Assembly work involving the refrigerant system
| CAUTION | Danger of injury when working on air-conditioned vehicles! |
> Observe safety regulations for working on air-conditioned vehicles and dealing with refrigerant R134a. --> 87 AW Safety regulations for working on air-conditioned vehicles and dealing with refrigerant R134a - as of MY 2003 (All Models Except Cayenne S TIO Titan) .
> Observe safety regulations for working with extraction and filling systems. --> 80 AW SAFETY REGULATIONS FOR EXTRACTION AND FILLING SYSTEMS - AS OF MY 2003 (ALL MODELS) .
> Observe instructions for repairing air-conditioning systems and storing spare parts. --> 87 IN Instructions for repairing air-conditioning systems and storing spare parts - as of MY 2003 (All Models) .
Note. The safety regulations must be observed during all work on the refrigerant system! --> 87 AW Safety regulations for working on air-conditioned vehicles and dealing with refrigerant R134a - as of MY 2003 (All Models Except Cayenne S TIO Titan) . --> 80 AW SAFETY REGULATIONS FOR EXTRACTION AND FILLING SYSTEMS - AS OF MY 2003 (ALL MODELS) . During all work on the air-conditioning system which necessitates opening the refrigerant system, the system contents must first be disposed of correctly! Dirt and moisture must be kept out of the air-conditioning system's pipe system! Thorough cleanliness must be ensured during all work! System components must never be cleaned on the inside with hot steam! Use only nitrogen for cleaning purposes! When replacing a component, all openings must be closed off with suitable plugs!
Scheme 55
Note. Pay attention to sealing rings when disconnecting or connecting the hose connections! The charging valves are in the engine compartment, next to the feeder for the external power supply.
1. Remove the cover of the engine compartment lining.
Scheme 56
2. Unscrew the two cover nuts -arrow 1- and -arrow 2-. (Scheme 56)
1 - High pressure
2 - Low pressure
Scheme 57
Note. Before connecting the high-pressure -3- and low-pressure lines -4- to the vehicle, remove any refrigerant remaining in the lines by suction. (Scheme 57)
3. Connect the high-pressure and low-pressure lines of the air-conditioning recycling system .
3.1. Let the engine run for a short while with the air-conditioning on, then connect the high-pressure and low-pressure lines of the air-conditioning unit.
3.2. Open the valves of the high-pressure and low-pressure lines.
Note. In the case of service units with transparent oil separator, read and take note of the oil level before removing the refrigerant. Do not carry out this step with empty air-conditioning systems (pressure gauge approx. 0 bar), otherwise air will get into the refrigerant bottle. In the case of cold vehicles, it may be necessary to repeat the suction procedure until all refrigerant has been removed from the air-conditioning system. This step is carried out automatically with some units.
4. Remove refrigerant by suction.
4.1. Wait for approx. 2 minutes after the service unit has switched itself off. If the pressure gauge reading rises above 0 bar, repeat the suction process.
Note. In the case of service units with transparent oil separator, read and take note of the oil level before removing the refrigerant. Do not carry out this step with empty air-conditioning systems (pressure gauge approx. 0 bar), otherwise air will get into the refrigerant bottle. In the case of cold vehicles, it may be necessary to repeat the suction procedure until all refrigerant has been removed from the air-conditioning system. This step is carried out automatically with some units.
4.2. Drain the extracted refrigerant oil into a measuring cup on the service unit and determine the volume.
Note. The vehicle air-conditioning system is now completely empty. Necessary repairs, such as removing and fitting the dryer, can now be carried out. The open air-conditioning system should not be left open unnecessarily, but must be closed again as quickly as possible after being opened. If the air-conditioning system has been open for a long time, a new dryer must be fitted. > 875519 Removing and installing dryer
5. Carry out repairs.
5.1. If necessary, reconnect high-pressure and low-pressure lines.
6. Evacuate the system and check it for leaks.
6.1. Using the service unit, evacuate the system for 5-10 minutes.
6.2. Observe the pressure gauge for approx. 2 minutes. If the pressure rises, air is entering the vehicle air-conditioning system. The leak must be located and repaired. If the pressure remains constant, add refrigerant oil.
Note. Do not allow any air to be taken in, otherwise point 6 must be repeated.
7. Add refrigerant oil.
7.1. For units without oil filling system
7.2. Start the vacuum pump. At the start of this vacuum phase, add the measured quantity of refrigerant oil using an oil injector or a hose disconnected from the service unit. Reconnect the hose to the service unit immediately after adding the oil.
7.3. In the case of units with an integrated oil filling system
7.4. Add the measured quantity of refrigerant oil and wait for it to be taken in.
Note. If the air-conditioning system has been opened, evacuation should last at least 20 minutes so that the moisture can evaporate and be removed by suction. If the air-conditioning system has been open for a long time, evacuation can be carried out for up to 120 minutes.
