COOLING OFF. PERIOD. Original Air has the solution to your Fox’s wimpy A/C. COOLING OFF. PERIOD. Original Air has the solution to your Fox’s wimpy A/C.
By Marc Christ | Photos by Dominga Weicht
The Fox-body Mustang has become the new ’32 Ford, the original hot rod, in that you can almost build one from parts from the ground up. Almost every piece of the engine, transmission, interior, suspension, rearend, and brakes are available. Many Fox owners take advantage of the smorgasbord of parts offered, but for some reason, the A/C system often gets overlooked.
Classic Auto Air’s Original Air Group offers this ’87-’93 engine compartment upgrade kit (22-132) for $775. We’ll just call it an underhood kit. It comes with the Sanden-style compressor, micro-tube condenser, accumulator, orifice tube, and everything needed for proper installation, minus refrigerant. As you can see, Jason’s Fox is stock! It’s a shame to upset its originality, but it’s for a good cause. Here you can see the “retrofit kit” fittings that someone installed along the way. This is not the proper way to upgrade your Mustang’s A/C system to R-134a. After having what was left of the old refrigerant evacuated properly at a local A/C shop, we began by removing the original hoses. A good list of open-end wrenches to have on hand are 5/8, 11/16, 3/4, 7/8, and 1-1/16.
After removing the compressor, we then removed the big black mounting bracket. It needs to be modified to accept the new compressor. Here, Jason is cutting off a large portion of the bracket to provide a nice, clean installation. You don’t have to cut this much off, but it sure makes the install look nicer. We went ahead and cleaned it up and gave it a fresh coat of black before reinstalling it. Then, we removed the upper radiator mounting brackets. We cleaned them up while they were off as well. Using disconnect tools, we removed the lock-hose connections at the condenser. Then we removed the two bolts in the upper condenser mounts, pushed the radiator toward the engine, and slipped the condenser out. The instructions tell you to drain and remove the radiator, so it may be necessary on some models. We managed without that step.
The factory R-12 condenser (left) utilizes a tube-and-fin design, which is not efficient enough for R-134a refrigerant. The new, direct bolt-in condenser included in the kit (right) utilizes a high-performance parallel-flow condenser. You can see how many more tubes are in the new one, allowing the refrigerant to make more passes over the coils. We then removed the accumulator, suction hose, and liquid line from the evaporator. It is very important to be careful when removing these fittings! One is a spring-lock fitting, and the other is a screw-on, O-ring fitting. If you’re too aggressive in the removal of either of these fittings, you could damage the evaporator and will have to pull the dash to replace it. Think about that. We then flushed the evaporator core (twice). You can buy a fancy flush kit at your local auto parts store, but denatured alcohol works great and is available at your local hardware store. We installed the new condenser in the stock location using the factory hardware and reinstalled the radiator mounting hardware. The kit comes with compressor mounting brackets, which adapt your factory mounts to the new compressor. Bolts, nuts, and washers are included. The hoses that come with the kit are already made the correct length and all come with O-ring fittings and plenty of O-rings to do the job. There’s even some oil in the kit to lubricate the O-rings before installation. Here, the accumulator is ready for installation with a new (included) high/low pressure sensor installed.
We installed the new accumulator. It’s a direct bolt-in piece, utilizing the original mounting hardware and wiring. Then we installed the remainder of the hoses. Be careful not to over tighten them, as it’s very easy to damage the O-rings. In order for the compressor clutch to engage when it’s required, the compressor feed wire has to be attached. The stock compressor uses a feed and a ground wire, while the new compressor only requires the feed wire. The solid black wire will be the ground, so the other wire will be the feed. Ours was black with a yellow stripe. We installed the included female bullet connector onto the compressor feed wire and connected it to the compressor.
Once all of the fittings were tightened, we attached our vacuum pump. It’s necessary to pull a vacuum on the system in order to remove all the moisture that may have gotten into the system during installation. It will also remove any other contaminants that may remain, like remnants of the denatured alcohol. We left ours on for 45 minutes, but 30 minutes is enough time. This is also a good time to check for leaks. Once the system is holding a good vacuum, simply close the valves on the gauge set and watch the gauges. If they don’t move, then the system is holding a vacuum and probably won’t leak. In order to determine how much R-134a is required, you must first know how much R-12 the original system called for. Ours called for 2 pounds, 10 ounces, or 42 ounces. A good rule of thumb is to install 75 percent of R-134a as the system calls for. And since a can of refrigerant is 12 ounces, we decided to go with 2.5 cans, or 30 ounces. The compressor mount is clean and low-profile, and the belt aligns perfectly.
But the most important part is how cool the air is coming out of the vents. The results? 40 degrees!