Operation CHARM: Car repair manuals for everyone.

Refrigerant Oil Addition

CAUTION: During normal A/C operation, oil is circulated through the system with the refrigerant and a small amount is retained in each component. If certain components of the system are removed for replacement, some of the refrigerant oil will go with the component. To maintain the original total oil charge, it is necessary to compensate for the oil lost by adding oil to the system with the replacement part.





1. For the A/C compressor, rotate compressor shaft six to eight revolutions while collecting oil in a clean measuring device.
- If the amount of oil drained from the old A/C compressor is between 85-142 ml (3-5 ounces), pour the same amount plus 30 ml (1 ounce) of clean Motorcraft YN-12b refrigerant oil or equivalent meeting Ford specification WSH-M1C231-B into the new A/C compressor.
- If the amount of oil that was removed from the old A/C compressor is greater than 142 ml (5 ounces), pour the same amount drained of clean Motorcraft YN-12b refrigerant oil or equivalent meeting Ford specification WSH-M1C231-B into the new A/C compressor.
- If the amount of oil that was removed from the old A/C compressor is less than 85 ml (3 ounces), pour 85 ml (3 ounces) of clean Motorcraft YN-12b refrigerant oil or equivalent meeting Ford specification WSH-M1C231-B into the new A/C compressor.

NOTE: Service A/C compressors are shipped without compressor oil.





2. For the suction accumulator/drier, drill two 13 mm (0.5 in) holes in the suction accumulator/drier cylinder and drain the oil into a calibrated container.
- The quantity of new oil to be added is the amount to match that drained from the old suction accumulator/drier plus 60 ml (2 ounces) of clean Motorcraft YN-12b refrigerant oil or equivalent meeting Ford specification WSH-M1C231-B.





3. For the A/C evaporator core, add 89 ml (3 ounces) of clean Motorcraft YN-12b refrigerant oil or equivalent meeting Ford specification WSH-M1C231-B to the suction accumulator/drier inlet tube.





4. For the A/C condenser core, add 30 ml (1 ounce) of clean Motorcraft YN-12b refrigerant oil or equivalent meeting Ford specification WSH-M1C231-B to the A/C condenser core or the suction accumulator/drier inlet tube.
5. When replacing the A/C evaporator core orifice, A/C compressor pressure relief valve, any refrigerant line or following minor repairs such as O-ring leaks and charge port leaks, add 60 ml (2 ounces) of clean Motorcraft YN-12b refrigerant oil or equivalent meeting Ford specification WSH-M1C231-B to the suction accumulator/drier inlet tube.
6. Replacement of components that do not require discharge of refrigerant and resulting oil loss, such as the A/C cycling switch and the A/C pressure transducer, do not require additional oil.