor) located under the dash, on a steering column support brace, to the left of the column. It controls the electric functions of the wipers including delay and shutting down. Replacement modules can be difficult to find online and can also be rather expensive. Usually a salvage yard piece will function fine but be warned that replacing this module is not fun, since it’s pretty far up under the dash. In fact, it’s easier if you drop the steering column to get to it.
First thing to check: make sure you’ve got enough coolant in the radiator. It’s a common sense thing but it can happen. Also, check for leaks around all the hoses to the block, to the radiator, to the overflow bottle, and to the water pump. If you’re getting a little puddle of green on the driveway or garage floor around the center of the engine, toward the front, that usually indicates a bad water pump. All water pumps are designed with a built-in weep hole on the bottom. When the pump itself goes bad (usually because of a bad bearing), it’s designed to leak antifreeze out the weep hole to let you know this. You can put your finger on the bottom of the water pump to feel this and confirm the problem.
If it’s not any of the above, the next thing to do is get the car warm. What you’re looking to do is see how the thermostat operates and the general flow of the coolant. Take the cap off the radiator when the car is cold, make sure the fluid level is full, then start the car. Leave the cap off for now. It will take about 10-20 minutes, depending upon outside temperature, for the car to get warm and the thermostat to open. If you have a temp gauge, you can keep an eye on it to see where you are. You’re looking for the fluid to drop all of a sudden, and the fluid to jet out of the rows inside the radiator. You may need a flashlight to check this. When this happens, the thermostat just opened and the cooling process has begun. This is normal. If the car is warm but no coolant is moving, or is moving but very slowly, there are several more things to check. You may have a bad thermostat, bad fan clutch, clogged radiator, or (worst of all) bad or clogged heater core, even a blown head gasket. At this point, if you’re not mechanically inclined, you might want to have a repair shop look at your car.
One thing to point out is that the gauge depends on a sending unit (and a warning light gets its signal from a similar switch). It is entirely possible that the sending unit is simply bad from years of usage, and simply needs replaced. For not much money it’s very cheap insurance, and it may possibly solve the problem, although if it doesn’t then you can rule it out.
The thermostat is a likely cause of overheating. Especially on the 5.0L V8 engine, it’s a bear to get out. The 2.3L 4-cylinder and the 3.8L V6 cars are a little easier to get to. You can test your old thermostat by boiling it in water on the stove, and observing the approximate termperature that it opens. It should open a few moments before the water begins to bubble/boil. If it doesn’t open at all, there’s the problem. Again, very cheap to replace. Don’t forget to buy a water neck gasket and some RTV silicone to go with it. And we would highly recommend getting a heavy duty thermostat. It’s only a dollar or two more than a standard thermostat but the construction is much, much better. Stock thermostat rating on the 3.8L V6, 5.0L V8 and 2.3L I-4 is 195 or 197 degrees F.
Fan clutches are known to go, so that’s also a good place to look. This controls the action of the plastic fan blade when the car is moving, and usually kicks on at low speeds or at idle. When the car is cold, the fan clutch should spin around clockwise approximately 1-1/2 times before you feel it resist you. That’s normal. If it keeps on spinning, you’ve got a bad clutch. A fairly inexpensive part.
If you don’t make a habit of getting your coolant system flushed every few years, then your radiator’s internal rows could be all gummed up. A clogged radiator will play heck with you. When observing the thermostat opening in the car, pay attention to the speed at which the water comes out of the rows. It should gush out fairly quick. If you’re getting a trickle or nothing at all, that’s probably the problem. New radiators are not cheap (usually start at $150 US) but the old one can be re-cored. Also, the warranties on most new radiators are only 1 year, so be aware of that. People living in the southern parts of the U.S. (especially the southwest) should purchase 3-row or aluminum radiators to better combat the hotter climate. You can generally use any Fox-chassis radiator in your car, as long as it’s made for the same type of transmission that you have. If you’d like to get a Mustang hi-po aluminum radiator, go right ahead. The price of three-row and aluminum radiators have come down significantly over the past few years so it may be worth the extra money to get yourself one of those.
If you’re getting a slimy film on your windshield from the defroster vents, or you’re getting a lovely wet puddle in the passenger side footwell under the dash, you’ve got a bad heater core. Besides changing an oil pan, this has got to be the absolute worst thing to change on the entire car. See below see full instructions on doing this.
There is the possibility that you’ve got blown head gaskets. For more information on this problem, click here. Worse case scenario, you could have a cracked head or a cracked block.
Hopefully these hints will help you narrow down the cause of your heating and/or cooling problems. While it’s not an exact science to do so, a little trial and error will gain you a ton of experience with handling the problem in your car.
Heater Core Replacement
Special thanks to Lee, Pete, Will, Bob and all at the NATO board for some of the information below.
Probably the number one most-dreaded task that people fear on these cars is the eventual need to replace the heater core. You can almost bet that on one of the coldest days of the year, your core will die and leave you without heat. Well, we’re here to dispel some rumors—this isn’t really that bad of a job at all. If you’ve got an enclosed area in which to work, some basic tools, and a few hours, you can do this yourself very easily. The advantage is that you’ll be saving hundreds of dollars doing this yourself vs. having a shop do it for you. An average heater core change is $300-500+ at a shop. Now if we told you that it can be done yourself for about $100 US and a few hours of your time, wouldn’t you rather do that and save the money? Alrighty then, read on.
The heater core is essentially a small radiator that is tucked inside a plastic box behind your dashboard. Its main job is to allow coolant to flow through once the thermostat has opened. This brings in heat, and then you can run your car’s climate system and fan to warm up the interior. Now this means that you have coolant passing through the firewall and into that box. If you haven’t noticed by now, the firewall is just a barrier between you and what goes on in the engine compartment. Antifreeze is the only liquid that’s allowed (by U.S. federal law) to pass through the firewall and into the passenger cabin, since it’s not flammable. By introducing coolant into the cabin there is potential for a real mess. So be warned now that this is a slimy job. Hey, you want to save money, right?
Symptoms Of Heater Core Failure
- Your radiator is full of fluid, the thermostat works fine, but you still have no heat.
- You find a puddle of antifreeze on the passenger side footwell inside the car.
- You smell antifreeze when you run the heater or defroster.
- You see puffs of smoke coming out of the defroster or vent ducts.
- Your windshield fogs up during or after you run the heater/defroster.
A way to double check this is to get the car warm, and touch both small hoses that go from the engine block to the heater core. If one hose is cold or lukewarm and the other is hot, you’ve probably got yourself a dead core. You can always have your coolant system (and core) flushed and hope that it clears up the problem, but if it doesn’t, it’s core replacement time for sure.
