Removing and installing rear coolant pipe: Audi A8 D2 (ACK, AKF, ALG, AMX, …)

🧭 Before you start

Drain the coolant and remove the intake manifold. Clear the crankcase breather hose, the coolant temperature sender connector, the secondary air connecting pipe and combination valve with their vacuum hoses, and the coolant and heater hoses, then free the wiring and take out the 2 bolts holding the pipe. Clean the O-ring sealing surfaces, fit new gaskets and O-rings moistened with G12+, refit the manifold and refill the coolant.

Fits: Audi A8 D2 (4D)

• Renewed: gaskets

Don't miss

• Renew all gaskets and O-rings on the pipe and secondary air parts.
• Clean and smooth the O-ring sealing surfaces before fitting the pipe.
• Moisten new O-rings with G12+ coolant, not grease.
• Use standard hose clamps and refit cable ties in their original positions.
• Check the cooling system for leaks once warm and topped up; air trapped at the rear can mislead the level.

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

🔧 Engine codes this applies to

📋 Procedure

1. Drain off coolant at engine .
2. Remove intake manifold .
3. Remove crankcase breather hose (arrows).
4. Unplug connector at coolant temperature gauge sender G2/coolant temperature sender G62.
5. Disconnect hose (arrow) from secondary air connecting pipe.

6. Disconnect vacuum hose (4) at secondary air combination valve.
7. Screw out bolts (3).
8. Screw out bolt (1) for connecting pipe holder.
9. Screw out bolt at front right connecting pipe.
10. Screw out coolant pipe bolts (2).
11. Detach coolant hose (3).
12. Detach coolant hose to heating system heat exchanger at rear coolant pipe.
13. Disconnect vacuum hose (1) at secondary air combination valve.
14. Screw out connection (4).
15. Screw out bolt (5).
16. Screw out bolts (2) and detach secondary air connecting pipe.
17. Screw out bolts (7) and detach secondary air combination valve.
18. Lay bare wires at rear coolant pipe.
19. Screw out the 2 bolts (6) at the rear coolant pipe and detach coolant pipe. [Note: Replace gaskets and O-rings.Secure all hose connections with standard clamps Parts catalogue.Re-attach all cable ties in the same locations on installation.]
20. Before installing, clean/smooth sealing surface for O-rings.
21. Moisten new O-ring with “G12+” and slip onto coolant pipe.
22. Install intake manifold .
23. Replenish coolant .

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