8. Evacuate.
8.1. In the case of units with an integrated oil filling system, add refrigerant oil now.
| CAUTION | Low-pressure reading too high in refrigerant circuit. Destruction of air-conditioning compressor. |
> Do not allow the low-pressure gauge to exceed 3 bar, otherwise liquid refrigerant can get onto the suction side of the compressor and destroy it.
Note. As refrigerant usually flows instead of being pumped, it may not be possible - especially if the vehicle is warm and the service unit cold - to add the entire quantity. If this is the case, switch the engine and the air-conditioning on. Wait for the suction pressure to fall below 2 bar. Now open the low-pressure valve on the unit slowly and carefully until the remaining quantity has been added.
9. Fill the air-conditioning system.
9.1. Using the service unit, add the refrigerant quantity stated in the manual into the air-conditioning lines. --> 80 Technical data for air-conditioning system
Note. The refrigerant in the high-pressure and low-pressure lines is part of the filling capacity of the refrigerant in the air-conditioning system in the vehicle.
10. Add the refrigerant from both connection hoses to the air-conditioning system in the vehicle.
10.1. Close the valve on the high-pressure line and disconnect it from the vehicle.
10.2. Start the engine and air-conditioning system. When the pressure on both pressure gauges sinks below 2 bar, close the valve on the low-pressure line and disconnect it from the vehicle.
Scheme 58
Scheme 59
1. Lift cover on dashboard using plastic spatula and unclip.
2. Unplug electrical plug connection.
Scheme 60
3. Pull holder -A- apart and remove sun sensor -B-. (Scheme 60)
Scheme 61
1. Press sensor -B- into the holder until the sensor lugs engage. (Scheme 61)
Scheme 62
2. Plug in the electrical plug connection.
3. Position cover and clip into dashboard.
Disassembling heater/air-conditioning unit
Installation Location
Scheme 63
Scheme 64
1. Undo fastening screw -I- for air distributor. see scheme 206
Scheme 65
2. Unscrew fastening screws -J- for heater/air-conditioning unit housing. see scheme 207
Scheme 66
3. Pull down seal -K- over the expansion valve. (Scheme 63)
Scheme 67
4. Unscrew fastening screw -Arrow M- for heater/air-conditioning unit housing. (Scheme 65)
Scheme 68
Scheme 69
5. Lever down retaining clips with a screwdriver -L-. (Scheme 66)
Scheme 70
6. Take out the seal -N- from the housing halves. (Scheme 67)
Scheme 71
7. Unscrew the four fastening screws -3- in the area of the holding tray for the heat exchanger. (Scheme 68)
Note. There is a retaining pin on the left side underneath the heat exchanger which joins the lower holding tray (where the heat exchanger is located) to the air conditioner. As soon as the retaining pin has been pulled out, the heat exchanger with the holding tray can be folded down.
8. Raise retaining clips -6-, -7- and -8- remove the fan housing upper half. (Scheme 70), (Scheme 71), (Scheme 72).
Scheme 72
Scheme 73
Scheme 74
Scheme 75
Scheme 76
Note. Depending on the condition and reasons for replacing the evaporator, unscrew and remove the expansion valve.
9. Remove evaporator -P-. (Scheme 73)
Assembling heater/air-conditioning unit
1. Fit expansion valve. --> Tightening torque: 6.5 ftlb.
Scheme 77
2. Insert evaporator -P- into housing lower half. (Scheme 74)
Scheme 78
Note. Make sure that the seal -Q- is not damaged. If in doubt, replace. (Scheme 76)
3. Position housing upper half, press it on, making sure all three retaining clips engage.
Scheme 79
Scheme 80
Scheme 81
Scheme 82
4. Unscrew the four fastening screws -3- in area of holding tray for heat exchanger. --> Tightening torque: 1 ftlb. (Scheme 79)
Scheme 83
5. Insert seal -N- into guide of housing halves. Replace seal if in doubt. (Scheme 80)
Scheme 84
6. Connect retaining clips to housing halves and engage. Screw in fastening screws -M- for heater/air-conditioning unit housing. --> Tightening torque: 1 ftlb. (Scheme 82)
Scheme 85
Scheme 86
Scheme 87
7. Push on seal -K- over expansion valve. The seal must not show any signs of damage; replace if in doubt. (Scheme 84)
Scheme 88
8. Screw in fastening screws -J- for heater/air-conditioning unit housing. --> Tightening torque: 1 ftlb. (Scheme 85)
Scheme 89
9. Screw in fastening screw -I- for air distributor. --> Tightening torque: 1 ftlb. (Scheme 86)
Scheme 90
1. Position fan housing on the heater/air-conditioning unit housing and press on. Both retaining clips must engage -arrow-. (Scheme 87)
Scheme 91
2. Screw in the six fastening screws -2- and tighten. --> Tightening torque: 1 ftlb. (Scheme 88)
3. Position filter from below and carefully push it into the heating unit.
Scheme 92
4. Engage cover -Arrows A- and screw in fastening screws -Arrow B-. --> Tightening torque: 1 ftlb. (Scheme 89)