Refrigerant Oil: Service and Repair

NOTICE: Use only Polyalkylene Glycol Synthetic Refrigerant Oil (PAG) for internal circulation through the R-134a A/C system and only 525 viscosity mineral oil on fitting threads and O-rings. If lubricants other than those specified are used, compressor failure and/or fitting seizure may result.


If the refrigerant charge is abruptly lost due to a large refrigerant leak, approximately 90 ml (3 fl oz) of refrigerant oil will be carried out of the system suspended in the refrigerant.

- Any failure that caused an abrupt refrigerant discharge will experience this oil loss.
- Failures that allow the refrigerant to seep or to bleed off over time do not experience this oil loss.

When you replace a component which caused a large refrigerant leak, add the following fluids:

- 90 ml (3 fl oz) of new polyalkylene glycol (PAG) synthetic refrigerant oil (GM P/N 12345923 or equivalent)
- The required amount of oil for the particular component.

Add the oil directly to the replaced component if possible. If you cannot easily add the oil to the replaced part, add the oil to the accumulator.


You must add new oil to the system whenever you replace components, as follows:

Accumulator 90 ml
Compressor 60 ml
Condensor 60 ml
Evaporator 60 ml

NOTE: Replacement compressors do not have any oil in the compressor. Add the correct amount of oil to the replacement compressor before replacement.

Replace the accumulator when the system has been opened for an extended period of time or a physical perforation to the shell results in any of the following conditions:

- A leak
- A damaged sealing surface
- Damaged fitting threads to the inlet or the outlet lines nes