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What to Look For When Buying a Fox Body Mustang

By:  Connor MC  / May 29 2019
What to Look For When Buying a Fox Body Mustang

Are you considering buying a Fox Body Mustang? Here are the most important things to look out for when you're inspecting a used Fox Body.

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When purchasing a Fox Body, there are a host of concerns you want to look for. From dry, rotted belts to rusted floor pans and other common 1979-1993 Mustang problems, AmericanMuscle has the restoration parts to bring a tired Fox back to life.

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Finding the Right Fox Body

The 80s run of Foxbody Mustangs was a milestone decade for Ford. Their iconic Mustang finally surpassed the 200 horsepower plateau once again in 1985. The Fox Mustang posted some of the best sales numbers in a long time, likely due to the resurgence of actual power.

Surprisingly, Foxes remain highly desirable amongst young and less young. They are not nearly as valuable as the original pony cars from the sixties (nor do I believe they ever will be), however they are becoming a more sought after vehicle due to their relatively inexpensive and easily modifiable platform. Now, being a minimum of at least 20 years old, there will, of course, be some squeaks and rattles. How do you pick a stud from a dud? Let’s find out!

Cobra R Style Rims on a 1987-1993 Foxbody Mustang

Fox Body Mustang Buyer’s Guide Checklist

  • The body and frame—Look at the pillars by the windshield and rear quarter windows for bulges or cracks. It's a clear sign of a shifted frame
  • Rusting strut towers—Check all common areas for rust, and parts that must be replaced due to rust
  • Leaking rear main seals—Check for evidence of oil dripping down the back of the motor or transmission
  • Failing clutch cables—It will be obvious, the clutch will never disengage

What are the Trouble Spots When Buying a Fox Body Mustang?

The biggest area of concern for Fox Mustangs is the actual body and frame of the vehicle itself. Fox Mustangs (well, all Mustangs) are built with a unibody structure, meaning the car is constructed of various subframes connected by the floor pans instead of a full frame design. This in itself is not a problem. Pretty much every vehicle on the market uses a unibody design (except mainly for trucks and large SUVs) because of their weight and cost advantages. However, the factory bracing is inadequate to deal with the power of the 5.0L V8 up front. After years of abuse, it's not uncommon to see twisted frames simply because of a lack of bracing (which is also why a set of aftermarket subframe connectors are highly recommended as the first modification).

To check for this, take a look at the pillars by the windshield and rear quarter windows. Bulges or cracks are a clear sign the frame has shifted under the stress. If you don’t mind getting dirty, lie on your back and have a gander at the torque boxes, which are another notoriously weak area. The stock torque boxes are just tack welded in and often tear apart, particularly when pushing more than stock power levels. Cracks or rips in the torque boxes are not the end of the world either, but it will cost a pretty penny to have repaired. The actual kits are not the major cost, but rather it is the labor involved.

Check the alignment and spacing of the fenders and moldings (GTs in particular). Inconsistent alignment or misalignment may reveal the car was in an accident at some point, or again the frame has twisted somewhat. Another good indicator of a crash is the radiator supports. If they are misaligned, this Fox may have been involved in a fender bender.

SR Performance Black Subframe Connectors Installed on a Mustang

Are Rust and Decay Serious Issues?

With any aging vehicle, rust is always an issue. In particular, Fox Mustangs are notorious for rusting in the strut towers. When left alone, strut towers can become extremely expensive to repair, if worth repairing at all. Many a Fox Mustang has hit the scrap yard simply because they fell apart after rusting through the shock towers. A Fox with clean strut towers definitely earns a big check mark! If you do see rust, it isn’t the end of the world. There are aftermarket replacement panels out there, however expect to dish out an arm and a leg in labor costs to have it cut out and patched back in. To summarize – rust on the strut towers, tread carefully.

Of course you want to check all the other common areas as well, such as the fender wells and lips, the floor pans, around the windshield, and T-tops/sunroof (if equipped). Rust bubbling around any window opening typically means some moisture is passing through a seal somewhere, so it will need to be replaced.

