Compressor HVAC: Service and Repair
WM 873419 Removing and installing air-conditioning compressor
Technical values
Preliminary work
Preliminary work for removing and installing air-conditioning compressor
WARNING
Refrigerant
- Danger of freezing
-> Avoid contact with refrigerant.
-> Wear personal protective gear.
-> Observe the safety regulations for working on air-conditioned vehicles and dealing with refrigerant.
-> Observe the safety regulations for extraction and filling systems.
-> Observe the instructions for repairing air conditioning systems and storing spare parts.
1. Remove engine guard. -> 108019 Removing and installing engine guard - section on "Removing" 108019 Removing and installing engine guard
2. Drain refrigerant. -> 870317 Adding refrigerant and removing by suction Service and Repair
3. Remove drive belt. -> 137819 Removing and installing drive belt - section on "Removing" Service and Repair
Removing air-conditioning compressor
WARNING
Refrigerant
- Danger of freezing
-> Avoid contact with refrigerant.
-> Wear personal protective gear.
-> Observe the safety regulations for working on air-conditioned vehicles and dealing with refrigerant.
-> Observe the safety regulations for extraction and filling systems.
-> Observe the instructions for repairing air conditioning systems and storing spare parts.
Installation position of air-conditioning compressor
1. PDCC only:
Loosen the fastening nuts -1- used to secure the holder for the PDCC hoses and lower the holder -2- with the hoses -arrow-.
Holder for PDCC lines
2. Turbo only:
Loosen the pressure hose -1- from the charge-air cooler to the turbocharger at the screw-type clamp -2- and bend it aside.
Pressure pipe for turbo
3. Unscrew the fastening screws -1- on the air-conditioning compressor -3- at the front and lay the holder aside.
Air-conditioning compressor holder
4. Remove the refrigerant lines at the compressor.
Refrigerant lines on air-conditioning compressor
4.1. Loosen the fastening screws -1, 2- for the refrigerant lines -3, 4-.
4.2. Pull out the lines -3, 4- at the air-conditioning compressor and close off the connections with suitable stoppers.
5. Remove the line -1- from the air-conditioning compressor to the condenser -2-.
Line from air-conditioning compressor to condenser
5.1. To do this, unscrew the fastening screw -3- for the line -1- at the condenser -2-.
6. Release the plug connection -1- on the air-conditioning compressor -a- and pull it off -A-.
Plug connection for air-conditioning compressor
7. Loosen the rear fastening screw -1- on the air-conditioning compressor -2-.
Fastening screws on air-conditioning compressor
8. Make sure not to damage any parts in the engine compartment when removing the air-conditioning compressor.
Pull the air-conditioning compressor -1- forward -A- and turn the front side with the pulley to the left -B-.
Removing air-conditioning compressor - Step 1
9. Lift up the air-conditioning compressor -1- with the side of the pulley -A- and turn the rear end downwards -B-.
Removing air-conditioning compressor - Step 2
10. Pull the air-conditioning compressor -1- down and remove it from the vehicle -A-.
Removing air-conditioning compressor - Step 3
Installing air-conditioning compressor
NOTICE
Too much refrigerant oil in new air conditioning compressor.
- Risk of damage to air conditioning 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)!
Information
If a new air-conditioning compressor has to be installed, the refrigerant oil quantity in the air-conditioning compressor must be changed before installing the new air-conditioning compressor.
A new air-conditioning compressor is filled with the total amount of refrigerant oil required.
Information
- If the air conditioning compressor is blocked/seized up, then additional steps must be carried out to ensure the operation of the air conditioning. -> 873419 Removing and installing air-conditioning compressor - section on "Information"
1. Open the cap on the high-pressure side and relieve the pressure from the air-conditioning compressor -A-.
2. Open the oil filler screw -B- on the air-conditioning compressor.
Cap and oil filler screw
3. Empty approx. 60 cm3 of refrigerant oil out of the air-conditioning compressor and into a measuring glass. The remaining quantity of oil (approx. 80 cm3) remains in the air-conditioning compressor.
