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

Special tools and workshop equipment required 

• Digital Scale:VAS 231 007  or commercially available

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

• A/C Service Station

• This procedure is used, for example, with an external damage of the A/C compressor or an electric fault at the electrical A/C compressor.
• If there is no capacity information on the new A/C compressor. Refer to TECHNICAL DATA .

Procedure 

-- Remove the A/C compressor. Refer to A/C COMPRESSOR, REMOVING AND INSTALLING .

-- Compare the type of refrigerant oil from the old and the new A/C compressor.

• If there are different types of refrigerant oil, then remove the refrigerant oil from the refrigerant circuit. In this case use the following procedure for replacing the A/C compressor. Refer to A/C COMPRESSOR, REPLACING DUE TO LEAKING OR INTERNAL DAMAGE .

Electric A/C Compressor

-- Determine the amount of refrigerant oil in the A/C compressor which is to be replaced (oil capacity ₁ ) as follows:

• Drain the old refrigerant oil from the A/C compressor via both connections into a clean container. To ensure the best possible drainage, move the A/C compressor in a circular motion when draining.
• Weigh the collected refrigerant oil using the Digital Scale:VAS 231 007  .
• Remove any refrigerant oil still in the old A/C compressor, to do this, clean the A/C compressor. Refer to MAIN WIRING DIAGRAM, ELECTRICALLY-DRIVEN A/C COMPRESSOR, CLEANING .
• Determine the amount of oil ₁ , for this, combine the weight of the drained and cleaned refrigerant oil.
• For 1 cm ³ refrigerant oil a weight of 1 g is presumed.

-- Check the drained refrigerant oil for discoloration and shavings.

• If a discoloration is determined (dark gray to black discoloration or shavings), then clean the refrigerant circuit and the A/C compressor. Refer to A/C COMPRESSOR, REPLACING DUE TO LEAKING OR INTERNAL DAMAGE .

-- Determine the refrigerant oil quantity to be removed from the new A/C compressor (oil quantity ₂ ), as follows:

• Oil quantity ₂ = oil quantity _{new A/C Compressor label} - oil quantity ₁

-- Drain the refrigerant oil not needed from the new A/C compressor (oil quantity ₂ ) via the low-pressure side.

• For example: If a total of 60 cm³ refrigerant oil was removed from the faulty A/C compressor and the label of the new A/C compressor specifies a quantity of 200 cm³ , then 140 cm³ refrigerant oil must be drained from the new A/C compressor.

Mechanically Driven A/C Compressor

-- Drain the refrigerant oil from the faulty A/C compressor and measure the quantity.

• Remove the oil drain plug from the A/C compressor. Refer to LEAKING OR DAMAGED COMPONENTS, REPLACING, EMPTY REFRIGERANT CIRCUIT EXCEPT A/C COMPRESSOR AND RECEIVER/DRYER .
• To accelerate drainage of refrigerant oil, rotate the A/C compressor by way of clutch plate of A/C clutch, for example.

-- Remove the oil drain plug from the new A/C compressor and drain the refrigerant oil into a clean container. Refer to LEAKING OR DAMAGED COMPONENTS, REPLACING, EMPTY REFRIGERANT CIRCUIT EXCEPT A/C COMPRESSOR AND RECEIVER/DRYER .

-- Fill with the new refrigerant oil via the opening of the oil drain plug again. The quantity equals the quantity removed from the faulty A/C compressor.

Tip

• For example: If a quantity of 40 cm³ was removed from the faulty A/C compressor and 100 cm³ was removed from the replacement part compressor, then a quantity of 40 cm³ must be filled into the new A/C compressor. (The quantity of refrigerant oil removed from the new A/C compressor may be used).

-- After charging the refrigerant circuit, check the installed oil drain plug for leaks. Refer to LEAKS, FINDING USING ELECTRONIC LEAK DETECTOR .

Continuation for all vehicles

-- Assemble the refrigerant circuit.

-- Charge the refrigerant circuit. Refer to REFRIGERANT CIRCUIT, CHARGING .

-- Start the A/C compressor. For this, perform the "Compressor cut-in, basic setting" function using the Vehicle Diagnostic Tester .