Compressor HVAC: Service and Repair
WM 873419 Removing and installing air conditioning compressor
Tools
Technical values
Preliminary work
1. Place protective covers on the vehicle to avoid damaging the body and passenger compartment.
2. Drain refrigerant for air-conditioning system with one air-conditioning unit. -> 870317 Draining and filling in refrigerant - section on "Draining" Service and Repair
3. Remove hood compartment lid and hinges. -> 619019 Removing and installing hood compartment lid - section on "Removing" 619019 Removing and installing hood compartment lid
4. Disconnect the battery. -> 2X00IN02 Work instructions after disconnecting the battery Work Instructions After Disconnecting the Battery
5. Remove resonance tube. -> 247419 Removing and installing resonance tube - section on "Removing" Service and Repair
6. Remove oil separator. -> 10551950 Removing and installing oil separator - section on "Removing"
7. Release drive belt. -> 137819 Removing and installing drive belt - section on "Removing" Service and Repair
Removing air conditioning compressor
Installation position of air conditioning compressor
1. Loosen junction point for terminal 30 line in the engine compartment.
1.1. Loosen the two fastening nuts -1-.
1.2. Remove junction point for terminal 30 line and the two spacer sleeves -2- and lay them and the connected lines aside.
Loosening junction point for terminal 30 line in the engine compartment
2. Pull off positive crankcase ventilation hose at the oil filler neck.
2.1. Release and pull off plug-in coupling -arrow-.
2.2. Lay positive crankcase ventilation hose aside.
Pulling off positive crankcase ventilation hose at the oil filler neck
3. Loosen holder for refrigerant lines.
3.1. Screw off fastening nut -1-.
3.2. Open the holder -2- and remove the rubber sleeve -3-.
Loosening holder for refrigerant lines
4. Disconnect plug connection for air conditioning compressor.
4.1. Release -arrow A- and pull off -arrow B- connector.
4.2. Pull plug-in coupling out of the holder -arrow C-.
Disconnecting plug connection for air conditioning compressor
5. Loosen air conditioning compressor.
5.1. Unscrew the three fastening screws -1-.
5.2. Remove the holder -2- ( -arrow- ).
Loosening air conditioning compressor
6. Remove air conditioning compressor.
6.1. Carefully pull the air conditioning compressor forward in -direction of arrow- until the refrigerant lines are easily accessible.
6.2. Unscrew the fastening screws -1- , pull out the refrigerant lines and close them off immediately using suitable stoppers.
6.3. Remove air conditioning compressor in -direction of arrow-.
Removing air conditioning compressor
Installing air conditioning compressor
CAUTION
Oil fill level too low
- Risk of damage to components
-> Do not start engine.
-> Do not tow the vehicle.
Information
- 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. If a new compressor is installed, first correct the refrigerant oil quantity in the air conditioning compressor.
2. Replace O-rings for the refrigerant lines and wet the new rings with refrigerant oil.
3. Install air conditioning compressor.
Installing air conditioning compressor
3.1. Fit air conditioning compressor in -direction of arrow-.
3.2. Remove stoppers from the refrigerant lines and connections on the air conditioning compressor.
3.3. Connect air conditioning lines and secure with the fastening screws -1-. => Tightening torque: 20 Nm (15 ftlb.)
Information
Check that the line is routed correctly -arrow- to avoid damaging the line.
Line routing for air conditioning compressor
3.4. Place air conditioning compressor in installation position.
4. Secure air conditioning compressor.
4.1. Place holder -2- in installation position -arrow-.
4.2. Tighten the three fastening screws -1-. => Tightening torque: 23 Nm (17 ftlb.)
Securing air conditioning compressor
5. Connect plug connection for air conditioning compressor.
5.1. Slide plug-in coupling into the holder -arrow A-.
5.2. Plug in the connector -arrow B- until it engages securely.
Connecting plug connection for air conditioning compressor
6. Secure holder for refrigerant lines.
6.1. Insert rubber sleeve -3- and close the holder -2-.
6.2. Tighten fastening nut -1-.
Securing holder for refrigerant lines
7. Connect positive crankcase ventilation hose to the oil filler neck.
7.1. Place positive crankcase ventilation hose in installation position.
7.2. Connect the hose until the plug-in coupling -arrow- engages securely.
Connecting positive crankcase ventilation hose to the oil filler neck
8. Secure junction point for terminal 30 line in the engine compartment.
8.1. Position junction point for terminal 30 line in installation position.
8.2. Insert the two spacer sleeves -2-.
8.3. Tighten the two fastening nuts -1-. => Tightening torque: 10 Nm (7.5 ftlb.)
Junction point for terminal 30 line in engine compartment
Checking refrigerant oil in "new" air conditioning compressor
Correct the refrigerant oil level in the "new" air conditioning compressor
NOTICE
Too much or too little refrigerant oil in air conditioning circuit
- Reduced cooling output
- Lack of lubrication and failure of the air conditioning compressor
-> If a new air conditioning compressor or a component in the circuit is replaced, the oil quantity must be checked and adjusted.
Information
All connection points must be completely dirt-free.
The air-conditioning compressor must be dry (washing the vehicle) and the air-conditioning compressor and lines must be free of moisture.
The connection points must be closed after they have been opened. Use the original transport caps.
A clean measuring cylinder with a capacity of approx. 300 ml is required.
