Removing and installing heater coolant shut-off valve: Audi A8 D4

🧭 Before you start

Fits: Audi A8 D4 (4H, 2010–2017)

• Opens: coolant

Don't miss

• Mark positions of coolant hoses (C), (D) and (E) on heater coolant shut-off valve N279(A).

📋 Procedure

1. Switch off ignition (and auxiliary heater).
2. Remove plenum chamber cover and fresh-air intake Heating, air conditioning87Air duct; Removing and installing fresh air intake and General body repairs, exterior50Bulkhead; Removing and installing plenum chamber cover.
3. ⚠ The cooling system is pressurised. When the engine is warm, the coolant temperature may be above 90 °C. Release pressure and wait for temperature to drop before performing repairs. Release the pressure in the coolant circuit by opening the cap on the coolant expansion tank 19Cooling system/coolant; Draining and filling cooling system. — Release pressure in the coolant circuit by opening the cap on the coolant expansion tank.
4. Use an absorbent cloth or absorbent paper to cover area beneath heater coolant shut-off valve N279(A).
5. Mark positions of coolant hoses (C), (D) and (E) on heater coolant shut-off valve N279(A).

6. ⚠ Ensure correct assignment of coolant hoses (C), (D) and (E) on heater coolant shut-off valve N279. If coolant hoses are interchanged, this can cause the heating in the passenger compartment to fail. — Clamp off coolant hoses (C), (D) and (E) in area of heater coolant shut-off valve N279(A) (e.g. with hose clamps up to Ø 25 mm3094).
7. Release clamps and detach coolant hoses (C), (D) and (E) from heater coolant shut-off valve N279(A).
8. Unplug electrical connector from heater coolant shut-off valve N279(A).
9. Remove bolts (F).
10. Remove heater coolant shut-off valve N279(A).
11. Butt-joint coolant hoses (C), (D) and (E) and secure with clamps.
12. Bleed coolant circuit .
13. If applicable, check activation and operation of heater coolant shut-off valve N279 in "“Guided Fault Finding”" mode.
14. Re-install remaining components (removed earlier).

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