Check the floors for rust or holes. Replacement floor plans are cheap but are annoying to replace. All the tack welds need to be drilled out (or somehow removed) on the original pan before putting in the new ones. Rotting floors are common on Fox Mustangs living in any of the salt belt states.

Foxbody with Rusted Floor Boards

What Issues Should You Look for with an Old Fox Body’s Motor?

After talking about some potentially serious issues with the frame, you’ll be happy to know as far as mechanics go, Foxbody equipment is pretty robust. In the event a repair is needed, it’ll probably be significantly less than most frame or body jobs.

Onward to the motor. The 5.0 is a very tough engine. When properly maintained, these things can last a long time before throwing in the towel. Leaking rear main seals seem to be a pretty common problem with these vehicles, so check for any evidence of oil dripping down the back of the motor or around the transmission. Any oil around the pan typically means a leaking oil pan gasket, or the drain plug is not tight enough. The water pumps too, for whatever reason, like to occasionally fail. A quick check to see if the shaft is not loose and the weep hole (on bottom) is dry indicates the water pump is still good to go.

It's always a good idea to bring a friend with you when checking out a used car, as another pair of eyes may notice something that you completely miss. When you do start the car, have you or your friend watch the tailpipes for any smoke or discoloration coming out.

  • Blue smoke is burning oil. It is not unusual for a high mileage engine to burn some oil, but if it is continuously puffing blue, or every time the throttle is applied, it is likely the rings are shot. In this case the engine will need a rebuild.
  • If you see white smoke out of the tailpipe, this is coolant (coolant also has a sweet smell to it). Blown head gaskets is a common cause for coolant to mix with the gas.
View of a Rear Main Seal on a Foxbody Mustang
Rear Main Seal

Transmission & Differential – What to Look For

Concerning the transmission, if it is a manual car, check that all gears engage smoothly and do not pop out (test drive needed). The clutch should engage midway down the pedal travel, not off the floor or at the top. If so, the clutch could be in need of adjustment (via the cable and clutch quadrant) or could be worn out. Speaking of clutch cables, this is another favorite item to fail on these 80s Mustangs (as well as the clutch quadrant). It will be immediately obvious if it has failed as the clutch will never disengage.

Also note: the reverse gear on T5 transmissions is NOT synchronized. Thus, if you grind the gear when going into reverse, unfortunately, this is normal. A trick to contend with this is while stopped, shift into any other gear (my favorite is 1st), wait a few seconds for everything to slow down, then shift the car into reverse.

Automatic transmissions are a little trickier to diagnose. Abrupt shifting can either be a sign of wearing components or that an aftermarket valve body has been installed. Definitely check the fluid if you can for AOD transmissions. It should be nice and red and have no burning smell to it.

Ford Racing Foxbody Clutch Cable
Clutch Cable

Fox Body Rear End Inspection

The last major drivetrain part to check is the 8.8” (or 7.5” depending on the year and trim level) differential unit. Check around the housing for leaks, which can sometimes happen. More commonly found, however, is the Trak-Lok clutches have worn out, resulting in one wheel peels. Replacement clutch packs cost around $100-$150, so not too bad.

Interior Wear - What Does It Mean?

The condition of the interior is a good indication of how the car has been treated. If the interior is meticulously tidy (no garbage, stains, etc.), more likely than not the rest of the car has received the same car (i.e. good care, regular maintenance).

Concerning the dash and instruments, check the dash for cracks. Gauges in these cars are notoriously inaccurate and frequently stop working or only work partially.

Concerning the odometer, if the numbers do not line up evenly, then most likely the odometer has rolled over. US cars only go to 99,999 miles before rolling over (Canadian versions will go to 999,999 km before rolling over). Therefore if you see the car has 13,000 mi on it and the numbers aren't quite even, most likely it has rolled over and really has 112,999 mi on it.

