Lubricant Differences

Mineral oil is used to lubricate the compressor in an R12 system. Since mineral oil is incompatible with R134a, it cannot be used in an R134a system. Synthetic oil must be used with R134a. There are different types, and not all of these are compatible. For instance, SUN PAG 56 must not be intermixed with ND-OIL8. MMSA Refrigerant Oil A993ZC1X03 may not be mixed with MMSA Refrigerant Oil A9937C1X04. Consult the under-hood label or the A/C Specifications page of the vehicle service manual for the correct oil for a particular vehicle.