Heater Core: Service and Repair

Heater Core

Removing

Special tools, testers and auxiliary items required

• Drip tray for VAS6100 (VAS 6208)

• Hose clamps, up to 40 mm. (3093)

• Compressed air gun, commercially available

CAUTION!
• Switch off all electrical consumers.

• Switch ignition off and remove ignition key.

- Remove facing wall in plenum chamber.

- Place Drip tray for VAS6100 (VAS 6208) under the engine.

CAUTION!
• Scalding danger!

• The cooling system is pressurized when the engine is warm. Wear gloves and other protection and carefully release system pressure if necessary before performing repairs.

- Clamp off coolant hoses - 1 - using Hose clamps, up to 40 mm. (3093) and disconnect coolant hoses to heater core.





- Connect a section of hose - A - onto upper connection of heater core.





- Hold suitable container - B - under the lower connection - C -.

- Using a compressed air gun, carefully blow coolant from heater core into container - B -.

- Remove bolt (6 mm socket head) - 1 - from connection flange between heater core connections.





• This allows the coolant pipes to move for removing the heater core.

- Remove driver side footwell trim

- Remove left footwell air vent --> [ Left Footwell Air Vent ] Instrument Panel Vents

- Remove screws - 1 - and remove heater core trim.





- Cover floor carpet in area below heater core with leak-proof foil and absorbent paper.

- Open hose clamps - A - and disconnect coolant pipes from heater core.





- Remove heater core from heating and ventilation unit.

Installing

Install in reverse order of removal, noting the following:

- Check seals - A - and - B - installed on heater core, only install a heater core with undamaged seals.





• An incorrectly glued seal can roll up into heating and ventilation unit when sliding in the heater core.

• If seal is damaged or installed incorrectly, cold air can flow past the heater core.

- With the heater core removed, check heating and ventilation unit for soiling (via heater core opening - A -).





- If necessary remove dirt or coolant from heating and ventilation unit, for example after removing leaky heater core.

- Push heater core into the heating and ventilation unit.

- Coat sealing rings - 1 - with coolant before installing.





- Insert sealing rings - 1 - into connection on heater core.

• Ensure sealing rings are installed on the proper side, as shown in the illustration.

• If hose clamps are deformed, replace them.

- Connect coolant pipes to heater core.

- Hose clamps - A - must be able to be twisted slightly when installing onto the coolant pipes.





- Hose clamps - A - must be installed as shown in the illustration.

- Tighten hose clamps - A - to 2.0 Nm.

- Check seating of both clamps - A - after tightening screws, clamps must enclose the flange on heater core and coolant pipe completely and must not touch other components.

- Thread bolt - A - into connection flange - B - and while doing this ensure bolt is actually threaded into the mounting point intended for it.





- Check position of grommet - C - in bulkhead for proper seating.





- Seal flange for coolant pipes to heater core - A - and for expansion valve (to evaporator, only in vehicles with A/C system) - B - at grommet pass-through - C - with silicon adhesive sealant if necessary (to prevent water from penetrating).

• Sealing rings must always be replaced.

• If hose clamps are deformed, replace them.

• After replacing heater core, coolant must be replaced completely

• Check coolant circuit for leaks, pay particular attention between coolant hoses and heater core.