Determining oil quantity on the "old" air conditioning compressor
1. First, open the cap on the high-pressure side and relieve the pressure from the compressor -A-.
Caps
2. Open the oil filler screw -B- on the compressor.
3. Fill the refrigerant oil from the air conditioning compressor into the measuring cylinder. Turn the pressure plate on the air conditioning compressor (not the belt pulley) when emptying the refrigerant oil.
The amount of refrigerant oil is referred to as "Vold" in the formula below.
4. Always replace the sealing ring for the oil filler plug.
5. Screw oil filler plug -B- into the compressor. => Tightening torque: 30 Nm (22 ftlb.)
Determining oil quantity on the "new" air conditioning compressor
Oil filler screw
1. To drain refrigerant oil:
1.1. First, open the cap on the high-pressure side and relieve the pressure from the compressor -A-.
1.2. Open the oil filler screw -B- on the compressor.
1.3. Drain the refrigerant oil from the air conditioning compressor.
The refrigerant oil must not be re-used, but must be disposed of properly.
2. To determine the refrigerant oil quantity:
2.1. Vtotal = "Vremoved" + "Vold" + 20 cm3
2.2. Vtotal= Total volume for the new air conditioning compressor
2.3. Vremoved = Volume of refrigerant oil removed by suction
2.4. Vold = Volume of refrigerant oil in the old air conditioning compressor
2.5. 20 cm3 = Additional safety volume
3. To fill the air conditioning compressor:
3.1. Fill the determined refrigerant oil volume Vtotal into the air conditioning compressor.
3.2. Always replace the sealing ring for the oil filler plug.
3.3. Screw oil filler plug -B- onto the compressor. => Tightening torque: 30 Nm (22 ftlb.)
3.4. Install air conditioning compressor.
Work steps for blocked/seized up air conditioning compressor
1. Remove desiccator. -> 875519 Removing and installing desiccator - section on "Removing" Service and Repair
2. Check the connections at both condensers, at the desiccator and at the refrigerant lines for the desiccator for any wear/chips.
If there is wear/chips:
3. Unscrew the refrigerant line between the compressor and condenser at the connection points on the compressor and on the condenser and disconnect it. -> 874319 Removing and installing compressor-condenser line - section on "Removing" 87431903 Removing and installing compressor-condenser line in area of engine
WARNING
Acetone is a highly inflammable, irritating and combustible fluid.
- Highly inflammable.
- Irritates the eyes.
- Repeated contact can cause chapped and cracked skin.
- Vapours can cause drowsiness and dopiness.
-> Store containers in a well-ventilated place.
-> Keep clear of ignition sources - do not smoke.
-> In the event of contact with eyes, wash thoroughly with water and consult a doctor.
-> Safety and protective measures can be found in the data sheet for acetone.
4. Rinse out the refrigerant line between the compressor and condenser using commercially available acetone, for example. The acetone dissolves the refrigerant oil ND 8 in the air-conditioning line.
A suction and pressure syringe can be used to rinse out the refrigerant line.
Suction and pressure syringe Nr.194
4.1. Allow the acetone in the refrigerant line to dry off.
WARNING
Working with compressed air
- Risk of eye injuries
- Risk of damaging and dirtying components
-> Wear protective goggles with side eye protection.
-> Protect the point at which the compressed air emerges with suitable material.
-> Place the point at which the compressed air emerges on suitable surfaces.
5. Wrap a light-coloured material several times around the refrigerant line connection for the condenser and secure the material on the line with a tie-wrap. Make sure that the compressed air can escape through the cloth. Any wear fragments must remain in the cloth.
6. Blow pure compressed air (no oil or water impurities permitted) through the refrigerant line between the compressor and condenser.
7. Replace both condensers and the desiccator. -> 875019 Removing and installing condenser Service and Repair;--> 875519 Removing and installing desiccator - section on "Removing" Service and Repair
8. Reinstall the refrigerant line between the compressor and condenser at the compressor and at the condenser. -> 874319 Removing and installing compressor-condenser line - section on "Installing" 87431903 Removing and installing compressor-condenser line in area of engine
9. Replace air conditioning compressor.
If there is no wear/chips:
10. Replace the desiccator. -> 875519 Removing and installing desiccator Service and Repair
11. Replace air conditioning compressor.
Subsequent work
1. Install drive belt. -> 137819 Removing and installing drive belt - section on "Installing" Service and Repair
2. Install oil separator. -> 10551950 Removing and installing oil separator - section on "Installing"
3. Install resonance tube. -> 247419 Removing and installing resonance tube - section on "Installing" Service and Repair
Connect the battery and carry out "Work instructions after disconnecting the battery". -> 2X00IN02 Work instructions after disconnecting the battery Work Instructions After Disconnecting the Battery.
4. Install hood compartment lid and hinges. -> 619019 Removing and installing hood compartment lid - section on "Installing" 619019 Removing and installing hood compartment lid
5. Fill refrigerant on the air-conditioning system in accordance with regulations. -> 870317 Draining and filling in refrigerant Service and Repair
6. Open air outlet nozzles on the dashboard, and set fan to at least 75 %.
7. After allowing the system to stabilise at idle speed (approx. 5 sec.), switch on air conditioner and allow the engine to run uninterrupted for at least 2 minutes at 1500 rpm.
8. Switch off the air conditioner again. Do not drive until the air conditioner has been filled.
9. Start engine. Turn the steering wheel from stop to stop while the engine is running in order to bleed the steering system.