You need to know how much oil is in the compressor already. When you go to evacuate the system,(30"@45minutes), most of the oil and hopefully water will be evacuated,(BUT NOT ALL), and then re-introduced when it's charged with R-12/R-134A depending on which type is suited for your system. If you dont know how much is in there you could possibly add too much PAG oil in the system causing problems. I would drain the existing oil into a measured container, then after you find out how much is in there,(approx), re-fill it with either PAG, Ester or low viscosity oil dpending on which type of R-12/R-134A system freon you are using. There HAS to be some oil in the compressor and the O-Rings HAVE to have some oil on them during installation of the new componets. Just keep track of how much oil you pour back into the compressor, then when it is time for -recharge you can add a bit more. I like to add 2 ounces of PAG in the compressor head,(the other oil will be added during evac/recharge and should be around 6-8 ounces TOTAL for OEM Chrysler A/C Compressors) may be a bit less or more for non-chrysler compressors. I like to use Fresh Oil and new O-rings since these components are vital yet cheap and helps to eliminate potential problems. I also like the synthetic oils that are compatible with either 'carbon based freons' stay away from "freon' thats flammable! Yes, replace the reciever drier with a new one,, if there ever was a failure in the compressor it will contaminate the old RD with alloy shards and this will become lodged in the dessicant thats inside them. It's also impossible to remove all the water from it no matter how much vacum you place the system under.
Posted: 31 Aug 2009 13:51