Heater Core

Heater Core

Special tools, testers and auxiliary items required

• Hose Clamps Up To Diameter 25 mm (3094)

• Cooling System Tester (V.A.G 1274) (hand pump and corresponding adapter)

Removing

- Switch off ignition.

- Release pressure in cooling circuit by opening cap on coolant expansion tank.

- Bring rear heating & A/C unit into service position, refer to => [ Rear Heating & A/C Unit, Bringing Into Service Position ] Rear Heating & A/C Unit, Bringing Into Service Position.

- Remove Left Rear Air Door Motor (V239) => [ Left Rear Air Door Motor (V239) ] Left Rear Air Door Motor (V239).

- Remove Right Rear Air Door Motor (V240) => [ Right Rear Air Door Motor ] Right Rear Air Door Motor (V240).

- Remove bolts - A - and remove upper cover - B -.






- Mark both coolant hoses - A - and - B - to rear heater core - C - (risk of interchange).






- Clamp off both coolant hoses - A - and - B - to rear heater core - C - (for example, using (3094) ).

- Pull heater core - C - out of heating & A/C unit.

- Cover the area below heating & A/C unit, where any coolant flowing out may reach, with absorbent paper (so that any coolant flowing out will not flow on and into heating & A/C unit or on to floor mat).

- Place a container under both connections to heater core - C - and disconnect both coolant hoses.

Installing

- Clean rear heating & A/C unit (for example, of coolant residue).

- Check foam seals at heater core - A -, they must be glued on without gaps and must not be damaged.






- Insert heater core - C - into heating & A/C unit.






- Connect coolant hose - B - to coolant pipe to heater core - C - (coolant hose - A - is not connected for the time being).

• Connect coolant hoses on proper side, coolant hose - B - supply from engine (via pipe group under left fender) and coolant hose - A - return to engine (via pipe group under left fender), refer to => [ Incorporation of Front HVAC System into Cooling Circuit ] Incorporation of Front HVAC System Into Cooling Circuit.

- Fill coolant into coolant expansion tank up to top marking.

- Cover the area below heating & A/C unit, where any coolant flowing out may reach, with absorbent paper (so that any coolant still present will not flow on and into heating & A/C unit or on to floor mat).

- Place a container under connection - A - to heater core - C -.

- Open (3094) on coolant hose - B - far enough that coolant can flow slowly into heater core (to pre-bleed heater core).

• If coolant does not flow into heater core on its own, pressure can be built up in coolant expansion tank using hand pump of (V.A.G 1274) and thereby accelerate the flow.

• By pre-bleeding the cooling circuit, bleeding of the cooling system after installation is greatly simplified on first starting in operation, refer to => [ Coolant System, Bleeding ] Coolant System, Bleeding.

- Wait until coolant exits from coolant hose connection - A - on coolant pipe to heater core.

- Connect coolant hose - A - at coolant pipe to heater core.

- Install the removed components again in reverse order.

- Bleed cooling circuit. Refer to => [ Coolant System, Bleeding ] Coolant System, Bleeding.