Expansion Valve

Expansion Valve

Special tools, testers and auxiliary items required

• Engine Bung Set (VAS 6122)

• After switching off the A/C compressor in this vehicle, it may take a relatively long time for the pressure on the high pressure side to decrease. This is because the expansion valve is cold and the pressure on the low pressure side increases quickly after shutting the compressor off, then the expansion valve closes and the refrigerant flows slowly to the low pressure side.

Removal






- Remove the tower brace.

- Drain the refrigerant circuit.

- Remove the refrigerant lines from the inner heat exchanger. Refer to => [ Refrigerant Lines at Inner Heat Exchanger, Disconnecting and Connecting ] Refrigerant Lines at Inner Heat Exchanger, Disconnecting and Connecting.

- Expose the inner heat exchanger - 1 - at the bracket by releasing the clip - 5 - - arrow - and open it.

- Remove the bolts - 3, 4 -.

- Disconnect the refrigerant tube - 2 - with the inner heat exchanger from the expansion valve.

- Seal open lines and connections with a clean plug from the (VAS 6122).

- Remove screws - A -.






- Disconnect the expansion valve - B - from the refrigerant lines leading to the evaporator.

- Seal open lines and connections with a clean plug from the (VAS 6122).

Installation






Installation is done is reverse order, observe the following:

• Tightening specification, refer to => [ Refrigerant Lines, Condenser, Expansion Valve, A/C Compressor Overview ] Refrigerant Lines, Condenser, Expansion Valve, A/C Compressor Overview.

- Replace the O-ring seals. Refer to Electronic Parts Catalog (ETKA).

- Insert the O-ring seals - B, F - at the connecting pipes - C, E - to the evaporator.

• Expansion valve is available in different versions (same housing but a different control characteristic), therefore ensure the exact allocation. Refer to Electronic Parts Catalog (ETKA).

• Coat the O-ring seals lightly with refrigerant oil prior to installation. Refer to => [ Refrigerant Circuit O-rings ] Refrigerant Circuit O-Rings.

• Check the refrigerant pipes to the evaporator for contamination and damage.

• Ensure proper seating of the O-ring seals on the evaporator connecting pipes.

• If heat protection insulation - 2 - is missing or not installed correctly, it can cause reduced performance of the A/C system (change of adjusted control characteristic of expansion valve due to heat radiation).

- The retaining plate - D - must sit on the connecting pipes as shown in the figure.

- Install the expansion valve - A - on the evaporator.

- Tighten the screws - G -.

- Install the refrigerant tube with inner heat exchanger. Refer to => [ Refrigerant Tube with Inner Heater Exchanger ] Refrigerant Tube With Inner Heater Exchanger.

- Attach the refrigerant lines to the inner heater exchanger. Refer to => [ Refrigerant Lines at Inner Heat Exchanger, Disconnecting and Connecting ] Refrigerant Lines at Inner Heat Exchanger, Disconnecting and Connecting.

- Install the suspension tower brace.

- Evacuate and fill the refrigerant circuit.

- Operate the A/C system after filling the refrigerant circuit. Refer to => [ A/C System, Operating After Filling Refrigerant Circuit ] A/C System, Operating After Filling Refrigerant Circuit.

After completion of the repair work, perform the following work on the control head using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function:

- Query the event memory and erase any displayed entries.