E46Forum.co.uk

Hello E46 Valvetronic owners,

This thread is for those of us with the N42 or N46 four-cylinder petrol engines found in UK models like the E46 316i and 318i (typically post-2001/facelift). While these engines can be efficient, they have a reputation for some specific issues.

Let's pool our knowledge on:

• Timing Chain & Tensioner Problems: The dreaded timing chain rattle or failure. What are the warning signs? Is preventative replacement of the chain, guides, and tensioner a good idea? Approximate costs for this job at a UK independent specialist vs. DIY?
• Valvetronic System Issues: Eccentric shaft sensor failure, Valvetronic motor problems. Symptoms (e.g., rough idle, misfires, reduced power, EML on)? Diagnosis and repair tips.
• Oil Leaks: These engines are notorious for leaks! Common culprits: vacuum pump seal, rocker cover gasket, oil filter housing gasket, sump gasket, oil pressure switch, crankshaft seals. Share your experiences and fixes.
• Misfires & Ignition Coils: Causes of misfires on the N42/N46? Reliability of ignition coils?
• Oil Consumption: Do these engines also suffer from high oil consumption like some M54s? Valve stem seals?
• CCV System: Is the CCV system as problematic as on the M54?

We're looking for:

• Your experiences with these N42/N46 engine issues in the UK.
• Recommended independent BMW specialists in the UK who are knowledgeable about N42/N46 engines.
• DIY guides or tips for tackling any of these problems.
• Reliable UK parts suppliers for N42/N46 specific components.
• Advice on what to check when buying a used E46 316i/318i with one of these engines.

If you own or have owned an E46 with an N42 or N46 engine in the UK, please share your valuable insights!

Please specify your model (316i/318i), engine (N42/N46), and year.