The horn button is frequently worn out, as is the mechanism that holds the ashtray door closed. Both of these are inexpensive and easy to fix.

Foxbody Mustang with Axial Chrome Headlights

When Shopping for a Fox Body, Nobody Wants a Lemon

Listed above are the common wear areas on these Mustangs. Of course, there is suspension and brakes too, but as with any car they will wear with mileage. I consider those two latter categories to fall under “routine maintenance and ownership costs.” As stated, these Foxbody Mustangs are pretty stout and can last a long time. Frame and body should be the first priority as pretty much anything else mechanical can be fixed within a reasonable cost.

At the end of the day, the decision is all yours. Do you like the car? What do you like about it? What don't you like about it? What needs to be fixed, and what doesn't? All of these factors play into what your final offer may be. Just keep in mind priority #1 is the frame, priority #2 the body, and everything else after those two. All other mechanical components can be fixed or swapped, in my opinion, with relative ease (I'd rather turn a wrench than operate a sander).

Also, be realistic. At best, the Foxbody you're looking at is a minimum of 20 years old. Any 20-year-old car is going to have some wear and tear, squeaks and groans. Factor in that you're looking at a Mustang, which probably has seen at least one or two owners over the years with a heavy foot. You cannot expect a flawless vehicle. If you want new, buy new. It is very frustrating as a seller to be dealing with buyers who expect a flawless car for $4000.

Most importantly, always verify the owner's claims by asking for receipts or any type of legitimate paperwork that can attest to the history of the car. If the seller is claiming the car has brand new aluminum heads on it that should be easy to see. A receipt in this case is icing on the cake, but you should easily be able to confirm if the heads are aluminum or not. Now, what if the seller is claiming the stock heads have been ported and polished, or the motor was recently rebuilt? I would expect to see the bills for this. It is very common to hear a certain component has been replaced or rebuilt, but there is no bill for it because "the previous owner did it". You know the old saying, talk is cheap...

What About the Fox Body GT and LX? What's the Difference?

In the long run, not much. Depending on the options from the factory, the LX model could be up to 50-250 pounds lighter than the GT. The LX also doesn't have the same ground effects as the GT model. From the factory, the GT was offered with more options as standard whereas the LX came as a blank slate. In fact, the only option you couldn't get on the LX from Ford was fog lights. However even if you go with an LX model, you can add fog lights at a later date. The wiring harness is designed to make fogs an easy addition.

What About Other Submodels?

Foxbodies, while all looking somewhat similar, had many variations throughout production. These ranged from trim changes ‚Äčto entire engine modifications. From 1979-1985 the 5.0s were carbureted, and from 1986-1993 they were fuel injected. Camshafts were changed in 1982, 1985, and 1989. From 1979-1986, four lights were utilized up front (commonly known as four-eyed models). In 1987, they were changed to the traditional two light system. In 1991, a revised convertible top was utilized and varies from previous years. This also rendered a change in the grille insert and front fascia.

Importing a Foxbody and Passing Inspection

Frequently, the perfect car is found out of state or out of province (in Canada's case). At least for me it was. Anyways, quite often when you buy a car not registered in your district, it will have to undergo some sort of safety inspection before it can be registered in your area.

When examining a car out of state, here are some key things to notice.

  • Brakes are working smoothly, braking power evenly distributed
  • Working e-brake or parking brake
  • Undamaged windshield or hatch glass (no cracks)
  • All exterior lights work correctly and are clearly visible when illuminated
  • Headlights, tail lights, flashers, brake lights
  • Side view and rear view mirror are present, in the correct place and firmly attached
  • If it is a manual transmission, the car will not start unless the clutch is depressed
  • Functional horn
  • Steering is tight and properly aligned
  • No visible fluid leaks
  • Good tires & tire tread
  • If you have to pass emissions:
    • Catalytic converters are present
Fitment includes: 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, GT, Cobra, LX, SVO