Hi guys! How can you tell what refrigerant to use in a particular car's A/C system? I have a 1970 BMW that was retrofitted with an A/C system about 2008. It appears the compressor has a sticker that says 2006. Here are a couple of crappy cell phone pics. Thanks for any info. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Serveral things to consider: The fittings for R12 and R134a are different. If you have a gauge, without the car running and it isn't hot, but at the temperature of the air, take a pressure reading. R12 and R134a are different (assuming you have freon in the system). R12 at 90F will have a pressure of 99.6psi while R134a will have a presswure of 104.3 psi. You can get a table off the Internet of the temps and pressures. While these are close, you should be able to tell the difference with a good gauge. When in doubt, take it to a professional and let them take a look. Good luck.
I think your second piece of advice is best, take it to a pro. Last year the car ran nice and cool but a pulley bolt broke. I just got it fixed and the AC now blows maybe 70 degrees, lots of bubbles in the sight glass. I suppose I will take it in. Thanks for the advice!
