Crank/cam correlation on BMW N47 / N57 diesels — the timing chain is at the rear of the engine and notorious for stretching and snapping.
BMW P0016 — Crank/cam correlation on BMW N47 / N57 diesels — the timing chain is at the rear of the engine and notorious for stretching and snapping. Typical UK independent garage cost: £1400–£3500.
What actually causes P0016 on a BMW
BMW's N47 diesel mounted the timing chain at the rear (gearbox end) of the engine to save space — but the chain tensioner and guides wear quickly, the chain stretches, and eventually it can snap. P0016 (and often P0017/P0008) is the warning shot before catastrophic failure. The job requires the engine and gearbox to be separated — a 12–18 hour labour bill. N57 is similar but more durable. N20 petrol has its own chain-at-the-front issues that also throw P0016.
BMW engines that log P0016
- N47 2.0d (1, 3, 5 Series, X1, X3 2007–2014)
- N57 3.0d (3, 5, 7 Series, X5, X6)
- N20 2.0 petrol (later models)
How we diagnose P0016 on a BMW
- Listen for diesel chain rattle from the rear of the engine, especially on cold start and overrun
- Scan tool (ISTA or equivalent): read cam timing deviation — anything over 6° crank degrees is serious
- Check service history for previous chain work and what parts/spec was used
- If chain confirmed stretched, plan engine-out job with full BMW chain kit (genuine, not pattern)
- Replace rear main seal and inspect oil pump chain while engine is out
The common misdiagnosis to avoid
Don't let a non-BMW specialist quote 'chain only' — the guides, tensioner, sprockets and seals all need doing together, and the rear main seal usually needs replacing while you're in there. A botched N47 chain job is money down the drain.
BMW P0016 repair cost in the UK
Expect £1400–£3500 including parts and labour at an independent garage. Main-dealer quotes on BMW are usually higher for the same job, and the spread exists because the cheap cause and the expensive cause throw the same code — pay for the diagnosis before you pay for parts.
Bob's workshop tip
N47s under 80k with a full BMW service history and short oil-change intervals (8k miles, not 18k) are far less likely to fail — when buying used, walk away from anything on long-life servicing without proof of chain replacement.
Codes usually seen alongside P0016 on BMW
- P0017
- P0008
- P0335
Symptoms drivers report with P0016
- Loud metallic rattle for the first 2–4 seconds of a cold start — the classic 'death rattle'
- Long cranking before the engine catches, especially after standing overnight
- Rough lumpy idle at traffic lights, occasionally stalls
- Stop/Start stops working (ECU disables it once cam correlation drifts)
- Turbo feels lazy or flat below 2,000 RPM — timing is retarded to protect the valvetrain
- MPG drops 4–8 mpg with no other obvious cause
- Code P0011, P0014, P0017 or P0341 stored alongside P0016
Repairs that clear P0016
- Measure cam-to-crank deviation with manufacturer-aware scan tool
- Plan full timing chain kit if stretched
- Replace cam phaser if mechanically faulty
For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0016 guide.