Removing and installing heater coolant shut-off valve N279 (Audi S6) — AUDI

🧭 Before you start

Switch off the ignition and auxiliary heater, remove the front noise insulation and unbolt the holder carrying N279. Unplug it, clamp the coolant hoses (A, B, D, E), release the hose clamps and take the valve off. Separate valve and holder, then refit in reverse with standard clamps. Check routing of the auxiliary heater exhaust, hoses, fuel pipe and wiring, check the exhaust pipe sits through its gasket in the noise insulation, then top up and bleed the coolant.

Fits: Audi A6 C6 (4F, 2004–2011)

• Special tools named: 3094

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• Switch off the auxiliary heater as well as the ignition before starting.
• Pinch all four coolant hoses (A, B, D, E) before releasing the clamps.
• Secure the hoses with standard-type clamps as fitted originally.
• The auxiliary heater exhaust must project down through its gasket and not be obstructed.
• Top up and bleed the coolant circuit afterwards.

Written for this job from the workshop steps below · TorqFix editorial.

📋 Procedure

1. Switch off ignition (and auxiliary heater).
2. Unfasten the quick-release fasteners (1) and detach the front noise insulation.
3. Screw out the bolts (arrows).
4. Detach the holder with the heater coolant shut-off valve N279 from the studs.
5. Unplug the connector (C) at the heater coolant shut-off valve N279.

6. Pinch off the coolant hoses (A, B, D, E) with the hose clamps 3094.
7. Unfasten the hose clamps and detach the coolant hoses at the heater coolant shut-off valve N279.
8. Screw out the bolts (arrows).
9. Detach the heater coolant shut-off valve N279(B) from the holder (A).
10. Following installation, check the exhaust pipe, coolant hoses, fuel pipe and wiring to the auxiliary heater (must not make contact with other components).
11. After installing the noise insulation, check the position of the exhaust pipe (A). There must be a gasket (B) fitted between the exhaust pipe and the noise insulation. The exhaust pipe must project downwards out of the gasket and the emergence of exhaust gas from the exhaust pipe (A) must not be impeded. [Note: Secure all hose connections with standard clamps Electronic parts catalogue.]
12. Top up coolant Engine, mechanics19.
13. Bleed the coolant circuit and Engine, mechanics19.

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