535I Air Conditioning.

[vping]

Now that the trans is worked out, I have to deal with the AC. It's not worked since I got it. What is the best way to DIY it and see what it's condition it's in? I've heard that it is the old R12 system and should be converted to the R134a. What are the truths to this and is there an aftermarket R134a kit I can purchase?

Cheers
Vince

[Rus]

First and foremost, go out to your car and check if your system still uses R-12. If it does, your A/C connection fittings will be threaded. R-134 fittings are a quick-release non-threaded type and are larger than R-12 fittings.

If you still have R-12 in the car, you have two options. Buy R-12 and charge it or buy R-134 and convert. I'm currently going the R-12 route. To do that you need to get certified as a MVAC technician at a place like epatest.com. Costs about 20 bucks and 1/2 hour of your time. Using R-12 is pretty simple and you'd only need gauges and freon.

Converting to R-134 is more involved. You need to get the system evacuated. Furthermore, you need to drain the oil from your compressor and possibly flush the system to remove traces of the old mineral oil from R-12. The dryer unit must also be replaced. Then you would need to add new R-134 compatible oil to your compressor, place the system under vacuum and charge it with R-134. I believe BMA has a R-134 conversion kit, but it doesn't include a dryer unit. They do include o-rings, fittings and oil though.

[Tiger]

Majority of the time, you just need top up of refrigerant. Get a gauge to see what pressure reading is.

I have done few of AC with machine and alot of the cars that came in with pressure reading actually has no or tiny refrigerant recovered.

I definitely would change out the valves for low and high side first if you decide to evacuate the system. Don't worry about compatability of oil too... if you loss pressure or refrigerant, you lost quite a bit of oil too... so most kits makes it compaitble enough.