Now that you’ve determined that the heater core itself is bad, you have to get yourself a new one. Now we’re big fans of aftermarket parts as much as the next guy, but no matter what kind of deal you can get at the parts store, it is well worth the money to buy an original Ford/Motorcraft heater core. It’s definitely the best built core on the market, and will far outlast most aftermarket ones. We’ve had people report that their store-bought core lasted a winter or two, and that’s it. Sure, it’s going to be cheaper…but do you really want to do this same procedure again in a few years? Just get the Ford core and be done with it. By the way, this same core was used in lots of Fox cars, including the Mustang, so if you want to shop online at Mustang parts places, feel free. Now you must get the core to match what you have now. So if you have A/C (which almost all of you do), then you have to get the core meant for a car with A/C.
Ford OEM Part Numbers:
Heater Core (cars with A/C) — E9LY-18476-A; also under the Motorcraft number HC-5
Heater Core (cars without A/C) — D9BH-184769-A, D9BZ-18476-B, E25H-18476-AA, E2FZ-18476-A, E4FZ-18476-A, E4FZ-18476-C
Bill has passed along a tidbit of info about the new core: “When you buy the new heater core, have a brace soldered between the inlet and outlet pipes. This will help protect the heater core from engine vibration and ‘I will rip this hose off if it’s the last thing I do’ mechanics!”
Similarly, Darren shared a photo of the bracing on his core, that he had a radiator shop solder in for him.
In addition to the new core, you might want to pick up the hoses that go from the core to the engine block. They’re relatively inexpensive and if you’ve never changed them, now is definitely the time to do that. And when the guy at the parts store asks, “Do you want new clamps with those hoses?”, tell him, “Sure man, knock yourself out.” Now you officially have all your parts. Time to tear into some stuff.
UPDATE: So we happened upon a great video on YouTube that highlights the procedure below, for the most part. Feel free to view it first, as it reinforces much of the information below, and you’ll get a great idea about what you’ll be getting into.
Removal Of The Old Core
Yeah, this is the part where most people freak out. No matter what you’ve heard, you DO NOT have to remove the entire dash. The dash only needs to come out far enough to get access to the heater core box. But that comes later; you have to disconnect a few things first.
If you still have the original-style R-12 refrigerant in your a/c system you MUST get it recovered at an official facility that can do so. They’ll can it for you to use later if you wish, or you can convert over to R-134a. DO NOT let refrigerant bleed into the atmosphere! Now if you have R-134a already in there, bleed the system dry. Or if your a/c doesn’t work (which I’m betting is the case for most of you out there), do nothing. The trick is to do the heater core swap within a day or two so you don’t get a lot of atmosphere (and therefore moisture) in the a/c lines. That will prematurely rot out the system with rust.
You first have to remove the a/c accumulator on the firewall from inside the engine compartment. Disconnect the a/c lines going into the firewall (to the evaporator core), then remove the bolts from the strap holding the canister and remove the canister. After it’s off, remove the second set of large nuts underneath that strap. These are the nuts that physically hold the core box to the inside of the firewall. You’ll also have to remove the rubber coolant lines going from the core to the block (you’ll likely need to drain your cooling system to do that). If the core hoses are old and are giving you fits coming off the core, cut them off lengthwise with a utility knife and peel ’em off. Once you’ve done this much, your work outside the car is pretty much done for the time being.
You should NOT have to remove the following:
- Instrument cluster
- Glove box (although it helps a little)
- Heater ducts
- Ash tray on non-console cars
You will have to remove this stuff though:
- Under-dash insulation (driver and passenger side)
- Kick panels (driver and passenger side)
- Console (if equipped)
- Floor shifter and bezel (if equipped)
- Console bracket
- System Sentry module, if equipped
One more thing before getting too deeply into the job here: the following photos and descriptions are intended for the majority of 1983-88 Cougars and Thunderbirds. They may or may not be exactly what’s in your car. For example, if you have automatic temperature control (ATC) then you may have a different setup behind the dash than a non-ATC car. Therefore these pictures and descriptions obviously would be different than what may be in your car. If you feel that you have something to contribute that would help others, feel free to contact us.
Because of the nature of this older dashboard setup, you will have to remove more fasteners than on a 1985-88 dash. But don’t worry, we’ve got them all outlined here for you. Very special thanks to Darren for providing the photos and info below.
To remove the dashpad there are a total of 10 screws that need to be removed. There are 4 total, 2 down in each windshield heater vent, on the top as seen here.
Next, remove the 2 special screws, one on each side of the dashpad.
There are 4 screws that attach the dash pad to the dash trim panels, two on the driver side and two on the passenger side. This is the one on the driver side to the far left to give you and idea of what you are looking for. Remove all 4, and then you can lift the dashpad off the top of the dashboard.
There are 5 Philips screws holding the top of the dashboard to the firewall: 2 by the left speaker, 1 in the center, and 2 by the right speaker. Remove those.
Remove the kick panels and unbolt the two screws that hold the lower dash (passenger side shown, driver side typical).
Additionally, there are two more support braces: one is in through the glove box at the back of the radio (see the 1985-88 directions below), and another is below the dash on the driver’s side, as shown here. After these braces are unfastened, the dash should be free enough to come out from the firewall.
It may help to tie a bungie strap to the dash and hook it around the headrest to keep it pulled away from the cowl.
There are 3 machine screws and 4 nuts that hold the air box in the car. One machine screw is self tapping and is at the bottom of the air box in the passenger foot well as seen here.
Then there are 2 machine screws that attach the air box to the firewall at the base of the windshield which are identical to the 1985-88 setup.
The A/C accumulator/dryer is in the engine bay and it will need to be removed from the bracket that affixes it to the firewall. This bracket is on two studs that are part of the air box. Once you remove the A/C accumulator/dryer from the bracket there are two nuts that affix the bracket to the studs. Remove the nuts and remove the bracket.
Now you will see two washered nuts that will need to be removed so that the air box can be removed. The A/C accumulator/dryer is already removed in this photo. Also note that the heater core hoses have been removed—if you haven’t done so yet, be sure to remove them before going any further.
You are now ready to remove the 5 machine screws that hold the heater core cover onto the air box. When you remove the cover it may take some gentile prying but be patient and pry at multiple locations. Once you get it off, you’ll need to clean all of the old seal off the air box and the cover. Silicone works well; optionally, a new butyl rope seal will do a great job and is actually what was used at the factory. It’s installed on the air box and the cover in these pictures.
