Originally Posted By: willbur
Greetings-
Its that time of year again and my AC is blowing warm air. I need to add some Freon. My question concerns adding PAG compressor oil along with the Freon. Is this necessary if only a small(?) quantity of Freon will be added, and I did not notice any oil staining around the compressor? The compressor mag. clutch does not engage. Electrical control components check out.
if the compressor clutch never engages when you turn the ac on, then it sounds like you had a massive leak and you are below 30psi in the system which is where the low pressure cut off switch disengages the compressor clutch. normally you should have over 70 psi in the system, depending on temperature. Once you start reading a static pressure below 70 psi with the car off and ambient temperature above 60°F you have lost a lot of refrigerant. you're options are (a) as long as no oil staining found anywhere keep recharging it with plain r134a refrigerant only no additives no oil and live with the leak, or (b) find and fix the leak. the leak can be at the high/low service schraeder valves, at a connection where there's an o-ring or where a pipe turns into a rubber flex hose at that crimp, or through the compressor shaft seal. ask some ac shops if they have a ac leak detector they can use to pinpoint where r134a is escaping for a few bucks, and decide on service.
you mention freon and pag oil...
like was mentioned freon is R-12 which uses mineral oil not PAG oil.
R134-a uses PAG oil, not mineral. I assume you have an r134a system.