DIY: Spark Plug Replacement

DIY: Spark Plug Replacement

The M54 uses 6 spark plugs, one per cylinder. Replace every 45,000-60,000 miles.

Parts Needed

• 6x spark plugs: Bosch FR7LPP332W (OE) or NGK BKR6EQUP
• Anti-seize compound (optional but recommended)

Procedure

1. Remove engine cover (pull up from rubber grommets)
2. Disconnect ignition coil electrical connectors (6x)
3. Remove ignition coil mounting bolts (10mm, 6x)
4. Pull ignition coils straight out
5. Use compressed air to blow debris from spark plug wells
6. Remove spark plugs with thin-wall 16mm spark plug socket
7. Check gap on new plugs (pre-gapped, verify 0.7-0.8mm)
8. Apply thin coat of anti-seize to threads
9. Hand-thread new plugs to avoid cross-threading
10. Torque to 25 Nm
11. Reinstall coils and connectors
12. Reinstall engine cover

Tips

• Inspect ignition coils while removed — replace if cracks or carbon tracking visible
• Consider replacing coils preventively if over 80k miles
• Do NOT over-torque spark plugs into aluminum head