Refrigerant Oil Addition

The FS-10 A/C compressor (19703) uses a unique high-quality refrigerant oil (F2AZ-19577-AC), Motorcraft Part Number YN-12B or an equivalent refrigerant oil meeting Ford specification WSH-M1C231-B. 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 gradually 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 a certain amount 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 are as follows:

During A/C Compressor Replacement

NOTE: The suction accumulator/drier (19C836) and orifice tube should also be replaced when the A/C 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.

1. Obtain a clean container that can also be used as a measuring device.

2. Place the disc and hub assembly on the compressor shaft so the shaft can be rotated.

   • 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 one ounce of clean Motorcraft YN-12B refrigerant oil 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 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 into the new A/C compressor.

R-134a Refrigerant Oil

 CAUTION: Do not add R-12 refrigerant oil YN-9 to an R-134a system. Also, do not add R-134a refrigerant YN-12B to an R-12 system. These two refrigerant oils are not compatible and mixing the two could result in A/C system damage.

The refrigerant oil used in an R-134a refrigerant system is a polyalkylene glycol (PAG) oil meeting Ford specification WSH-M1C231-B or equivalent. This type of refrigerant oil, Motorcraft YN-12B, was made especially for R-134a A/C systems and is not suitable for use in R-12 systems. Never use an R-134a refrigerant oil in an R-12 system.

R-12 systems require the use of a mineral-based refrigerant oil with special additives. This refrigerant oil is known as YN-9. This refrigerant oil was developed for use in R-12 systems only and is not suitable for use in R-134a A/C systems.

During Component Replacement

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

Other Refrigerant System Components

If any other component such as an A/C evaporator core orifice (19D990) or a hose is replaced, 59 ml (2 oz) additional refrigerant oil is necessary unless a hose bursts with a fully charged system. Then, the addition of refrigerant oil will be necessary with the amount to be determined by the technician. The suction accumulator/drier should also be replaced under these circumstances.