Removing and installing fuel tank with components: Audi A6 C5 (AFB, AFN, AJM, AKE, …)

🧭 Before you start

Remove interior trim and unplug the flange connectors, free the filler neck rubber cup and remove the right rear wheel and liner to undo the filler neck bolt. Remove the cover ahead of the rear axle and the levelling sender, mark and release the fuel lines including the auxiliary heater feed, support the tank on a jack and remove bolts 1 to 6. Refit with lines clipped on, the earth connection positioned and bolts 4, 5, 6 tightened before 1, 2, 3, then check earth continuity and bleed the auxiliary heater line.

Fits: Audi A6 C5 (4B)

• Opens: fuel
• Renewed: seals

Don't miss

• Empty the tank before removal; a full tank is too heavy to lower safely.
• On unit injector engines fuel can reach 100 °C; let it cool before opening the lines.
• Tighten bolts 4, 5 and 6 before bolts 1, 2 and 3.
• Check filler neck to body resistance with an ohmmeter afterwards; it should be approx. 0 Ω.
• Run the auxiliary heater at full load for 10 minutes to bleed its supply pipe.

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

🔧 Engine codes this applies to

📋 Procedure

1. Remove luggage compartment floor lining.
2. If necessary, fold forward right backrest of rear seat bench.
3. Remove left-side section of backrest (1/3 section) 72.
4. Remove left-side trim in luggage compartment and luggage compartment floor trim 70.
5. Unscrew cover for flange (arrows).

6. Unplug electrical connector (arrow) at flange.
7. Unplug electrical connectors (1) and (2) at flange.
8. Open the tank flap. [Note: Do not remove filler cap.]
9. Clean area around fuel filler neck.
10. Lever off retaining ring (arrow) in rubber cup and press rubber cup through to inside.
11. Remove rear wheel (right-side).
12. Remove rear right wheel housing liner 66.
13. Unscrew bolt (arrow) for fuel filler neck.
14. Remove cover in front of rear axle (arrows).
15. Unscrew levelling system sender for ESPG84 from body (arrows).
16. Mark fuel supply pipe and fuel return pipe (arrows).
17. ⚠ The fuel system is pressurised. Before opening the system place a clean cloth around the connection. Then release pressure by carefully loosening the connection.In extreme cases the fuel lines and the fuel can reach a temperature of 100 °C on vehicles with unit injector engine. Allow the fuel to cool down before disconnecting the lines - danger of scalding.Wear protective gloves.Wear safety goggles. — Disconnect fuel lines at connection.
18. In addition, disconnect fuel supply pipe for auxiliary heater.
19. Position engine and gearbox jackV.A.G 1383 A below vehicle to support tank.
20. ⚠ To reduce weight, fuel tank must be empty upon removal. — If necessary, mark position of securing straps for re-installation.
21. Remove bolts (1 ... 6).
22. Then lower fuel tank using engine and gearbox jackV.A.G 1383 A and turn it towards the left. [Note: The (arrow) points in direction of travel.] [Note: Secure all hose connections with the correct type of hose clips (same as original equipment) Parts catalogue.Always renew seals and gaskets when assembling.]
23. Check that fuel lines are clipped onto front right side of fuel tank (arrows).
24. Check the earth wiring at both ends for traces of oxidation. Remove any traces of oxidation if necessary.
25. Position the earth connection as illustrated (1).
26. Position the fuel tank with securing straps on underbody, using the engine and gearbox jackV.A.G 1383 A.
27. Move fuel tank all the way to the right.
28. First tighten bolts (4, 5, 6), then bolts (1, 2, 3). [Note: The (arrow) points in direction of travel.]
29. Secure the contact tab (1) of earth connection with securing bolt (2) for fuel filler neck.
30. ⚠ After installation, use an ohmmeter to check the electrical connection between the metal ring on the fuel filler neck and a bare metal part on the body:Specification: approx. 0 Ω. — Install rear right wheel housing liner 66.
31. Fit fuel lines (arrows) according to markings.
32. Plug in electrical connector.
33. After securing fuel tank mountings, press cap protecting spare wheel (1) onto end of bolt (2) in spare wheel well.
34. Let auxiliary heater run with full load for 10 minutes to bleed fuel supply pipe going to metering pump.

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