4. Always replace the sealing ring for the oil filler screw. => Tightening torque: 26 Nm (19 ftlb.)
5. Use fastening screws from the new air-conditioning compressor. Replace O-rings and coat the new rings with refrigerant oil.
6. First insert the air-conditioning compressor -1- with the pulley into the vehicle -A-.
Installing air-conditioning compressor - Step 1
7. Slide the air-conditioning compressor -1- as far as required in front of the engine so that it can be positioned.
Installing air-conditioning compressor - Step 2
8. Move the air-conditioning compressor -1- into installation position by turning it -A- ( -B- ).
Installing air-conditioning compressor - Step 3
9. Fit the air-conditioning compressor -1- into the holder -2-.
Installing air-conditioning compressor - Step 4
9.1. Make sure that the guides -3- on the holder fit into the bores -4- on the air-conditioning compressor.
10. Fit the rear fastening screw -1- on the air-conditioning compressor -2-.
Fastening screws for air-conditioning compressor
11. Fit the front fastening screws -1- used to secure the air-conditioning compressor -3- to the holder -2-.
Holder for air-conditioning compressor
12. Plug in electric plug connection -1- for the air-conditioning compressor -A- and lock it -a-.
Fitting electric plug connection
13. Replace the sealing rings -1, 2- on the coolant line -3- from the air-conditioning compressor to the condenser.
Sealing rings on lines
14. Fit the coolant line -1- from the air-conditioning compressor to the condenser -2-.
Line from air-conditioning compressor to condenser
14.1. Fit the coolant line -1- on the condenser -2- and screw in the fastening screw -3-.
15. Replace the sealing ring -1- on the line -2- from the air-conditioning compressor to the evaporator.
Sealing ring on coolant line
16. Position the coolant lines -1- on the air-conditioning compressor -3-.
Make sure that the guide pins -2- on the air-conditioning compressor fit into the mountings -4- for the coolant lines.
Fitting coolant lines
17. Fit the fastening screws -1, 2- for the coolant lines -3, 4-.
Refrigerant lines on air-conditioning compressor
18. Turbo only:
Connect the pressure pipe -1- from the charge-air cooler to the turbocharger on the charge-air cooler and fit the hose clamp -2-.
Pressure pipe for turbo
19. Vehicles with PDCC only:
Position the holder -2- for the PDCC lines and fit the fastening nuts -1-.
Holder for PDCC lines
Work steps for blocked/seized up air conditioning compressor
1. Remove desiccator from the condenser. -> 875519 Removing and installing desiccator - section on "Removing" Service and Repair
2. Check the desiccator for wear/chips.
If there is wear/chips:
3. Remove the refrigerant line between the compressor and condenser. -> 874319 Removing and installing compressor-condenser line - section on "Removing" 874319 Removing and installing air-conditioning compressor/condenser line
4. Replace the refrigerant line between the compressor and condenser.
5. Replace the condenser with desiccator. -> 875019 Removing and installing condenser Service and Repair
6. Install the new refrigerant line between the compressor and condenser. -> 874319 Removing and installing compressor-condenser line - section on "Installing" 874319 Removing and installing air-conditioning compressor/condenser line
7. -> 873419 Removing and installing air conditioning compressor - section on "Installing"
If there is no wear/chips:
- Replace the desiccator. -> 875519 Removing and installing desiccator Service and Repair
Subsequent work
Subsequent work for removing and installing air-conditioning compressor
1. Fit drive belt. -> 137819 Removing and installing drive belt - section on "Installing" Service and Repair
2. Fill the air-conditioning system with refrigerant. -> 870317 Adding refrigerant and removing by suction Service and Repair
3. Fit engine guard. -> 108019 Removing and installing engine guard - section on "Installing" 108019 Removing and installing engine guard
4. Open air outlet nozzles on the dashboard, and set fan to at least 75 %.
5. After allowing the system to stabilise at idle speed (approx. 5 sec.), switch on the air conditioning and allow the engine to run uninterrupted for at least 2 minutes at an engine speed of less than -> Engine speed: 1,500 rpm.
6. Switch off the air conditioning again. Do not drive until the air conditioning system has been filled.