Here is the new core installed in the air box and the inlet and outlet are through the rubber/foam seal for the firewall.
And with the cover installed.
You’re technically now finished with the heater core replacement. Reinstallation is the reverse of the above. Scroll down to the end of this article for final notes.
Now what if we told you that there are only 7 bolts and nuts holding your dash to the cowl? Trick is knowing where they are.
(Thanks to Frank for sharing the photos!)
A diagram showing some of the bolt locations.
Remove the speaker grilles from the dash, along with the cover in the center of the dash. You’ll see one 7mm bolt under each cover; remove all of them. Left speaker grille bolt.
Center cover bolt.
Right speaker grille bolt. That’s 3 out of 7.
Remove the kick panels (below the dash, to each side) and remove the bolt on each side holding the dash to the car. Driver’s side.
Passenger’s side. That’s now 5 out of 7—not bad, eh?
The last two* will be 10mm nuts; they’re sometimes painted blue so they’re easier to spot. Drop or remove the glove box and inside toward the back of the radio, there is a big metal bar that bolts to the outside of the radio metal support. Remove the nut from it and shove the bar off the stud.
*NOTE: Some car owners (especially of Turbo Coupes) have reported that they do not have this brace. If you don’t see it right away, you probably don’t have it—skip this step.
For #7 you’ll have to remove all 4 bolts holding up the steering column. They should be 5/8″, deep well. The column will simply drop to the seat or the floor; it should be okay to let it hang there if you’re not going to be long, but support it if you can.
If your car has a column shifter, Dan writes, “Before dropping the steering column, be sure to remove the PRNDL cable from the steering column before removing the nuts holding the steering column to the bottom of the dash (the white cable that goes from the instrument cluster to the column.) It is visible once the lower column shroud is removed. I noticed on my car, that if it is not removed, the column’s weight will hang on it and it will most likely break if not disconnected.”.
Under the instrument cluster and back under the dash, you’ll see nut #7 which should also be painted blue. The stud is aimed towards the floor and the nut is parallel to the floor. Remove it completely (don’t just loosen it), and you’ll now be able to wiggle the whole dash free. You won’t be able to fully remove the dash from the car, but you won’t need to when changing the core. You just need enough space to get to the heater box. What you want to do is get the passenger side out as far as possible. Be very careful when doing this—these are old dashes and they can crack easily. Have someone hold it, or support it, before going any further.
If you find that you cannot get the dash out very far, double check to make sure all of the bolts are out. If you’re sure they are, you may need to disconnect some harnesses in the passenger side kick panel area, by the computer.
The core box is on the passenger side; it’s black and plastic. There are two straps on the top holding it to the cowl, and in each strap is a bolt. Remove those two bolts. Way underneath the box is another bolt, down by the transmission tunnel along the carpeting. It’s tricky to see but you’ll find it.
Be very careful of the hot-cold selector cable! If you don’t disconnect it before removing the heater box you can risk pinching or breaking it.
Once those 3 bolts are out the box can be wiggled from the dash and dropped down. On the top of the box is 4 bolts that hold the cover on; remove all 4 and the lid, and underneath—voilá!—is the core.
NOTE: Some owners have reported that it’s a little more difficult to get to the top of their box. This may be due to having the ATC system. You may end up reaching through the glove box hole, or from outside the car, to get to the bolts on top. Just be patient and you’ll get them.
NOTE 2: Another owner has reported that on ATC cars, you MUST remove the entire blower assembly from the car in order to reach the screws for the lid. He says: “The location of the bolts that encase the heater core itself are not conducive to being removed inside the car. They don’t face the firewall. There are five 7mm bolts that face the top of the dashboard, and you will never have room/leverage to get them out inside the car, so the assembly MUST COME OUT. Once out, just remove the bolts, and put the new core in.”
Now you may notice that there’s another little friend hanging out in the heater box with the core. That’s his buddy, the A/C evaporator core. Most people can simply ignore it. Now if you have removed the A/C system or are going to, then this is the perfect time to remove it, but be careful: you have to cut up the top of the box to get it out, and that ruins the top. It may be possible to find a factory non-A/C lid but we wouldn’t put too much faith in finding one easily. Silicone is about the best way to repair that lid afterwards but that’s okay, because you’re going to need silicone anyway.
There’s nothing tricky here—simply swap the old core for the new one. Now there is a weird rubbery/wire seal inside the lid of the core box that probably will fall apart when you removed the lid. It’s technically a hermetic seal but it’s shot after you’ve broken that seal. Take all of the old seal out and hit the lid with generous amounts of silicone before you put it back on. Also, if your core has been leaking into the passenger footwell, you’ve probably got yourself a miniature green ocean in the bottom of the box. Clean all that stuff out and get it nice and dry.
Once you’re done, you’re ready for reassembly, which is—no surprise—the reverse of all the above. Don’t forget to put the coolant lines on under the hood, and bolt up the rest of the A/C stuff. Fill the cooling system back up, reconnect the battery, and start the car. Immediately turn on the heater, full blast. Let the car warm up until the thermostat opens. You should then feel a ton of heat inside the vehicle…if so, you’ve done your job properly and can now leave that extra jacket in the house. Open up a cold one to celebrate, ’cause you deserve it!
While You’re In There…
…it’s been suggested by Curt, a professional mechanic, that you may want to consider replacing your blower motor at this time, while the dash is apart. If your car has a lot of mileage, or you hear a grinding/squeaking noise every time you turn on the fan, chances are your blower motor is going bad on you. A new blower motor should run around $50 U.S.
Darren also suggested that now would be a great time to install the heater core flow restrictor in the inlet hose to keep the core from popping at higher RPMs. It can be found under the Ford Racing part number XR3Z-18599-AA.
All this probably sounds like a lot of work but it’s really not. Ford tells their dealerships that they have 8 hours per car to do the change. You’ll probably do it in 3-4 hours tops. The hard part is the a/c stuff; once you’re past that it’s a piece of cake.
Fords generally need just about 100 percent voltage for ignition. Any power drop or bad connections and it won’t start, period. After ensuring the battery voltage is at least 12.2v, the first thing to check is your battery connection. If there is any hint of corrosion around the terminals that’s usually the problem. Sometimes you can’t even see any gunk but it’ll still cause the same problem. A terminal cleaner should be mandatory in any Ford owner’s toolbox; that’ll keep them clean and prevent this problem from occurring again. Also it’s highly recommended that you keep the terminals protected from any future corrosion. Those red and green felt washers they sell everywhere really do a great job. Or you can use terminal cleaner or even grease. If your battery is not maintenance-free, make sure it has enough water (always use distilled or reverse-osmosis water when filling, not regular tap water).
