Removing and installing bottom coolant pipe - vehicles with engine code letters AVF, AWX — AUDI

🧭 Before you start

Drain the coolant, remove the engine cover and insulation, and remove the air pipe and expansion tank. Unclip the fuel pipe brackets, detach the coolant hoses and move the wiring aside. Unbolt and pull the pipe from the block, clean the bore, fit a new O-ring lubricated with G12, push the pipe home and refill the cooling system.

Fits: Audi A6 C5 (4B)

• Opens: coolant
• Renewed: o-ring

Don't miss

• Renew the O-ring on the coolant pipe.
• Clean and smooth the sealing surface in the cylinder block.
• Lubricate the new O-ring with G12 before pushing the pipe in.
• Bleed and check the coolant level after refilling, as general practice.

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

🔧 Engine codes this applies to

📐 9 workshop diagrams for AJM

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

1. Drain off coolant .
2. Pull dipstick (1) out of guide tube.
3. Unclip cover caps.
4. Unfasten nuts (arrows) and detach engine cover.
5. Remove insulation beneath cover.

6. Re-insert dipstick in guide tube.
7. Unplug electrical connector (1).
8. Unscrew bolt (2).
9. Remove air pipe (arrows).
10. Detach coolant hoses and unfasten coolant expansion tank (arrows).
11. Unplug electrical connector for coolant shortage indicator switch F66 at expansion tank (below).
12. Unclip fuel pipe brackets (1) at bottom coolant pipe.
13. Detach coolant hoses (2) and (3).
14. Move wiring clear of bottom coolant pipe.
15. Unscrew bolts (1) and (2) and pull coolant pipe out of cylinder block (arrow). [Note: Renew O-ring.]
16. Clean and smoothen sealing surface for O-ring as required.
17. Lubricate new O-ring with “G12” and slide onto coolant pipe.
18. Push coolant pipe into bore on cylinder block.
19. Fill cooling system .

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