Front Expansion Valve

Front Expansion Valve

• After the A/C compressor is switched off in this vehicle, it may take a relatively long time for the pressure on the high pressure side to decrease (the expansion valve(s) is/are cold, the pressure on the low pressure side increases quickly after deactivation, the expansion valve(s) closes/close and the refrigerant can only flow slowly to the low pressure side).

• There are different versions of the expansion valve as all different refrigerant lines for the expansion valve depending on the date of production. Refer to the Electronic Parts Catalog.

Removing

- Discharge the refrigerant circuit.

- Remove plenum chamber cover.

- Remove right section of plenum chamber front wall - A -.






• Right section of plenum chamber front wall - A - is secured to vehicle by bolts - C - and - D -. A seal - E - is installed between plenum chamber front wall and vehicle body.

- If necessary, remove the Engine Control Module 2 (J624).

- Remove bolts - A - (tightening torque 10 Nm).






- Disconnect refrigerant lines - B - and - C -.

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

- Remove bolts - 1 - (tightening torque 10 Nm).






- Pull off expansion valve - 2 -.

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

Installing

Installation is carried out in the reverse order while noting the following:

- Replace O-ring seals - 4 - and - 5 -. For correct version, refer to Electronic Parts Catalog.

- Make sure that O-ring seals - 4 - and - 5 - are properly seated on connecting pipes to evaporator.

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

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

• If heat insulation is applied on the expansion valve, refer to Electronic Parts Catalog (not intended at this time), a reduction in performance may arise when heat insulation is missing or not installed correctly (modifies the set control characteristic by radiating heat).

• Retaining plate - 3 - is installed on connection pipes, check for proper fit when installing expansion valve.

- Place expansion valve - 2 - on to connections on evaporator.

- Install bolts - 1 - (tightening torque 10 Nm).

- Replace O-rings - D - and - E -. For correct version, refer to Electronic Parts Catalog.






- Check fitted pin - G - (installed in low pressure line connection or in expansion valve - F -, not installed at all connections) and sleeves - H - of refrigerant lines for damage and proper seating.

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

• Check O-ring seals for proper seating in groove - J - of respective refrigerant line

• Install refrigerant pipes such that they are not strained.

• Check installation position of refrigerant lines to expansion valve (they must not contact other components) and position and state of heat protection insulation applied to refrigerant lines if necessary (not installed on all engine types).

- Insert refrigerant lines into expansion valve.

- Install bolts - A - (tightening torque 10 Nm).

- Install remaining components.

- Evacuate and re-charge 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.