Compressor HVAC: Service and Repair
Removing And Installing The Compressor
Removing the compressor
1. Remove the cover above the heating/air-conditioning system.
2. Remove the refrigerant by suction using the service unit.
3. Disconnect the battery and cover terminal or battery. Remove the complete air cleaner assembly. Undo the fastening screw for the air cleaner housing and the hose clamp on the air flow sensor.
4. Undo the hose on the charge air cooler at the left and right on the pressure pipe.
5. Disconnect the electrical plug connection on the air flow sensor and remove the complete air cleaner assembly.
6. Remove the pressure pipe to the throttle body and disengage frequency valve on the holder.
7. Just loosen belt pulley for hydraulic pump. Relieve the drive belt at the tensioning pulley and remove the belt.
8. Remove belt pulley for hydraulic pump.
9. Undo fastening screws on the expansion tank (2 M8 screws) and the hydraulic pump (3 M8 screws and one M6). Leave aside expansion tank with hydraulic pump and connected lines.
10. Undo the fuel supply lines on the fuel cooler. Make sure to counter when doing this.
11. Remove throttle body.
12. Disconnect electrical plug connection for compressor.
13. Undo the compressor from the console (3 screws).
14. Lift the compressor with fastening screws out of the bracket and carefully remove to the rear.
NOTE: The hydraulic pump with expansion tank must be lifted slightly upwards when doing this.
15. Undo the refrigerant lines at the compressor. Immediately close connections and lines with plugs so that they are air-tight.
Installing the compressor
NOTE:
- 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. 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. Empty approx. 80 cb.cm of refrigerant oil out of the compressor and into a measuring glass. The remaining quantity of oil (approx. 120 cb.cm ) remains in the compressor.
4. Always replace the sealing ring.
Tightening torque for oil filler plug M10 x 1: 26 to 36 Nm (19 to 27 ftlb.)
5. Use fastening screws from the new compressor. Replace O-rings and wet the new rings with refrigerant oil.
Tightening torque for refrigerant line, screws M8 x 32: 23 Nm (17 ftlb.)
6. Do not remove the plugs for the lines and compressor connection until shortly before installation.
7. Install compressor with lines.
8. Engage electrical connection and install compressor with fastening screws.
9. Install expansion tank with hydraulic pump.
Tightening torque for the compressor fastening screws on the console, M8 screws: 23 Nm (17 ftlb.)
Tightening torques of the fastening screws for the belt pulley and hydraulic pump expansion tank: M8 screws: 23 Nm (17 ftlb.) M6 screw: 10 Nm (7.5 ftlb.)
10. Mount belt pulley for hydraulic pump and fit drive belt.
11. Install throttle body and engage frequency valve.
12. Fasten the fuel supply lines on the fuel cooler. Make sure to counter when doing this.
13. Install the pressure pipe to the throttle body and air cleaner assembly.
14. Secure the hose on the left and right on the pressure pipe.
15. Connect the battery.
16. Fill the heating/air-conditioning system with refrigerant.
Running-in regulations for new compressor
NOTE: Fill the air-conditioning system (fluid) via the high-pressure side from the refrigerant circuit with the engine OFF.
1. If possible, all air outlet nozzles OPEN, circulating air CLOSED.
2. Start the engine and allow idle speed to stabilise (approx. 5 seconds).
3. Set the fan to max. output.
4. Switch on the air-conditioning system AC switch and allow it to run uninterrupted for at least 2 minutes at 1500 rpm.
5. After 2 minutes uninterrupted compressor operation time, the oil distribution in the air-conditioning system is completed and the compressor can be run up to the max. engine speed.