Front Expansion Valve

Front Expansion Valve

• 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. If the A/C compressor is switched on, the pressure on the low pressure side goes down, the expansion valve open and the refrigerant can flow of the low pressure side.

Removing

- Switch off ignition.

- Drain the refrigerant circuit.

- Remove the plenum chamber front wall.

- Disconnect the refrigerant line from the front expansion valve and put aside (do not remove), refer to => [ Front Expansion Valve Refrigerant Lines, Disconnecting ] Front Expansion Valve Refrigerant Lines, Disconnecting.

- Remove screws - A -.






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

• Seal all open lines and connections on evaporator with suitable caps (avoid dirt and moisture from entering the system).

Installing

Installation is done is reverse order, observe the following:

- Check support ring - E - for proper installation position and check the grommet in the plenum chamber rear wall for damage and proper installation.






• This figure shows the connections to the evaporator with the expansion valve removed.

- Clean the connection pipes - C - and - E - leading to the evaporator and the expansion valve connections, and check for damage.






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

• Follow the instructions for installing the O-rings. Refer to => [ Refrigerant Circuit O-rings ] Refrigerant Circuit O-rings.

- Clean refrigerant line connections on expansion valve - A - and on refrigerant lines - C - and - E -, and check for damage.

- Replace the O-rings - B - and - F -. Refer to the Electronic Parts Catalog.

- Coat O-rings with refrigerant oil before installing. Refer to => [ Refrigerant Circuit O-rings ] Refrigerant Circuit O-rings.

- Make sure the retaining plate - D - fits correctly on the connection pipes - C - and - E - leading to the evaporator.

- Tighten the screws - G -.

• Tightening specification: 10 Nm.

- Connect the refrigerant line to the expansion valve, refer to => [ Front Expansion Valve Refrigerant Lines, Disconnecting ] Front Expansion Valve Refrigerant Lines, Disconnecting.

- Evacuate and fill the refrigerant circuit.

- Install the remaining removed components.

- Check the event memory of the Climatronic control module (J255) , and erase any displayed malfunctions using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

- 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.

• Note the information regarding operating the A/C system after filling.