Refrigerant Oil: Service and Repair

Compressor Oil Check
The oil used to lubricate the compressor is circulating with the refrigerant. Whenever replacing any component of the system or a large amount of gas leakage occurs, add oil to maintain the original amount of oil.

Checking and Adjusting Oil Quantity for Used Compressor




1. Perform oil return operation. Refer to Oil Return Operation .
2. Discharge and recover refrigerant and remove the compressor.
3. Drain the compressor oil and measure the extracted oil with a measuring cylinder.
4. If the amount of oil drained is much less than 90 cc (3.0 fl. oz. ), some refrigerant may have leaked out. Conduct a leak tests on the connections of each system, and if necessary, repair or replace faulty parts.
5. Check the compressor oil contamination. (Refer to Contamination of Compressor Oil. )
6. Adjust the oil level following the next procedure below.
7. Install the compressor, then evacuate, charge and perform the oil return operation.
8. Check system operation.

When it is impossible to preform oil return operation, the compressor oil should be checked in the following order:




1. Discharge and recover refrigerant and remove the compressor.
2. Drain the compressor oil and measure the extracted oil with a measuring cylinder.
3. Check the oil for contamination.
4. If more than 90 cc (3.0 fl. oz) of oil is extracted from the compressor, supply the same amount of oil to the compressor to be installed. If the amount of oil extracted is less than 90 cc (3.0 fl. oz), recheck the compressor oil.
5. Supply 90 cc (3.0 fl. oz) of oil to the compressor and install it onto the vehicle.
6. Evacuate and recharge with the proper amount of refrigerant.
7. Perform the oil return operation.
8. Remove the compressor and recheck the amount of oil.
9. Adjust the compressor oil, if necessary.

Checking and Adjusting for Compressor Replacement
The oil not charged in compressor (service parts). So it is necessary to charge the proper amount of oil to the new compressor.




1. Perform oil return operation.
2. Discharge and recover the refrigerant and remove the compressor.
3. Drain the compressor oil and measure the extracted oil.
4. Check the compressor oil for contamination
5. Adjust the oil level as required.
6. Evacuate, charge and perform the oil return operation.
7. Check the system operation.

Checking and Adjusting for Compressor Replacement
Unlike engine oil, no cleaning agent is added to the compressor oil. Even if the compressor runs for a long period of time (approximately one season), the oil never becomes contaminated as long as there is nothing wrong with the compressor or its method of use.

Inspect the extracted oil for any of the following conditions:
- The capacity of the oil has increased.
- The oil has changed to red.
- Foreign substances, metal powder, etc. , are present in the oil.

If any of these conditions exists, the compressor oil is contaminated. Whenever contaminated compressor oil is discovered, the receiver/drier must be replaced.

Oil Return Operation
There is close affinity between the oil and the refrigerant. During normal operation, part of the oil recirculates with the refrigerant in the system. When checking the amount of oil in the system, or replacing any component of the system, the compressor must be run in advance for oil return operation. The procedure is as follows:
1. Open all the doors and the engine hood.
2. Start the engine and air conditioning switch to ON and set the fan control knob at its highest position.
3. Run the compressor for more than 20 minutes between 800 and 1,000 rpm in order to operate the system.
4. Stop the engine.




Replacement of Component Parts
When replacing the system component parts, supply the following amount of oil to the component parts to be installed.