Adding Refrigerant Oil

Each compressor uses a special refrigerant oil (Motorcraft YN-9). This oil contains special additives not found in most refrigerant oils. It is important that only the specified type (YN-9) and quantity of refrigerant oil be used in the compressor. Refer to the applicable compressor section. If there is surplus oil in the system, too much oil will circulate with the refrigerant, reducing the cooling capacity of the system. Too little oil will result in poor lubrication of the compressor.

When it is necessary to replace a component of the refrigeration system, the correct procedures must be followed to ensure that the total oil charge in the system is correct after the new part is installed. During normal A/C operation, some refrigerant oil is circulated through the system with the refrigerant and some is retained in the compressor. 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. Refer to the applicable Compressor Section for the procedure to replace lost oil, unless a hose has been damaged and the refrigerant escaped at a rapid rate.

NOTE: Replacement of other refrigerant system components such as hoses, compressor valves, pressure switches, etc. does not require the addition of refrigerant oil unless a hose has been damaged and the refrigerant escaped at a rapid rate.