GM Service Manual Online
For 1990-2009 cars only

Handling R-134A

The air conditioning system contains R-134a. This is a chemical mixture which requires special handling procedures to avoid personal injury.

Always wear goggles and wrap a clean cloth around fittings, valves, and connections when performing work that involves opening the refrigerant system. Always work in a well ventilated area and do not weld or steam clean on or near any vehicle-installed air conditioning lines or components.

If R-134a should come in contact with any part of the body, flush the exposed area with cold water and immediately seek medical help.

All R-134a drums are shipped with a heavy metal screw cap. The purpose of the cap is to protect the valve and safety plug from damage. It is good practice to replace the cap after each use of the drum for this same reason.

If it is necessary to transport or carry any container of R-134a in a vehicle, do not carry it in the passenger compartment.

The refrigerant system may be evacuated and charged using an air conditioning service charging station or a manifold and gage set and a drum of R-134a 13.6 kg (30 lbs).

Before removing and replacing any of the air conditioning refrigeration lines or components, the R-134a must be completely removed from the system using an approved refrigerant recovery system.

Notice: Do not connect any line to the high-side service fitting during charging procedure.

Always use service valve and charging station equipment or pressure gage sets during evacuation and charging procedures.

Maintaining Chemical Stability In The Refrigeration System

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 the refrigerant oil. They will also affect 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 or more days, 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 the 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 the hose to the compressor with a new O-ring. For component replacement, add new Saturn refrigerant PAG oil to the component before installation.

Oil Distribution

The 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 the system during component replacement and conditions stated as follows:

With no signs of excessive oil leakage, add:

  1. Compressor: Remove, drain, and measure oil. Drain the replacement compressor. Add the same amount of new PAG compressor oil drained from the removed compressor to the replacement compressor. Refer to Air Conditioning Compressor Replacement .
  2. Evaporator: Add 67.5 ml (2.25 oz) of new PAG compressor oil.
  3. Condenser: Add 22.5 ml (0.75 oz) of new PAG compressor  oil.
  4. 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.