Sealing upper and lower covers — AUDI

🧭 Before you start

Fits: platform code 2C0

• Renewed: upper cover

Don't miss

• Sealing surfaces must be grease-free.

🔧 Engine codes this applies to

🔩 Torque settings

Values can differ between engine variants — check the code stamped on your block.

ℹ️ Always cross-check the exact figure against your vehicle's factory manual before final tightening — a wrong torque can damage the engine. These values are extracted from workshop data and may not cover every variant or revision.

📐 57 workshop diagrams for BCA

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

📋 Procedure

1. Removing fuel tank (Autogas) .
2. Removing and installing lower cover .
3. Clamp lower cover in a holding device. [Note: Thoroughly clean O-ring grooves, bolts, blind holes and and contact surfaces using Loctite 7063.Thoroughly clean threads and blind holes with compressed air.Wear gloves and ensure items are free of grease.Bead thickness: at least 2.5 mmApplication life of silicone sealant, max 15 minutes.]
4. Thoroughly clean sealing surfaces using Loctite 7063. [Note: Sealing surfaces must be grease-free.]
5. Apply silicone adhesive sealantD 176 501 A1 to clean sealing surface (arrows) of lower cover (1).

6. Fit suitable O-ring in groove and press in evenly. Now, apply a bead of approx. 2.5 mm silicone adhesive sealantD 176 501 A1 over fitted O-ring.
7. ⚠ Apply locking fluid to threads in blind holes (down to bottom of threaded hole).Locking fluid must not be applied to threads of bolts, this can cause an air lock at the bottom of the threaded hole and the locking fluid will not harden.Do not apply locking fluid to O-ring sealing seat, otherwise the sealing capability of the O-ring is destroyed. — Squirt Loctite 242 into all 4 blind bolt holes (top arrows) and Loctite 222 into blind washer holes (bottom arrows).
8. Fit lower cover on gas tank, and tighten M6 bolts.
9. Tighten M4 washer bolts.
10. Carry out leakage test .
11. Removing and installing upper cover .
12. Clamp upper cover in a holding device. [Note: Always renew upper cover.Thoroughly clean O-ring grooves, bolts, blind holes and and contact surfaces using Loctite 7063.Thoroughly clean threads and blind holes with compressed air.Wear gloves and ensure items are free of grease.Bead thickness: at least 2.5 mmApplication life of silicone sealant, max 15 minutes.]
13. Thoroughly clean sealing surfaces using Loctite 7063.
14. Apply silicone adhesive sealantD 176 501 A1 uniformly to clean O-ring groove (arrows).
15. Fit suitable O-ring in groove and press in evenly. Now, apply a bead of approx. 2.5 mm silicone adhesive sealantD 176 501 A1 over fitted O-ring.
16. ⚠ Apply locking fluid to threads in blind holes (down to bottom of threaded hole).Locking fluid must not be applied to threads of bolts, this can cause an air lock at the bottom of the threaded hole and the locking fluid will not harden.Do not apply locking fluid to O-ring sealing seat, otherwise the sealing capability of the O-ring is destroyed. — Reinstall cover, and tighten M6 bolts.
17. Carry out a gas system test (GAP) once installation is complete 39.

Other AUDI procedures

• Checking ignition coils with final output stage – VW 1.4 BCA
• Removing and installing natural gas tanks 3 and 4
• Sealing upper and lower covers
• Removing and installing tank pressure sensor G400
• Part I: assembly overview - toothed belt drive
• Removing and installing toothed belt – Audi · 56 torque figures
• Removing engine – Audi A8 D3 · 41 torque figures
• Removing camshaft timing chain from camshafts – Audi A6/A7 C7 · 38 torque figures
• Installing engine – Audi A8 D4 · 36 torque figures
• Removing and installing camshaft timing chain · 29 torque figures