The next step in the line would be the starter solenoid, located by the strut tower nearest the battery. If you happen to overtighten one of the nuts on the terminals, chances are you can break the contact internally, and you’ll get intermittent or no starting. This also happens over time naturally. Fortunately, solenoids are very inexpensive and it should be very readily available for your car/engine bay. It never hurts to have a spare laying around anyway.
If you happen to have a 1983-84 vehicle you have a Duraspark II ignition system. Bruce has provided a link to help troubleshoot this system, along with some diagrams and vital information.
Lastly, if a solenoid swap-out doesn’t solve the issue then you could have a power drain, bad battery, bad voltage regulator, bad alternator, bad ignition switch, bad TFI module, bad starter motor, etc. But at least these tips will not you cost much to eliminate some possible causes.
TFI Ignition Module Failure
What is a TFI module?
TFI stands for Thick Film Ignition. The module itself consists of some solid state electronic components suspended in a thick, clear electrolytic film, hence the name TFI.
What is the TFI module’s function?
The TFI module (also known as a spark module) is necessary to control the spark output of the ignition system via the EEC (electronic engine control) computer. A signal from the TFI module is sent to the EEC and the computer then controls the spark to the spark plugs. It is a very necessary and vital component of the entire EEC-IV engine management system.
Where is the TFI module located?
Depending upon the engine configuration, the module is usually found on the distributor itself, on the front of the motor:
This module is located on the side of the distributor. Shown here is a 1986-88 Cougar 5.0L V8 engine.
On some cars, the module has been relocated to the front of the radiator core support and is surrounded by an aluminum heat sink. The module below is on a 1988 Cougar with the 3.8L V6 engine.
What is the problem with the modules?
Due to excessive heat from the engine, the module has been known to stop working or intermittently work, resulting in stalling or cutting out of power to the vehicle’s ignition system. This situation has been known to cause stalling and accidents, although it is not clear whether any accidents resulted in serious injury or death.
What Ford vehicles are affected by this problem?
Any Ford vehicle with the EEC-IV engine system, from late-1983 through the mid-1990’s, has a TFI spark module, including Cougars and Thunderbirds. Pre-1983 vehicles do not have this module. Vehicles with DIS (distributorless ignition system) also do not have a spark module.
I’m concerned. What should I do with my vehicle?
If you are concerned about your car’s TFI module, the first thing you should do is have a qualified mechanic inspect it physically. This requires removal with a special tool. There are two Torx screws sunk into the module that hold it to the distributor (or heat sink). Once they are removed, the module unsnaps from its base, and then the wiring harness can be unhooked. On the top (grey) side is an inspection cover, under which is the thick film. There should be no seepage of film, nor should the film be dried up. Also, the plastic around the mounting screws should not be cracked at all. Any cracks will allow the module to pull away from its base, cutting out power and possibly hampering ignition. The module’s halves should be flush and fitted tightly against one another. There should be no brownish discoloration at the harness end. Finally, there should be a generous spattering of dielectric grease (clear or white in color) on the metal backside of the module. This is to help promote electrical conductivity with the base. Upon replacement, the old grease should be wiped off and a new fresh coat applied, approximately 1/32 of an inch thick. Be sure to inspect all wiring around the module to make sure there are no breaks or pinholes that may short out the system. In an electrical test with an ohmmeter, the TFI module should be below 800 ohms or over 975 ohms. If the module falls between 800 and 975 ohms, it must be replaced.
Can I replace the part myself?
If you feel that you can do this yourself, the tool to remove the module is only a few dollars at any good auto parts store. Be sure to disconnect the vehicle’s battery before attempting to remove this or any other electrical component of the car. Use a name brand TFI module to be sure you are getting a quality part. We highly recommend using a Motorcraft TFI if possible. The cost of the part itself should be anywhere from US $15-$50 for your vehicle. Keep in mind that there is no guarantee that the new part will be assembled better, or less prone to the problem, than the old module. However, a new module will at the very least provide more accurate information to the computer and is very inexpensive insurance.
Owners of vehicles with the TFI modules mounted on the radiator core probably will have fewer problems with excessive heat affecting the module. This is because of a large heat sink (dissipator) around the module itself, and the cooling effect of incoming air as you drive. However, it is still recommended that you have it inspected for other problems mentioned above.
Should you wish to relocate your distributor-mounted TFI to the front radiator core (or really, any other free spot that gets good airflow), it is possible to purchase a TFI relocation kit. It will come with a wiring harness extender, the heat sink, and all appropriate hardware and instructions. Some companies offering TFI relocation kits include MuCully Racing Motors and Fat Foxx. This is an excellent way to solve an issue that the factory never got right.
Inertia Switch/Fuel Pump/Relay Problems
When you turn the ignition key forward (‘ON’) but do not fully start the car, a signal is sent from the ignition switch to fuel pump relay in the trunk, then to the inertia switch, then to the fuel pump in the tank (or on the framerail, depending on your model year). The fuel pump will audibly hum for a second or two in order to prime the fuel system and build up pressure. If you do not hear the pump humming, you must look to either the relay or the inertia switch first before you drop the tank for a pump change.
Fortunately you can see that with only a few breaks in the fuel system’s electrical components, it’s fairly easy to troubleshoot if there is a problem with starting the car. Here are some basic guidelines for finding a problem in the electrical part of the fuel system.
If your car has been in a rear-end collision, or if there is some other type of sudden hard blow to the rear part of your car, chances are it won’t start. This is because the inertia switch, also known as a fuel cutoff switch, has been tripped. This switch exists on modern fuel-injected cars as a safety measure when accidents occur, cutting the fuel pump off thereby eliminating the fuel flow to the engine, where a fire or explosion could occur. The system is pretty basic but ingenious, letting a simple spring lock and a few wires do all the work. A white colored button on the top of the switch is always in the down (locked) position to allow power to the fuel pump. When the area around the switch is suddenly jolted, the switch pops up from inertia. All you need to do is simply press the button down until it locks, then try starting your car.
In 1983-86 Cougars and Thunderbirds, the inertia switch is tucked away in the trunk on the passenger side, behind the metal rail next to the trunklid hinge. For cars with a trunk liner, there is an access hole in the liner on that side to reach the white spring-loaded button on the inertia switch. Cars without liners still have an access hole in the metal.
The white arrow indicates the access hole through which the reset button is located. In case the switch ever needs to be replaced, the orange arrow indicates the screw that needs removed.
A tight shot of the inertia switch from the back side of the metal panel. On the top you can see the white reset button.
