Compressor HVAC: Service and Repair

Removing And Installing V6 Air-Conditioning Compressor

Tools







Preliminary work
1. Remove engine guard.

Removing air-conditioning compressor

WARNING: Danger of injury. Safety regulations should be strictly observed when working on air-conditioned vehicles and dealing with refrigerant.







1. Remove engine cover -arrow A-.







2. Unscrew the fixing clips -a- and remove both covers -arrows B-.
3. Release the connector -arrow A- and pull off -arrow B-.







4. Release the air cleaner cover -arrows C- and pull it up and out -arrow D-.
5. Loosen clamp -arrow A- and pull suction hose off throttle housing -arrow B-.







6. Turn suction hose away to the right -arrow C-.
7. Release the breather hose -arrows D- and pull off -arrow E-.
8. Remove air filter cover with suction hose.

NOTE:
- Mark the rolling direction on the top before removing the drive belt.
- Only screw the pressure screw in far enough to remove the drive belt. Otherwise, the tensioning roller housing may be damaged.

9. Mark the rolling direction -b- on the drive belt.







10. Slacken the tensioning roller with the pressure screw (M8 x 50) -arrow c--arrow A- and remove the tensioning belt -arrow B-.
11. Unscrew fastening screw -arrow 1-.







12. Turn the pulley -arrow A-, then unscrew the fastening screws -arrows 2- and remove through the openings in the pulley.
13. Take out power-steering pump and remove from the work area -arrow B-.
14. Unscrew the fastening screws -arrows 3- and take out both refrigerant lines -arrow-.







15. Close off the connections and lines immediately using suitable plugs -b and c-, then move the lines out of the work area.
16. Release connector (for reasons of accessibility) using a suitable tool -d--arrow A- and pull it off -arrow B-.
17. Unscrew fastening screws -arrows 4 and 5- and take out the air-conditioning compressor by pulling it to the side and upwards -arrow-.







Installing air-conditioning compressor

ATTENTION:
Risk of damaging the air-conditioning compressor.
- The engine must not be started until the air-conditioning system has been filled.

NOTE:
- If the air conditioning compressor is blocked/seized up, then additional steps must be carried out to ensure the operation of the air conditioning.
- New compressors are pressurised and are filled with the required amount of oil for the refrigerant circuit.
- The remaining oil quantity in the individual components must therefore be taken into account.
- Refrigerant oil from the compressor or refrigerant oil removed by suction from a previously run air-conditioning system may no longer be used (special-category waste).

1. First, open the plugs on the high-pressure side and relieve the pressure from the compressor -b-.







2. Open the oil filler screw -6- on the compressor.
3. Empty approx. 80 cu.cm of refrigerant oil out of the compressor and into a measuring glass. The remaining quantity of oil (approx. 120 cu.cm) remains in the compressor.
4. Replace the sealing ring for the oil filler screw and tighten the oil filler screw -6-. Tightening torque: 19 ftlb.
5. Use the fastening screws from the new compressor. Replace O-rings and wet the new rings with refrigerant oil.
6. Position the bushings at the front of the compressor.
7. Position compressor in installation position -arrow- and secure with the fastening screws -arrows 4 and 5-. Tightening torque: 17 ftlb. Tightening torque: 33 ftlb.







8. Push on the connector -arrow A-, until the lug -arrow B- is felt to engage.







9. Do not remove plugs -b and c- until shortly before installation.
10. Connect the two refrigerant lines -arrows C- and screw down with the fastening screws -arrows 3-. Tightening torque: 15 ftlb.
11. Position power-steering pump in installation position -arrow A- and screw in the fastening screw -arrow 1-, but do not tighten it.







12. Turn the pulley -arrows B-, then screw the fastening screws -arrows 2- in through the openings in the pulley and tighten them. Then tighten the fastening screw -arrow 1-. Tightening torque: 19 ftlb.
13. Check installation position and direction of rotation -b- of the drive belt.







14. Unscrew the pressure screw -arrow c- and tension the drive belt -arrow-.
15. Push in breather hose -arrow A- until you feel the lugs -arrows B- engage.







