Removing and installing heater coolant shut-off valve -N279 — AUDI
Removing and installing heater coolant shut-off valve -N279 on Audi: factory workshop procedure. Full factory text, tools and checks.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📋 Procedure
Notes:
Shut-off valve is only fitted on vehicles with 8-cyl. engine as of Model Year 2002 (gradual introduction).
If voltage is not applied to shut-off valve -N279 (large coolant circuit), coolant can flow from connection -B- (from air conditioner unit heat exchanger) to connection -A- (to engine).
If voltage is applied to shut-off valve -N279 (small coolant circuit), coolant can flow from connection -B- (from air conditioner unit heat exchanger) to connection -C- (to auxiliary heater).
Connection -D- is sealed with a plug (except on Audi allroad
=>Page
82-125
).
Shut-off valve -N279 is actuated by relay -J541 in auxiliary heating mode=>Page
01-220
.
Connections -C- and -D- are interconnected in shut-off valve.
Depending on -N279 version, shut-off valve connections are marked with numbers, letters and/or arrows.
Special tools, testers and other items required
Hose clamps 3093/3094
Removing
Notes:
On removal, note down bolt lengths and assignment for re-installation.
All cable ties and other wiring harness fasteners released or cut open on removing shut-off valve are to be re-attached in same position on installation.
Switch off ignition.
Dissipate pressure in coolant circuit by opening cap at coolant expansion tank.
=> Relevant Engine, Mechanics Workshop Manual; Repair Group 19
Relevant Engine, Mechanics Workshop Manual
Remove front bumper and noise insulation (does not apply to Audi allroad).
=> General body repairs; Repair group 63; Front bumper
General body repairs
Front bumper
Unfasten power steering fluid reservoir and lay it aside or remove (Audi allroad only).
=> Running gear; Repair group 48
Running gear
Unplug connector -A- (layout on Audi allroad differs from this illustration).
Mark layout of coolant hoses -B-, -C- and -D- (layout on Audi allroad differs from this illustration).
Mark layout of coolant hoses -A-, -B-, -C- and -D- (Fig. shows layout on Audi allroad).
Pinch off coolant hoses to heater coolant shut-off valve -N279 (e.g. using V.A.G 3094) and detach hoses.
Remove bolts -E- (layout on Audi allroad differs from this illustration).
Remove shut-off valve -E- (layout on Audi allroad differs from this illustration).
Installing
Re-install components removed in reverse order.
Bleed coolant circuit =>Page
82-127
and
=> Relevant Engine, Mechanics Workshop Manual; Repair Group 19
Relevant Engine, Mechanics Workshop Manual
If necessary, check operation of shut-off valve =>Page
01-220
.
TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.