Heating and A/C Unit, Removing and Installing
Special Tools And Equipment
- Hose Clamps, Up To 40 mm. 3093 or Hose Clamps Up To 25mm Dia. 3094
- Commercially available compressed-air gun
- Cooling system tester V.A.G 1274/ (with hand pump and appropriate adapters)
Removing
- Remove plenum chamber cover.
- Discharge refrigerant circuit Refrigerant R134a - Servicing.
- Disconnect and remove Battery A.
NOTE:
- If necessary, obtain radio anti-theft code before disconnecting Battery A.
- On vehicles with electrically adjustable seats, move seats to rearmost position before disconnecting Battery A.
- On removal, note down bolt lengths and assignment for reinstallation.
- All cable ties and other wiring harness fasteners released or cut open on removing air conditioner are to be reinstalled in same position on installation.
- Dissipate pressure in coolant circuit by opening cap at coolant reservoir.
CAUTION: On vehicles equipped with Audi Telematics by OnStar, switch-off the emergency (back-up) battery for the Telematic/Telephone Control Module prior to disconnecting the vehicle battery. Switch-on the emergency (back-up) battery after reconnecting the vehicle battery
- Mark positions of coolant hoses - A - and - B -.
- Pinch off both coolant hoses to heater core of air conditioner (e.g. using Hose Clamps Up To 25mm Dia. 3094) and remove hoses.
NOTE:
- Make sure coolant hoses are correctly connected:
- Coolant hose -A- supply from cylinder head
- Coolant hose - B - return to water pump
- Bleeding coolant circuit Engine Mechanical
- Place container beneath connection - A -.
- Install section of tubing to connection - B - and use a compressed-air gun to carefully blow the coolant out of the heater core (into the container).
- Remove grommet - C -.
- Remove refrigerant lines to evaporator and secure them (e.g. with cable tie) such that they do not impede installation.
- Remove grommet - E -.
NOTE:
- Seal open line connections.
- A cap from a replacement evaporator, for example, is suitable for sealing the open connections at the evaporator.
- Place protective covers over drivers and front passengers seats.
- Remove glove compartment, drivers storage compartment, center console and instrument panel.
NOTE: So as not to damage the instrument panel fascia, the instrument panel is only to be placed on a clean workbench covered with clean cardboard.
- Remove brace - A - for instrument panel cross member (on passengers side at transmission tunnel).
- Remove accelerator pedal module.
- Remove bolts - A - and - B - between support - C - and air conditioner.
- Remove support - C - for instrument panel cross member (on drivers side at transmission tunnel).
- Remove front footwell vent.
- Remove mounting bracket for brake pedal (and clutch pedal) from instrument panel cross member.
- Loosen hex nuts - A - for instrument panel cross member on left and screw out by approx. 15 mm.
- Remove hex nuts - B - for instrument panel cross member on right.
- Remove connecting bolts between instrument panel cross member and windshield cross member (in passenger compartment) as well as connecting bolts between instrument panel cross member and plenum chamber (between electronics box and windshield cross member in plenum chamber).
- Carefully pull instrument panel cross member to rear until it makes contact with nuts on left and is still resting on stud on right.
- Remove intermediate piece for defroster channel - A - and air guide to center instrument panel vents - B
- Remove evaporator from air conditioner.
- Remove fasteners of vehicle wiring harness (with cable ties) at air conditioner.
- Disconnect all connectors between vehicle wiring harness and electrical components at air conditioner.
NOTE: The "air conditioner" wiring harness is removed with the air conditioner.
- Remove bolts - A -.
- Take out air conditioner - A - towards passengers side.
NOTE:
- When removing air conditioner, pay attention to both coolant lines to heater core to ensure that they do not catch on opening to plenum chamber or on noise insulation mat and become bent.
- Pay attention to wiring harness. Pulling too firmly could damage individual wires.
Installing
Install in reverse order, paying attention to the following:
- Check all seals at air conditioner for damage prior to installation and replace damaged seals.
- Check attachment of coolant lines to heater core.
- Make sure coolant hoses are properly connected to heater core. observe markings:
A. Supply from cylinder head
B. Return to water pump
- Reinstall components removed (with the exception of drivers storage compartment) in reverse order.
- Bleed coolant circuit.
NOTE:
- The arrangement of the coolant lines to the heater core of the air conditioner is such that the heater core must also be bled. Proceed as follows:
- Bleed coolant circuit.
- Switch off ignition.
- Carefully open cap at coolant reservoir (observe safety precautions for opening cap).
- Loosen clamp at coolant hose - B-.
- Slide back hose - B - until hole in hose is no longer sealed off by line.
- Use cooling system tester V.A.G 1274/hand pump for example to increase pressure in coolant circuit.
- Bleed heater core by way of hose - B - until there are no bubbles in coolant emerging.
- Install coolant hose - B - and secure with clip.
- Replenish coolant if necessary.
- Check coolant circuit for leaks, paying particular attention to connection between coolant lines and heater core.
- Reinstall drivers storage compartment and remaining components removed.
- Attach refrigerant lines to evaporator.
- Check correct positioning of evaporator hose.
- Evacuate and recharge refrigerant circuit.
NOTE:
- When installing instrument panel, make sure intermediate defrost piece is properly positioned on air conditioner on insertion and that defroster vent does not squash intermediate piece on installing.
- After installing instrument panel, check exit direction and distribution of air flow from defroster vent to windshield.