In 1987-88 Cougars and Thunderbirds, the inertia switch is on the taillight panel inside the trunk, on the driver’s side. There is a hole in the trunk’s taillight cover panel through which you can access the white spring-loaded button on the inertia switch. There is no need to remove the cover.
With age and especially in climates with extreme temperature changes, the inertia switch can fail all by itself. The spring lock mechanism that holds the button down can rust or become stretched, and the button will pop up at will. This can happen particularly on a very cold night. Understanding this problem before it happens can be a blessing! If you’re stuck somewhere and this is indeed the case, you can temporarily tape or zip-tie the button down securely to get you home. A new switch usually lists for around $80 US and can be easily changed yourself. This may still be a Ford dealer-only item; nevertheless, feel free to shop around.
Fuel Pump Relay
If your car’s fuel pump will not turn on and you know that the inertia switch is good, or if the fuel pump keeps running after the ignition is turned off, then you have a bad fuel pump relay. It’s the only part on the whole car (aside from the ignition switch) that can cause either problem. All you should need to do is change the relay to fix the problem.
The fuel pump relay is found in the trunk behind the back seat, on the passenger side. The relay itself is about 1″x1″x2″ and is a green color, attached to a black housing. The location of the relay depends on the model year:
In 1983-86 Cougars and Thunderbirds, you’ll find the relay attached to the seat’s metal support brace, or sometimes hanging behind the rear seat cushion.
In 1987-88 Cougars and Thunderbirds, the fuel pump relay is attached to the trunk support panel. This is directly behind the trunklid hinge.
Replacing the fuel pump relay is very simple: simply pull hard until it detaches from the black housing, and replace with the new relay. You can find fuel pump relays at the Ford dealer or at parts stores nationwide.
If for some reason changing the fuel pump relay does not solve your problem, then you will have to replace the ignition switch.
If you’ve ruled out the interia switch, fuel pump relay, and ignition switch as the causes of your starting problem, then you are probably looking at a fuel pump replacement. In general, fuel pumps will either slowly die, or just quit without warning. If you’re lucky you’ll get some warning signs first, like very long starting times, erratic idle, cutting out under heavy throttle, and hesitation. Or you will hear the hum of the pump get noticeably louder, or have a high-pitched whine. After awhile your car simply won’t start because the pump refuses to turn on.
You may be tempted to replace your fuel pump with one from the local parts store. Now we won’t berate anyone’s business, but many readers have reported that generally you will not have good luck with most of these pumps. It’s common to have to replace these parts-store pumps every few years, if not sooner. You surely don’t want to drop the tank every few years to change the pump, even if it is under warranty! The only tried-and-true factory-style fuel pumps will come from the Ford dealer. Surprisingly they are reasonably priced so don’t let the cost factor keep you from making the trip. As with heater cores, the Ford pieces are second to none in quality and longevity. It’s not worth saving a few extra bucks on an inferior pump, especially when it’s such a necessary part of the car, and something you depend upon daily.
We have had good luck with high-performance aftermarket pumps. If you have a 1986-88 5.0 car, or any other car with just an in-tank, high pressure pump, you can install one of these. Places like Summit Racing and Jeg’s are good places to find them. You won’t find these listed for a Cougar or Thunderbird, but you can use a Fox Mustang pump. Just so you know, you only need the pump itself, not the pickup assembly as are sometimes sold with Mustang pumps. The Mustang pickup assembly will not work properly in your tank, so don’t waste your money on something you can’t use. As for the ratings, the stock high pressure pumps (5.0L V8, some 3.8L V6) put out around 88 liters per hour (lph). Depending upon your engine’s performance parts, you can upgrade to a pump with a higher volume output. The bare minimum considered for a performance pump is 155lph; 190lph is more desirable. BBK is one of the few brands where you can buy just the pump without a pickup assembly. Also, do not be confused by pumps that are listed in gph, or gallons per hour. These flow much more fuel than you’ll probably ever need. Stick with a pump that’s rated in lph.
When you install a new pump in the tank, whether a stock-type or a high-performance aftermarket pump, you will reuse your old pickup assembly. The new pump may have to be zip-tied to the assembly, as some aftermarket pumps are a little smaller. Also, some rewiring may be necessary to get an aftermarket pump to work. Don’t worry: there are only two wires on the pump, black (ground) and red (power). Make sure your electrical connections are super-safe! Also, you can reuse the sock if it looks pretty clean. Sometimes aftermarket socks don’t fit our pickup tube very well. When you’ve got the new pump in, the fuel lines and wiring connected, and the tank back into position, you have to prime the system before starting the car. Turn the key forward (‘on’) but do not start the car. Listen for the tank to make a noise; it can be a slight buzz or a muffled gurgle. Turn the key back off, wait a second or two, then turn it forward again. Do this 5 or 6 times to fully pressurize the fuel system, then start the car all the way. It should fire up immediately and the pump should run normally. Any sputtering may be electrical in nature so be sure to double check your wiring before reassembly.
Lastly, whenever you drop the tank and/or change the pump, don’t forget that you will need to change the fuel filter. This is because you will stir up any sediment that’s been sitting on the bottom of the tank, no matter how gentle you are. You don’t have to change the filter immediately after a pump install, but you should within 10 miles or so, which is usually enough of a distance to get you to a gas station to fill up the tank, or take the car for a spin to make sure everything’s working properly. Basically you want the pump to kick up the big, nasty sediment into the old filter for at least a little while before putting a fresh filter in. Changing a filter immediately after a pump replacement can be premature in this respect.
Clunk When Letting Off Throttle
We’ve also been told by mechanics that it could be something in the tailshaft of the transmission. While this would be an impractical (and probably expensive) problem to fix by itself, it’s something worth mentioning if you ever have to get the transmission rebuilt or replaced.
Hard Gas Pedal
To confirm that your throttle cable is stretched, make sure the car is in Park and that it’s off. Next, remove the insulation panel above the gas pedal. Then, get yourself a flashlight; you’ll need it to see the pedal up high under the dash. Unfortunately, you have to squeeze in under the dash just like you’re changing a fuse. Shine the light up on the accelerator pedal shaft. There is a black grommet on the top of the shaft, with the throttle cable inside that grommet. At rest, the metal cable end should be pulled tight against the grommet. If you see any additional cable sticking out from the grommet, or if there’s a lot of play if you wiggle the gas pedal, there’s your problem (see arrow in photo).
