AC Compressor

You must use specific types of lubricants for automotive air conditioning. Both 1996 and newer air conditioning systems use R134a refrigerant and require a PAG (polyalkylene glycol) compressor oil. Your compressor will suffer or be damaged if you use the wrong type or viscosity of compressor oil. However, the main reason behind the failure of a newly installed air conditioning compressor is using the wrong type of compressor oil.

However, if the compressor manufacturer approves, you can use PAO (polyalphaolefin) oil in place of some PAG oils.

CAUTION: Never use PAG oil in hybrid vehicles because it is electrically conductive. Only POE (polyol ester) oil is allowed for hybrid cars because air conditioning compressors are electrically driven and are not conductive. If you use the wrong oil, you risk electrocution due to a short circuit in the air conditioning compressor.

You can only use mineral oil in older R-12 air conditioning compressors because R-12 does not mix with R-134 refrigerant.

“Universal” air conditioning compressor oils are usually PAO-based and do not have the same viscosity as the PAG oil recommended for a specific type of compressor. This may result in insufficient lubrication and premature compressor failure.

Newer vehicles with R-1234yf air conditioning systems need a special 1234yf compressor oil recommended by the vehicle manufacturer. General Motors suggests using only GM lubricants (PAG-PSD1 #19260643 for the 2013/14 Cadillac XTS and PAG-ND12 #19299051 for the 2013 Cadillac ATS). Do not use Universal compressor oils in R-1234yf applications.

PAG Oil Recommendations for Various Compressors

Below is a list of lubricants by the compressor manufacturer. Find the manufacturer of your compressor by looking for an identification tag or label on the unit (or refer to the reference illustrations to the right and left)