Refrigerant Oil: Service and Repair

Filling And Adjustment Of Compressor Oil

The A/C system is filled with 145 ml compressor oil. A certain amount of compressor oil is always lost while draining the refrigerant and when replacing components. This amount must be refilled, otherwise the function of the system will deteriorate.

Compressor oil should be filled on the high pressure side or through the oil plug.

IMPORTANT: Use the specified compressor oil.

When the refrigerant is drained the compressor oil is also drawn off. When the compressor oil is filled a quantity of tracing agent must be added to facilitate leakage detection. This does not apply in the cases when a new receiver is fitted as it already contains tracing agent.

The table below shows how much compressor oil is lost in connection with various types of work on the A/C system:

Reason for loss of oil Amount of oil lost
Draining refrigerant 15 ml
Draining refrigerant 15 ml
Replacement of hose 15 ml
Replacement of condenser 30 ml
Replacement of evaporator 30 ml
Replacement of receiver 30 ml
Replacement of expansion valve 15 ml
Replacement of compressor* 50 ml*

* Note that the new compressor contains 145 ml of oil when delivered. In order to avoid getting too much oil in the A/C system, thereby reducing cooling performance, the oil must be drained before the compressor is fitted. How much needs to be drained depends on how much oil has been lost in conjunction with any other component replacements. The A/C system must always contain 145 ml of compressor oil.

If just the compressor is replaced, 80 ml oil must be tapped from the new compressor (145-50-15=80). This replaces the 65 ml of oil lost (145-80=65).

If the receiver or the like is also replaced, only 50 ml of oil must be tapped from the compressor based on the following calculation:

145 ml (new compressor)
- 15 ml (lost during draining)
- 30 ml (lost when replacing receiver)
- 50 ml (lost when fitting a new compressor)
- 50 ml (lost when fitting a new compressor)

Tightening torques:
Compressor oil plug 30 Nm (22 lbf ft)