To thoroughly solve the issue you should strong consider buying new throttle cable. However, we’ve received a few tips about putting spacers or Zip-ties on the cable (either at the throttle body or at the gas pedal) to make up the slack. While that can work (and to be honest, we’ve done that before too) it is pretty much a bandage to do so. You’re still going to stretch the cable further, and that can lead to it breaking. Replacement is the safest long-term solution.
A new throttle cable is usually around US $40-60 if you can find one. As these cars age, some things are getting more difficult to find and this cable tends to be one of them. Now if you own a 1986-88 5.0L V8 car, you can use a Mustang throttle cable which is available on many Fox Mustang parts sites, or even eBay. For other engines and model years, you will have to search pretty hard. We are unsure if they are available via the Ford dealer or local parts stores but you can try.
Kickdown Cable Inspection
If your throttle valve (TV)/kickdown cable is stretched, that also means your transmission linkage may be stretched too. Be sure that this is also inspected at the same time—there should be no slack in this system either. Just FYI, a stretched TV cable will cause long term damage to your transmission, requiring the dreaded rebuild. If your car has linkage instead, you might need to either adjust it, get new bushings for it, or replace it altogether. The linkage is more money because there are more parts involved in the system. You will need to check your local parts store for your particular transmission and model year, as linkage differs greatly.
If you cannot find the cable(s) or linkage at your parts store, then you may have to dig deep at the dealership or on eBay (be aware that many other Ford models used the same cables). And if THEY don’t have one, your only choice will be to fabricate your own using a universal kit. Lokar makes universal and some transmission-specific kits that may be useful.
3.8L V6 - Surging
Since your ignition system uses several components in sync, the cause could be one or more things. On the 3.8L V6, there’s a TFI (thick film ignition) module on the distributor that likes to blow out suddenly; this can also cause the car not to start. It could also be a bad TPS (throttle position sensor), which causes all sorts of strange things to happen to your car. A bad or sticking IAC (idle air controller) motor is also very common on these cars; you might consider checking and/or replacing it.
Other culprits could be bad spark plugs, spark plug wires, ignition coil, EGR valve, MAP sensor, or even a bad EEC computer. The 1984-85 V6 cars are especially susceptible to faulty EEC-IV computers from the factory. This is a trial-and-error kind of problem, unless you have a computer code reader, but fortunately most of the components are not very expensive and can be found rather easily.
If you’ve determined that the cause is not electrical, then you just may have a bad timing chain. The 3.8 timing chain will stretch over time (as do all timing chains) but for some reason, this engine seems particularly susceptible. The stretched chain will allow the valve opening and closing, and your piston and firing order, to become out of sync with each other. Eventually this will severely affect performance and can cause the camshaft to snap. As a general rule, a new timing gear set and chain should be installed every 75,000 miles on a 3.8L V6. And this problem usually will not show up on an EEC tester. If you are experiencing this problem, we’d recommend getting a second opinion from a qualified mechanic. As common as this problem is though, it just could be the ticket to new life in your engine.
3.8L V6 - Head Gasket Replacement
A blown head gasket will cause temperature fluctuations at first. Then you’ll suddenly get huge plumes of white smoke from your exhaust pipe. This means PULL OVER IMMEDIATELY AND SHUT THE CAR OFF. If you’re lucky, you didn’t crack or warp the heads or crack the block. The sooner you shut the car off, the better you should be. From this point you can have the car towed and a compression test done, but sometimes you’ll absolutely have to have the heads pulled and examined. Usually you’ll find the gasket blew out at the #1 or #3 cylinder. If the heads and block are not cracked or warped, then the good news is, you just need to get new gaskets. There is a special 3.8 V6 replacement gasket kit available from Ford that includes new redesigned head gaskets, or you can use Fel-Pro gaskets. Also, it may be a good idea to have your heads shaved down a few thousandths just to be safe. There may be a slight warping of the heads and you definitely don’t want to reinstall them in that shape. Machining should be around $50-100 US.
If your heads are cracked or warped beyond repair you’ll need some new ones. Now on one hand, they’re plentiful and cheap at salvage yards and you can usually inspect them before you buy. But be forewarned that you could end up in the same situation again since this is such a common problem across the board.
We’ve had excellent luck using new heads from Clearwater Cylinder Head Inc. in Clearwater, FL. The heads are all-new, not remanufactured, from new castings. It is unknown whether this new casting has revised anything from the original design, but we can absolutely attest for their quality as we’re running them in one of our cars. CCH stocks heads for all versions of the Ford 3.8L V6. Cost is very reasonable at around $150 US/each, including shipping and the return call tag for the old heads for core.
Clearwater Cylinder Head Inc.
5100 Ulmerton Rd., Suite 2
Clearwater, FL 33760
Toll Free: 800-572-1963
And just so you know, the FWD Continental/Taurus/Sable versions of the 3.8L heads are different from those used on rear-drive vehicles, so be sure to order them for a RWD car.
Now if the new heads work out, excellent…coupled with a pair of good-quality head gaskets, you’ll be in great shape for a long time to come. But if you find that that the engine block is cracked, you’re in for a whole new set of problems.
You can get remanufactured motors at Pep Boys or other major automotive parts stores for a decent deal. Be sure to check the warranty details before you order. The boneyard is a plentiful source of 3.8L motors…but again, you could end up with the same problem. The yard itself should be able to tell you the condition of the motor before it was yanked. You should try to get a block from the same model year as your car. Generally, for all RWD cars, 1982-83 blocks are the same; 1984-87 are the same; 1988 is unique (internal balance shaft); 1989-93 are the same (naturally aspirated); 1994-2003 are the same (naturally aspirated). The Super Coupe block was used from 1994-2003 on all 3.8L V6 RWD engines, but because of the different block design it will not retrofit using older heads, intakes, etc. For more information about the 3.8L V6, and the parts breakdown by model year, see this website.
5.0L V8 - Knocking/Pinging
The only permanent solution to get rid of the noise is to change the pistons, and as you can imagine, that’s not fun, practical or cheap. You can try to use some motor treatments or thicker weight oil and see if that helps; some people report that it does. Or try running premium unleaded gas (93+ octane). Not all motors make the noise, so yours just might be one of the lucky ones. Otherwise you may just have to live with it. We’ve been assured by many Ford professional mechanics that this will not cause any damage to the cylinder walls or the cylinders themselves. Incidentally, when this problem was first detected in the late 1980’s, Ford issued a “secret” recall on the engines, which meant that if a customer complained enough, Ford authorized their dealers to replace the entire engine at Ford’s cost. Unfortunately that lasted only a few years, and you cannot get a new engine anymore, so the solution is up to you now.
