[AwPhuch]

Refrigerant Oil: A/C systems carry oil through the system with the refrigerant to lubricate various parts such as the compressor. R-12 systems traditionally used mineral oil for this purpose, but this does not work well with R-134a. As a result, two new types of refrigerant oils emerged that are compatible with R-134a: PAG oil and POE (ester) oil. Many car manufacturers now use PAG oil in systems originally equipped with R-134a. Aftermarket companies, on the other hand, often choose ester oils for lubrication with R-134a because they tend to attract less moisture than PAG oils. This makes ester oils better suited for in-service situations. For best results, follow the exact instructions of the company supplying the retrofit kit for correct oil type and quantity.

Most AC compressors only hold at MAX 2-4 ounces of oil (around 100cc)...if you overfill with oil it creates massive overpressure and usually can destroy the compressor rather quickly...so if crack open and vacuum down the lines...you shouldnt need to add any oil..so getting those small cans from freon..DONT get the ones that have oil in them or you will kill the compressor

Oh and vacuuming the lines...all it does is create a lower pressure..and water at low pressure boils (how you can boil a cup of room temperature water in a vacuum bell)all its doing is "boiling" the water out..the longer you leave vacuumed the less "moisture" in the lines

Caution! - Always use separate refrigerant recovery, recycling and recharging
service equipment for R-12 and R-134a systems. If the same piece of
equipment is used for both R-12 and R-134a systems, residual traces
of refrigerant will contaminate and damage the equipment.
Service equipment includes recovery, recycling, recharging station,
vacum pump, manifold gauges, etc.

Caution! - Do Not Blow compressed air and nitrogen through the compressor or
expansion valve. Refrigerant circuits retrofitted to us R-134a must
not be rinsed with agent R11.

Replacement compressors are filled with nitrogen. If gas does not
escape when removing protective caps on suction and discharge ports,
assume leakage and do not install compressor.

When replacing damaged compressors, ensure existing mineral based
refrigerants oil is drained and replaced with PAG oil.

Always replace receiver drier if refrigerant circuit is left open.

Due to residual amounts of mineral based refrigerant oil in systems
retrofitted to use refrigerant R-134a, the newly installed PAG
refrigerant oil will discolor immediately after use. This is normal
and does not indicate a refrigerant related fault.

Hope that helps...I recommend having someone who knows on hand

http://www.carcare.org/Climate_Contr...ants_oil.shtml

Brian
AwPhuch