Refrigerant Oil Addition

The FS-10 A/C compressor (19703) uses a unique high-quality refrigerant oil (for R-134a systems F2AZ-19577-AC), Motorcraft Part Number YN-12B or an equivalent refrigerant oil meeting Ford specification WSH-M1C231-B. A new replacement A/C compressor is shipped with no refrigerant oil. It is extremely important that only the specified type and quantity of refrigerant oil be used in the FS-10 A/C compressor. If there is a surplus of oil in the system, it will circulate with the refrigerant, reducing the cooling capacity of the system. Using too little oil or oil not meeting the Ford specification will result in poor lubrication of the A/C compressor.

When replacing a component of the refrigerant system, the procedures in this section must be followed to ensure that the total oil charge in the system is correct after the new part is installed.

When the A/C compressor is operated, oil quickly leaves the A/C compressor and is circulated through the system with the refrigerant. Eventually, a balanced condition is reached in which a certain amount of oil is retained in the A/C compressor and the majority of oil is continually circulated. If a component of the system is removed after the system has been operated, some oil will go with it. To maintain the original total oil charge, add oil as required to the new replacement part.

The procedures for replacing oil follow.

During A/C Compressor Replacement

NOTE: The suction accumulator/drier (19C836) and A/C evaporator core orifice (19D990) should also be replaced when the compressor is replaced.

A new service replacement FS-10 A/C compressor contains no refrigerant oil. Prior to installing the replacement A/C compressor, drain the refrigerant oil from the removed A/C compressor into a calibrated container. The shaft should be rotated about six to eight revolutions while pouring the oil from the ports. This effectively empties the A/C compressor of oil.

• If the amount of oil drained from the old A/C compressor was between 85 and 142 ml (3 and 5 oz.), pour the same amount (plus 1 (one) additional 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 oz.), pour 142 ml (5 oz.) 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 refrigerant oil that was removed from the old A/C compressor is less than 85 ml (3 oz.), pour 85 ml (3 oz.) of clean Motorcraft YN-12B refrigerant oil or equivalent meeting Ford specification WSH-M1C231-B into the new A/C compressor.

During Component Replacement

NOTE: Cap all open refrigerant lines and components to prevent entry of dirt and moisture into the A/C system.

When replacing other components of the air conditioning system, measured quantities of the specified refrigerant oil should be added to the component to ensure that the total oil charge in the system is correct before the system is operated.

Clean refrigerant oil should be poured directly into the replacement components as follows:

• A/C evaporator core (19860): add 90 ml (3 oz.).
• A/C condenser core (19712): add 30 ml (1 oz.).
• Suction accumulator/drier: drain oil from removed accumulator/drier. Add same amount plus 60 ml (2 oz.) of clean refrigerant oil to new suction accumulator/drier.

If any other component such as an A/C evaporator core orifice or a hose is replaced, an additional 59 ml (2 oz.) refrigerant oil is necessary unless a hose bursts with a fully charged system. Then, the addition of refrigerant oil may be necessary with the amount to be determined by the technician. The suction accumulator/drier should also be replaced under these circumstances. Add an additional 59 ml (2 oz.) refrigerant oil to a system with a refrigerant leak.