5.0L V8 - Motor Uses Oil
The problem seems to be the slightly undersized piston rings from the factory. Especially with the 1986-88 5.0L engines, the flat-top aluminum pistons were purposely made a tad smaller than a comparable forged piston, so that when the engine reached normal operating temperature the pistons would expand correctly. Since cast iron (block) and aluminum (pistons) expand at different rates, this makes sense…on paper. In reality, until normal operating temperature is reached, oil has the potential to get sucked into the combustion chamber if the piston rings are worn enough. If you kick the car into passing gear and see a small cloud of smoke behind you in the mirror, that’s the bit of oil you just burned. While not a major problem it’s semi-annoying, and it does cost you money to buy extra oil between changes. Again, the only way to solve the problem now is to replace the piston rings. But if you’ve got knocking as well, you can kill two birds with one rock and have them both changed, eliminating your knocking and oil-eating problems permanently. Make sure you check for external oil leaks around the oil pan, filter, and valve covers first.
Transmission Shifts Erratically
The TV (throttle valve), a.k.a. kickdown, cable attaches to your throttle body. (Some cars have rod linkage instead of a cable; this still applies to you). Its purpose is to downshift the transmission during deceleration, and control upshifts on acceleration. There is a plastic bushing that mounts the cable to the throttle body plate. When it breaks, your cable (or linkage) becomes detached, and you get funky shifting. Now this is not a good situation for you, because riding around without a kickdown cable can cause immediate internal damage to the transmission. The new bushing kit is roughly US $2 at nearly any good parts store and should be in stock since this is a common occurrence. Or you can order online at places like LMR (Ford dealers have it under p/n F3SZ-7H303-B). You may need to drill out the hole in your throttle body lever to ~3/8″ for the new cable to work, depending on your model year. In a pinch, you can tie up the cable with a plastic Zip-tie or wire with satisfactory results. Keep in mind that this is a potentially serious problem and should be taken care of ASAP. This problem is most associated with the AOD transmission.
So what if it’s not this little part? Well, if you have a C5 (or transplanted C4) there is a modulator valve on the transmission casing that can go bad. Also, there will be a vacuum line attached to it, as this controls the line pressure. Changing the modulator usually helps, although you cannot discount a cracked vacuum line. In any case, that fix would be rather inexpensive as well.
If you have the AOD, however, things don’t look too good for you. In general, Ford transmissions simply go at their own discretion. Doesn’t matter that the day before it shifted perfectly; it can simply go out on you at any given moment. This can happen anytime but most prominently after 100,000 miles. So should one live in fear of the transmission going? Well, if the car’s shifting fine and you actually remember to change the transmission filter and fluid on a regular basis, then you’ll be okay. But just try to keep that in the back of your mind…and in your bank account. As always, it’s recommended to see a professional and get their opinion too.
Automatic Transmission Help
Taking Care of Your Transmission (C3, C5, AOD)
It is recommended in your owner’s manual that all automatic transmissions should have the filter and fluid changed at least every 30,000 miles if not sooner. This is a pretty good regimen to follow. Usually a trans fluid/filter change is fairly inexpensive at a shop, and less if you do it yourself. However, there are two schools of thought here: 1) routine maintenance is good, or 2) if it ain’t broke, don’t fix it.
In talking with several professionals, including our own personal mechanics, the thought of keeping the fluid as-is for extended periods of time is not an uncommon sentiment. The theory is that the fluid will contain deposits that can build up in the passages throughout the valve body. These deposits are akin to carbon buildup in the upper intake plenum. The transmission “gets used” to having these buildups, which are normal. If you change the old fluid, the new fluid will flush away those deposits, and the likelihood of changing the transmission shifting and wear patterns is high.
Does this mean you shouldn’t change the fluid and filter? Well, not if you can help it. So long as the transmission is shifting well and you suspect no ill behavior, you’ll probably be alright. But there will come a point where you will need to change the filter at the very least. If you suddenly can’t put the car in gear, if the shifting becomes erratic, if you have hesitation, or sometimes if the car won’t even start, those should be clues that you may need a transmission filter change. And obviously, when you take the transmission pan off, you’re going to lose all the old fluid. So when you put the new fluid in, you may want to put some transmission fluid additive in with it. It’s supposed to keep all those deposits in place, so that your transmission should shift about the same as with the old fluid. We recommend the additive simply because it’s inexpensive insurance. Any good parts store will have trans fluid additive.
In addition, all factory automatic transmissions used in our cars can benefit by using synthetic transmission fluid. Because of the man-made components in the fluid, the passageways inside the valve body will become slipperier, thereby allowing better fluid passage and reducing friction (and heat). Remember that heat is the number one killer of transmissions; anything you can do to keep the heat out of the transmission will keep the inevitable rebuild away.
Adding an external transmission cooler will add greatly to the life of your gearbox. If you tow, are in lots of stop-and-go traffic, do lots of highway driving, or idle quite a bit, then you likely need to get an additional cooler. Now from the factory, all automatics have a cooler that’s built into the side of the radiator. It’s a noble idea from the factory…in reality, though, it’s just adequate enough to keep the transmission cool. The new external cooler will bypass the cooler in the radiator, and will actually attach to the front of the a/c condenser. You will need to either adapt your stock transmission lines, or cut them and attach new ends, in order to get them hooked up to the new cooler. Adapting is much simpler and only requires a few new brass fittings. The advantage is that you can always go back to the radiator tank cooler if you need to. You can buy transmission coolers from almost any parts store. You won’t need anything really heavy duty; buy one for the minimum GVWR or the next one above that.
The ubiquitous shift kit will firm up your shifts, prolong the life of the transmission, and give you slightly better gas mileage. Shift kits work better in conjunction with a higher stall torque converter but that’s not required. Most of these older-style mechanical transmissions (meaning those without the aid of electronics) can benefit from a shift kit. And you can tailor the kit to make the transmission shift to match your driving style—crisp, firm, or head-snapping. The trouble is, how do you know which kit to buy? In this area especially, you get what you pay for. Now we won’t be slamming any companies’ products here, but typically the lower-priced kits are going to give you more problems than the more expensive kits. The Baumann Engineering kit and the Trans-Go kit are both excellent and are highly recommended. If you decide to install the kit yourself, it’s about a 4-hour process and can be tricky if you’re not careful. When in doubt, have a professional do it for you.
By the way, the 4-cylinder automatic transmissions (C3 or A4LD), used in rear-drive 4-cylinder Ford applications (including the Mustang and Ranger), are usually weaker pieces to begin with since they weren’t designed to handle the torque of a V8. Any shift kits or souping up in these would probably hasten transmission failure.
