Operation CHARM: Car repair manuals for everyone.

Maintaining Chemical Stability

The efficient operation and life of the air conditioning system is dependent upon the chemical stability of the refrigeration system. When foreign materials, such as dirt, air, or moisture, contaminate the refrigeration system, they will change the stability of the R-134a and viscosity of refrigerant oil. They will also effect pressure-temperature corrosion and abnormal wear of moving parts.

If the A/C system is opened to the air for a significant amount of time (two days or more) due to a missing component or opened refrigerant line, the receiver-dehydrator should be replaced.

Adding Oil
Adding oil to the A/C system should take place after recovery and before evacuation procedure. Remove the refrigeration discharge hose at the compressor pipe connection. Pour the correct quantity of new PAG compressor oil into the discharge hose pipe. Always lubricate new O-rings with clean R-12 mineral compressor oil prior to assembly. Then properly connect hose to compressor with new O-ring. For component replacement, add new Saturn refrigerant PAG oil to the component before installation.

Oil Distribution
Saturn air conditioning system requires 150 ml (5.07 oz.) of PAG compressor oil. Service compressors have 65 ml (2.20 oz.) of PAG oil installed.

New oil quantities must be added to system during component replacement and conditions stated as follows:

With no signs of excessive oil leakage, add:
A. Compressor: Remove, drain, and measure oil. Drain replacement compressor. Add the same amount of new PAG compressor oil drained from removed compressor to replacement compressor. See Compressor section for details.
B. Evaporator: Add 67.5 ml (2.25 oz.) of new PAG compressor oil.
C. Condenser: Add 22.5 ml (0.75 oz.) of new PAG compressor oil.
D. Receiver-dehydrator: Add 30 ml (1 oz.) of new PAG compressor oil.

Refrigerant Oil Loss Due To A Large Leak
If the refrigerant charge is abruptly lost due to a large refrigerant leak, (hose rupture or collision) approximately 90 ml (3 oz.) of refrigerant oil will be carried out of the system suspended in the refrigerant. Any failure that caused an abrupt refrigerant discharge will cause this oil loss. Conditions that allow the refrigerant to seep or bleed off over time do not cause this oil loss.

Upon replacement of a component which caused a large refrigerant leak, add 90 ml (3 oz.) of new PAG compressor oil plus the required amount of oil for the particular component (as outlined previously).

Add the oil directly to the replaced component if possible. If the oil cannot easily be added to the replaced part, add the oil to the compressor discharge port side hose (as outlined previously).