A/C Compressor, Replacing Without Needing To Clean Refrigerant Circuit

Special tools and workshop equipment required 

• Digital Scale :VAS231007 

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

• The refrigerant circuit does not have to be flushed if there is a fault in the electrically-driven A/C compressor electronics (the Control Module -- if faulty, for example) or if there is external damage after a collision. If this is the case, replace the A/C compressor without cleaning the refrigerant circuit.

-- Discharge the refrigerant circuit. Refer to REFRIGERANT CIRCUIT, DISCHARGING .

-- Remove the A/C compressor. Refer to A/C Compressor (vehicle-specific Service Information).

Vehicles without a weight indication on the data plate of the A/C compressor

-- Drain the old refrigerant oil from the A/C compressor through both connections and measure it (oil quantity ₁ ). To ensure best possible drainage, move the A/C compressor in circular motion while draining.

-- Determine the refrigerant oil quantity to be removed from the replacement part compressor (oil quantity ₂ ), as follows:

• Oil quantity ₂ = oil quantity _{label on new A/C compressor} - oil quantity ₁ - safety addition of 20 cm ³

-- Drain the refrigerant oil not needed from the replacement part compressor (oil quantity ₂ ) via the low-pressure side.

• If for example 60 cm ³ of refrigerant oil had been drained from the faulty A/C compressor and the label of the new A/C compressor specifies 200 cm ³ , then, while keeping in mind the safety addition of 20 cm ³ , 120 cm ³ refrigerant oil must be drained from the new A/C compressor.

• Since the A/C compressor cannot be completely emptied, the safety addition accounts for the quantity of refrigerant oil remaining in the A/C compressor. If this would not be done, there could be a wrong quantity of refrigerant oil in the A/C compressor.

Vehicles with a weight indication on the data plate of the A/C compressor

• The tare weight (curb weight without refrigerant oil) of the A/C compressor and the quantity of refrigerant oil in the A/C compressor are specified on the data plate of the A/C compressor.
• The quantity of refrigerant oil in the A/C compressor is given in the unit cm ³ . 1 cm ³ refrigerant oil weighs 1 g (0 oz), so for a capacity specification of 200 cm ³ , the m _{oil quantity in new A/C compressor} would be 200 g (7.1 oz), for example.

-- Determine the weight of the removed A/C compressor by using the Digital Scale :VAS231007  (m _{old A/C compressor} ).

• The A/C compressor must be clean.
• The A/C compressor must be weighted without refrigerant lines, bolts, plugs and brackets. Brackets for attaching wires remain on the A/C compressor
• Attachments which are included into the delivery package, for example brackets, must be removed.

-- Determine the remaining refrigerant oil in the old A/C compressor (m _{residual quantity of oil in the old A/C compressor} ), as follows:

• m _{residual quantity of oil in the old A/C compressor} = m _{old A/C compressor} - m _{label of old A/C compressor}

-- Determine the quantity of refrigerant oil to be drained from the replacement part A/C compressor (m _{refrigerant oil drain quantity} ), as follows:

• m _{refrigerant oil drain quantity} = m _{oil quantity in new A/C compressor} - m _{residual quantity of oil in the old A/C compressor}

-- Drain the refrigerant oil not needed from the replacement part compressor (m _{refrigerant oil drain quantity} ) via the low-pressure side.

Continuation for all vehicles

-- Assemble, evacuate and fill the refrigerant circuit. Refer to WORKING WITH A/C SERVICE STATION .