Compressor HVAC: Service and Repair

Removing And Installing Air Conditioning Compressor

Tools







Technical values



















Preliminary work

Preliminary work on air-conditioning compressor
1. Drain refrigerant for air conditioning using an air-conditioning unit.
2. Remove air cleaner housing.
3. Remove pressure pipe.
4. Remove drive belt from generator and air-conditioning compressor.
5. Remove throttle housing.

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

Tools for air-conditioning compressor
Air-conditioning service unit.

Removing air conditioning compressor












1. Undo the fastening screws -1, 2- for the air-conditioning lines on the compressor and at the engine compartment connection point.
2. Pull the temperature sensor -3- out of the holder.







3. Unscrew the two cap nuts -4- for the fuel cooler.
4. Remove the three fastening screws -5- for the air-conditioning compressor.







5. The connection point for the electric line for the air-conditioning compressor is located behind the oil-filter console. Lift the connector out of the plastic holder and pull it apart.
6. Remove the air-conditioning compressor with the fuel cooler from the engine compartment.







7. Undo the fastening screw -6- for the fuel cooler bracket on the air-conditioning compressor and the fastening screw -7- for the air-conditioning line and remove the fuel cooler.







8. Unscrew the fastening screws -8- on the air-conditioning compressor and remove the air-conditioning lines.

Installing air conditioning compressor

1. Moisten the seals of the two refrigerant lines with refrigerant oil, slide them into the air-conditioning compressor and secure in place with the two fastening screws -8-. - Tightening torque: 23 Nm (17 ftlb.)







2. Position the fuel cooler on the air-conditioning compressor, moisten the seal of the refrigerant line with refrigerant oil and secure on the fuel cooler with the fastening screw -7-. - Tightening torque: 23 Nm (17 ftlb.)







3. Use the fastening screw -6- to secure the fuel cooler onto the air-conditioning compressor. - Tightening torque: 23 Nm (17 ftlb.)







4. Position the air-conditioning compressor with fuel cooler on the engine and use the three fastening screws -5- to secure it to the engine. - Tightening torque: 23 Nm (17 ftlb.)







5. Fit the two cap nuts -4- for the fuel cooler and tighten them.
6. Moisten the seals for the two refrigerant lines using refrigerant oil. Position the refrigerant lines on the compressor and the engine compartment connection point and secure in place with the fastening screws -1, 2-. - Tightening torque : 23 Nm (17 ftlb.)







7. Join the electric line for the air-conditioning compressor and clip it onto the bracket behind the oil-filter console.







Subsequent work

Subsequent work on air-conditioning compressor
1. Install throttle housing.
2. Fit drive belt.
3. Fit pressure pipe.
4. Install air cleaner housing.
5. Fill refrigerant on the air-conditioning system in accordance with regulations.
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.

Checking refrigerant oil in "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.