N47/N57 Timing Chain Stretch
SeriousEngineThe 520d N47 is the major offender, but neglected N57 six-cylinder diesels can also stretch chains. Repair costs climb fast because access is poor.
Most affected: 520d, 525d, 530d, 535d
Typical symptoms
- •Rear-of-engine rattle on cold start
- •Long cranking or timing faults
- •Uneven idle once warm
What to inspect before you buy
- ✓Listen from the bellhousing side on startup
- ✓Confirm replacement with a detailed invoice
- ✓Prioritise cars with sensible oil service intervals