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Refrigerant Oil Addition

The R-134a A/C system FS-10 A/C compressor uses a unique high-quality refrigerant oil, Motorcraft Part Number YN-12b or an equivalent refrigerant oil meeting Ford specification WSH-M1C231-B. An oil charge of 207 ml (7 oz.) is used in a new system. 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 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 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.

FS-10 compressors shipped as service replacements MAY or MAY NOT contain oil.

The procedures for replacing oil are as follows:

During A/C Compressor Replacement
1. Prior to installing the replacement A/C compressor, drain the refrigerant oil from the removed A/C compressor into a clean calibrated measuring device.

To drain the oil, place the disc and hub assembly on the old compressor shaft so the shaft can be rotated.

Rotate the shaft by hand six (6) to eight (8) revolutions while pouring the oil from the ports. This effectively empties the A/C compressor of oil.

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

2. Record the amount of oil removed from the old A/C compressor.
3. If the new FS-10 A/C compressor contains oil, drain the refrigerant oil from the new A/C compressor following the procedure in Step 1 above.

If the new FS-10 A/C compressor HAS NO oil, then the oil draining step will not be necessary.

4. Matching oil quantities:

If the amount of oil drained from the old A/C compressor (Step 2) is between 85 and 142 ml (3 and 5 oz.), pour the same amount of clean YN-12b refrigerant oil into the NEW A/C compressor.

If the amount of oil drained from the old A/C compressor (Step 2) is greater than 142 ml (5 oz.), pour 142 ml (5 oz.) of clean YN-12b refrigerant oil into the NEW A/C compressor.

If the amount of oil drained from the old A/C compressor (Step 2) is less than 85 ml (3 oz.), pour 85ml (3 oz.), of clean YN-12b refrigerant oil into the NEW A/C compressor.

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