F 150 Heritage 4WD Pickup V8-5.4L CNG VIN M (2004)
Accumulator HVAC: Service Precautions
CAUTION: Refrigerant Compressor Oil (Mineral Oil) F73Z-19577-AA (Motorcraft YN-9-A) should be used to lubricate R-134a refrigerant
system O-ring seals only and should not be added to the R-134a refrigerant system as an A/C compressor lubricant. PAG Refrigerant
Compressor Oil F7AZ-19589-DA (Motorcraft YN-12-C) or equivalent meeting Ford specification WSH-M1C231-B only should be used as an
A/C compressor lubricant.