Compressor HVAC: Service and Repair

Removing And Installing Compressor

Tools







Technical values







Preliminary work
1. Remove air cleaner housing.
2. Remove resonance tube.
3. Release drive belt.
4. Drain refrigerant for air conditioning with an air-conditioning unit.

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.

Tools and materials

Tools for air-conditioning compressor
Air-conditioning service unit, refer to Special Tools, Commercially Available Tools, Chapter 2.4, No. 96-2)

Removing compressor







1. Unscrew fastening screw on crankcase vent line -1- at the oil filter and pull out crankcase vent line -3-.







2. Unclip crankcase vent line -2- and fold it to the left.







3. Remove and unplug electric connector -4- from the top bracket on the compressor.







4. Unscrew the three fastening screws on the compressor -5- and remove the bracket -6-.







5. Place compressor along with the lines on the rear carrier plate and unscrew the two fastening screws -7, 8-.
6. Immediately close off connections and lines using suitable stoppers.

Installing 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, correct the refrigerant oil quantity in the compressor first.
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 screw in the two fastening screws -7, 8-.
- Tightening torque: 23 Nm (17 ftlb.)
- Tightening torque: 23 Nm (17 ftlb.)







5. Fit compressor and bracket -6- and screw in the three fastening screws -5-.
- Tightening torque: 23 Nm (17 ftlb.)







6. Plug in electric connector until the connector engages securely and slides onto the top bracket on the compressor.
7. Replace seals on the crankcase vent line.







8. Fold crankcase vent line to the right and clip it in -2-.







9. Fit crankcase vent line on the oil filter and screw in fastening screw -1-.
- Tightening torque: 10 Nm (7.5 ftlb.)

Subsequent work
1. Secure the drive belt.
2. Install resonance tube.
3. Install air cleaner housing.
4. Fill refrigerant on the air-conditioning system in accordance with regulations.
5. Open air outlet nozzles on the dashboard, and set fan to at least 75 %.
6. 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.
7. Switch off the air conditioner again. Do not drive until the air conditioner has been filled.

Checking refrigerant oil in "new" air conditioning compressor

Correct the refrigerant oil level in the "new" air conditioning compressor

NOTE:
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 cm3
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 cm3 = 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.
- 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.
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.