The stock torque converter stalls at approximately 1500-1800 rpms. This is okay, but for engines with moderate to heavy modifications, a higher stall torque convertor is a must. Usual ranges vary from 2000 rpms to 3500+ but you’ll need to talk to a transmission specialist to find out what stall speed is best for your car, as you need to select a converter to match the camshaft you’re using. Remember that when you raise the level of camshaft performance with the motor, you will almost always need to raise the converter to match.
Precautions (AOD only)
Since all V8 Cougars and all 1987-88 models had the AOD (along with some earlier optioned 3.8L V6 cars), it’s safe to say it was one of the most commonly used transmissions in the 1983-88 body style. But thanks to that AOD band it’s also the most troublesome. AOD’s have problems that are all their own and you will need to know about your transmission more than owners with a C3 or C5.
The main thing to watch is the TV/kickdown cable grommet on the throttle body. This mainly concerns 1986-88 V8 models but is also true of 1988 V6 cars. From the factory the end of the TV cable is pushed into a plastic grommet on the underside of the throttle body lever. At the time of design it was probably a money-saving solution. But it’s proven to be a faulty design, one that can kill an AOD in a heartbeat. What happens is that over time, and with constant heating and cooling, the plastic grommet can crack and allow the TV cable to become disconnected from the throttle body. Driving without the TV cable attached will almost immediately kill an AOD. Fortunately there is a very inexpensive cure for the problem—Ford has issued a kit (p/n F3SZ-7H303-B) that completely replaces the grommet with a brass bushing and hairpin. We highly recommend that you buy and install this kit on your car. For the price, buy a spare and throw it in the glove box. You can also find these kits at some later model Mustang restoration companies.
Also, we recommend that you do not drive in OD all the time. This has been a debate in the Ford community for years, since even the owner’s manual states that OD is your “normal” driving gear. However, with both professional recommendations and personal experience under the belt, we’re very confident in telling AOD owners to bypass OD and head straight for D when driving in the city or under 45 mph. The premise behind OD is that it lets your engine spin at lower RPM’s, reducing drag and increasing gas mileage. If you drive in town a lot and the car shifts constantly between OD and third gear, you’re not saving gas, reducing drag, or saving the OD band—in fact, just the opposite occurs. This greatly weakens the OD band which is already a fairly weak piece to begin with. As a general rule, if you’ll be driving under 45 MPH for under 10 minutes at a time, lock out OD and shift into D. The OD gear should only be used for highway use, or extended driving over 45 MPH.
THINGS YOU SHOULD NEVER DO WITH A STOCK AOD TRANSMISSION
Drive without the kickdown (TV) cable attached. You will cause immediate and severe damage to the transmission.
Manually shift gears under hard acceleration. Column shifters especially. This shortens the transmission’s life, and it’s too easy to miss a gear. If you need to downshift when going down a hill, or upshift from a stop on slippery surfaces, that’s okay.
Warning Signs (C3, C5, AOD)
Unfortunately, Ford transmissions from our era usually don’t give a whole lot of warning signs before they go. In fact, they usually just go all of a sudden. If you notice that the car is not shifting into gear right away, or won’t upshift or downshift into a certain gear, that’s usually a good sign that there’s something amiss inside the transmission. Or, if you hear clunking coming from the transmission area, that’s another omenous sign. In general, anything other than normal shifting is not good and should be taken care of immediately. In a lot of cases it’s just a simple matter of changing the filter and fluid; a new filter sometimes works miracles. For C3 and C5 models, it could be something as easy as a modulator change. But for those instances where it doesn’t make any difference, you may be looking at a transmission rebuild.
Rebuilding/Replacing A Transmission (C3, C5, AOD)
Sooner or later your transmission is going to need rebuilt. Since nothing man-made lasts forever, it’s simply a fact of life that you must deal with. The unfortunate reality is that an automatic transmission rebuild from a professional trans repair shop is not cheap—plan on spending a minimum of $500, and a lot of rebuilds can go upwards of $1000. There is usually a full day’s work inside a single transmission, as there are many small parts (springs, check balls, etc.) that must be placed in their proper order. If you’ve ever seen the inside of a transmission all torn apart, you’d understand—it’s a mess in there. The actual cost of rebuild components is usually way less than the labor costs involved. Plus, since the C3, C5 and AOD are all from the same metric family of Ford transmissions, the costs are usually higher than a standard (“American”) transmission. Essentially what you’re paying for is the expertise and time of the professionals rebuilding your transmission.
So what happens if you cannot afford a rebuild? Or say your transmission has been rebuilt once and it goes out again—what to do now? As with most things that are older, eventually you’re going to need to replace the transmission. Sometimes the cost of replacing vs. cost of rebuild will have the most profound influence on your decision. But finding the right transmission can be a challenge. Here’s a chart that can help you make an informed decision, with pros and cons for each.
Relatively inexpensive. Can inspect before buying. Exact replacement in most cases. Decent selection.
Replacement transmission could also be bad—you won’t know until it’s in. Labor involved in installing (although sometimes yards will offer to install). Must return core. Limited warranty (sometimes as little as 30 days) means you must install quickly.
Transmission shop pre-rebuilt
Uses cored-in transmission for a rebuild—very cost-effective. Usually comes with warranty. Can install if needed, but you can buy outright.
Quality of rebuild components may vary. Built-in profit means this can be expensive if you don’t shop around. Must leave or return a core.
Race rebuilt transmission
All the best components. Pre-tested—all the bugs worked out. Cost can rival a professional rebuild. Decent warranty.
Expensive shipping charges. Labor involved in installing. Not intended for your average daily driver.
You will have to weigh all factors and make the best decision for yourself. For example, if you use your Cougar for daily driving only, you’ll want to look at a salvage yard or transmission shop rebuilt transmission. But if you’re hopping up your motor and need something beefier, but you don’t necessarily want to rebuild, it’s going to be more cost-effective in most cases to buy a professionally-built race transmission.
Before you do anything, though, please talk to a transmission specialist before you start the rebuild, as they may have access to similar parts at decent prices. Remember to shop around and get several estimates before making your decision. Ultimately you are in control of what happens to your transmission. Be sure you know what you’re getting into before you shell out any money!
Transmission Specialty Companies
- Baumann Engineering – Shift kits, parts, tech help
- California Performance Transmissions (formerly Art Carr Transmissions) – AOD/C4/C6/AODE parts, tech help
- Lentech – Specializing in AOD performance
- Level 10 – Kits and parts for all transmissions
- Performance Automatic – All stock transmissions and parts