16. Insert air cleaner.







17. Connect the suction hose to the throttle housing -arrow A-.
18. Fit the cover of the air cleaner housing -arrow B- into position and fasten with the retaining clips -arrows C-.
19. Tighten the clamp -arrow D-.
20. Push on the connector -arrow A-, until the lug -arrow B- is felt to engage.







21. Push on the engine cover -arrow A-, until the lugs are felt to engage.







22. Fit the covers -arrows B- and secure with the fixing clips -a-.

Information

Work steps for blocked/seized up air conditioning compressor
1. Remove desiccator from the condenser.
2. Check the desiccator for wear/chips.

If there is wear/chips:
3. Remove the refrigerant line on the compressor - condenser.
4. Clean the refrigerant line on the compressor-condenser with nitrogen or dried compressed air.
5. Replace the condenser with desiccator.
6. Install the refrigerant line on the compressor-condenser.

If there is no wear/chips:
- Replace the desiccator.

Running-in regulations for commissioning a new air-conditioning compressor

NOTE: The time specifications depend on the inertia of the temperature sensor used and can deviate from the specified times. Pay attention to the operating instructions for the temperature probe and the temperature sensor.

1. First start (first time the engine is started on vehicle)
1.1. Switch on temperature probe and position both temperature sensors. Insert the first temperature sensor centred in the right centre nozzle approximately 4 cm deep, and position the second temperature sensor on the air inlet in the footwell on the passenger's side. Temperature probe for measuring surface and air temperature NR.164
1.2. Switch on air-conditioning compressor by pressing the .ECON" key (ECON goes out in display).
1.3. Set the air conditioner to maximum cooling with the temperature sensor (LO appears in the display).
1.4. Set maximum blower speed and then reduce the blower speed 3 settings to approximately 75% using the adjusting lever.
1.5. Open the right centre nozzle.
1.6. Allow engine to run at idle speed for 2 minutes.

2. Record the temperature after another 30-60 seconds.
2.1. Read out the temperature in the right centre nozzle. There must be a temperature difference of > 14 degrees C compared to the temperature at the air inlet in the passenger's footwell.
2.2. Switch off engine.

NOTE: For the following temperature recordings, both temperature sensors must be brought to a uniform temperature level. To do this, hold both temperature sensors in front of the centre nozzle during the 4 minute idle speed phase.

3. Restarting engine
3.1. Switch off air-conditioning compressor by pressing the .ECON" key (ECON appears in display).
3.2. Allow engine to run at idle speed for 4 minutes.

4. Start recording the temperature
4.1. Switch on temperature probe and position both temperature sensors. Insert the first temperature sensor centred in the right centre nozzle approximately 4 cm deep, and position the second temperature sensor on the air inlet in the footwell on the passenger's side. Temperature probe for measuring surface and air temperature NR.164
4.2. Switch on air-conditioning compressor by pressing the .ECON" key (ECON goes out in display).

NOTE: With a 4 zone-air conditioner, the rear air conditioner must also be set to maximum cooling for both sides (LO) (if necessary, use the MONO function). To activate the MONO function, the .AUTO" -adjusting lever of the front air conditioning control must be pressed longer than 2 seconds (MONO appears in the display).

4.3. Set the air conditioner to maximum cooling with the temperature sensor (LO appears in the display).
4.4. Open the right centre nozzle.
4.5. Set maximum blower speed and then reduce the blower speed 3 settings to approximately 75% using the adjusting lever.
4.6. Hold the engine speed at a max. of 4000 rpm for 3 minutes.

5. Record the temperature after another 1-2 minutes.
5.1. Read out the temperature in the right centre nozzle. There must be a temperature difference of > 14 degrees C compared to the temperature at the air inlet in the passenger's footwell.
5.2. Switch off engine.
5.3. Then press the .AUTO" adjusting lever.

Subsequent work
1. Fill refrigerant on the air conditioner in accordance with regulations.
2. After replacing the air-conditioning compressor, the running-in regulations for commissioning a new air-conditioning compressor must be carried out.
3. Carry out function check of air conditioner.
4. Switch off the air conditioner again. Do not drive until the air conditioner has been filled.
5. Fit engine guard.