Refrigerant Oil: Service and Repair

Adding Oil to the System

- The oil should be replenished whenever a blown or ruptured hose is replaced, because the quick discharge causes some of the oil to be released along with the refrigerant.
- Use only PAG oil in an R-134a system (not mineral oil).
- Use only mineral oil in an R-12 system (not PAG oil).
- An R-134a compressor may seize if mineral oil is used (and vice versa).
- Add the right amount of oil into the system when replacing a major component such as the compressor, condenser, or evaporator.
- When replacing the compressor, drain the oil from the old compressor and measure the amount. Turning the clutch plate by hand helps "pump" out any remaining oil. Inject an equal amount of fresh oil.


NOTE: service compressors are shipped full of oil; this oil must be drained before the new compressor is installed.


- When replacing the condenser or evaporator, add 2 oz. of oil to the system.
- When replacing a receiver/dryer, add 1 oz. of oil to the system.
- You don't need to add any oil when replacing a hose, since hoses do not collect much oil.
- Oil can be poured directly into a new component while it is being installed.







- Oil can be added to a charged system using the Robinair 18065 oil injector and a manifold gauge set, or the injector bottle on the ACR(4) unit.







Robinair 18065 OIL INJECTOR
- Do not open the valve on the manifold gauge set high side; the injector is not designed for use with high pressure.
- Recover the used refrigerant and evacuate the system for 30 minutes.
- With the A/C system under vacuum, close the high- and low-side valves on the manifold.
- Attach the oil injector to the center hose.
- Check the oil level in the injector to make sure there is a sufficient amount of oil for the charge. Add more if necessary.
- Open the low-side valve.
- Note the oil level in the oil injector, then open the oil injector valve until the proper amount of oil is charged into the system.
- Close the oil injector valve and the low-side manifold valve.
- Unhook the oil injector from the manifold.

ACR(4) UNIT
- Recover the refrigerant and evacuate the system.
- Select the correct graduated bottle of replenishing PAG oil for the A/C system being serviced.
- Adjust the "O"-ring around the PAG oil bottle to the required oil charge level.
- Install the bottle on the oil injection system on the back of the unit.
- Open the oil injection system valve and watch the oil level change.
- Close the valve when the required amount has been pulled into the system, according to the underhood label or the specifications in the TIS.
- Cap the PAG oil bottle and replace the cover on the oil injection system.


- NOTE: Never let the PAG oil level drop below the pick-up tube. This would allow air into the A/C system.