Compressor HVAC: Service and Repair
Removing And Installing Compressor
Tools
Technical values
Preliminary work
Preliminary work for air-conditioning compressor
1. Drain refrigerant for air-conditioning system with a refrigerant pump.
2. Remove engine compartment lid.
3. Remove rear wall cover.
4. Remove drive belt.
General warning notes
General warning notes for air-conditioning compressor
WARNING:
Safety regulations should be strictly observed when working on air-conditioned vehicles and dealing with refrigerant.
- Danger of injury.
- Safety regulations for working on air-conditioned vehicles and handling refrigerant
- Safety regulations for extraction and filling systems
- Instructions for repairing air-conditioning systems and storing spare parts
Tools and materials
Tool for air-conditioning system
Air-conditioning service unit.
Removing the air-conditioning compressor
WARNING:
Danger of injury and material damage when using Pentosin.
- Risk of skin irritation and damage to skin.
- Damage to hoses and wiring.
- Wear protective gloves and goggles.
- In the event of contact (eyes or skin), wash immediately with water.
- Collect emerging Pentosin.
- Use caps to protect the wiring against soiling and damage.
- Clean hoses and wiring immediately.
1. Remove Pentosin from the power-steering reservoir by suction and pour it into a suitable container.
2. Release bayonet lock -Arrow- on the power-steering reservoir and remove power-steering reservoir.
3. Unscrew rear Torx screw for air-conditioning compressor (M8 x 120) -1-between the pipes of the intake system.
4. Unscrew front Torx screws for air-conditioning compressor (M8 x 90) -1-and -2-.
5. Disconnect electric plug connection on the air-conditioning compressor's electric line.
6. Unclip refrigerant hoses -1-and -2-between body and intake-air distributor.
INFORMATION: After removal, place the air-conditioning compressor on a suitable protective support (e.g. foam, neoprene, etc.).
7. Guide refrigerant compressor through the rear wall opening and place on a suitable surface on the centre tunnel.
8. Unscrew both fastening screws -1, 2-, pull out the refrigerant lines carefully and close them immediately with suitable plugs.
Installing compressor
CAUTION: Risk of damaging the air-conditioning compressor.
- The engine must not be started until the air-conditioning system has been filled.
INFORMATION:
- New compressors are pressurized 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. Do not remove the plugs for the lines and compressor connection until shortly before installation.
4. Connect the lines and secure with the fastening screws -1, 2-. - Tightening torque: 20 Nm (15 ftlb.) - Tightening torque: 20 Nm (15 ftlb.)
5. Guide air-conditioning compressor through the rear wall opening and place in installation position.
6. Clip in refrigerant hoses -1-and -2-between body and intake-air distributor.
7. Clip in connector for air-conditioning compressor supply line and clip connector housing into the holder provided.
8. Screw in front Torx screws for air-conditioning compressor (M8 x 90) -1-and -2-.
9. Screw in rear Torx screw for air-conditioning compressor (M8 x 120) -1-and tighten all three screws for air-conditioning compressor. - Tightening torque: 23 Nm (17 ftlb.).
10. Position power-steering reservoir. Lock bayonet lock -Arrow-on power-steering reservoir.
11. Replace the quantity of Pentosin removed during removal with new Pentosin and pour this into the power-steering reservoir.
12. Turn the tensioning roller clockwise using a ring wrench (a/f 24), position the drive belt and then tension it.
Subsequent work
Subsequent work on compressor
1. Check Pentosin level in power-steering reservoir.
2. Install rear underbody cover.
3. Install rear wall cover.
4. Install engine compartment lid.
5. Fill refrigerant on the air-conditioning system in accordance with regulations.
6. Open air exhaust nozzles on the dashboard, and set fan to at least 75 %.
7. After allowing the system to stabilize 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.
Checking refrigerant oil in "new" air conditioning compressor
CAUTION:
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-.
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 "V(old)" 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
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. V(total) = "V(removed)" + "V(old)" + 20 cm(cubed)
2.2. V(total) = Total volume for the new air conditioning compressor
2.3. V(removed) = Volume of refrigerant oil removed by suction
2.4. V(old) = Volume of refrigerant oil in the old air conditioning compressor
2.5. 20 cm(cubed) = Additional safety volume
3. To fill the air conditioning compressor:
3.1. Fill the determined refrigerant oil volume V(total) 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.
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.
WARNING:
Acetone is a highly inflammable, irritating and combustible fluid.
- Highly inflammable.
- Irritates the eyes.
- Repeated contact can cause chapped and cracked skin.
- vapors 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-colored 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.
8. Reinstall the refrigerant line between the compressor and condenser at the compressor and at the condenser.
9. Replace air conditioning compressor.
If there is no wear/chips:
10. Replace the desiccator.
11. Replace air conditioning compressor.