Hello 1st gen community,

As you guys know, I live in Texas and the summer heat is creeping in soon. I am entirely new to the rotary world but I am determined to learn things slowly, step by step, by myself (as much as possible).

I have an '85 GS with an AC that does not blow cold at all. I mean with the heater on it heats up the inside faster. The fan works but it does not blow cold air. I can't keep the windows up for a few minutes!

I've seen a few discourse here about R12 vs R134a and I am seeing so many different opinions on which route to go. Now that it's 2025, what is the best/optimal way of making the air cold again? I would appreciate any tips and maybe some parts that I haven't checked that are working or not.

Many thanks!

 

R12 is the refridgerant type that came in the car originally. Since then, environmental concerns have outlawed it. It's still out there, if you know someone who has a stash, but you won't be able to go to a shop and have it serviced with R12 anymore.

R134a is what the standard automotive refrigerant is now. To use it, all the O-rings in your hose connections will need to be updated with HNBR (nitrile or green) O-rings which are compatible with R134a.

Basically, your system is 40 years old. A lot could have gone wrong by now, but it's most likely low or has no charge (pressure) in the system now to generate any cold air. The reason why is the big question. Was it a burst hose or a gradual leak? From where? Could be a hose connection, pin hole in the evaporator or condenser or even the shaft seal on the compressor. Whoever works on the system will need to find and address these questions.

You might check to see if the compressor pulley engages when you turn the A/C switch on, and disengage when you turn the switch off? If so, thats good because you'll know the electrical harness and compressor is still working.

Without getting too specific, you start the repair by disconnecting all the hoses, there are 4 of them. Blow and flush them out and inspect the hoses and connections for cracks and imperfections. It's a good idea to remove the condenser and compressor too. Drain any old remaining oil from both of them and flush them as well. The idea here is to clean as much of the old oil from the system as you can. While your at it, throw away the old dryer and purchase a new one.

From here, re assemble it all using new O-rings and filling the compressor with fresh oil of the correct type. Using a set of A/C gauges and a vacuum pump, evacuate the system (place the system under a vacuum) and hold it there for 30 minutes or so, to check and verify that your entire system is intact and leak free. If you can't hold a vacuum, you need to start looking for where or what part of the system is leaking. Once its all secure and solid, you re-charge the system with refrigerant.

Sounds simple, but there is some work to it and knowledge with what your working with. There are also a few threads on the forums here about using R-154 as a refrigerant. The procedure is the same, you just have to use the correct oil and O-rings that are compatible with what refrigerant you are using.(note: 79 and 80 systems don't use O-rings, they use flare type fittings)