BMW N47 Timing Chain — The Used Buyer's Guide
The N47 timing chain is the single most searched BMW reliability concern on the UK used market. This is the buyer-focused answer: what goes wrong, who it affects, what it costs to fix, and how to price the risk into a used purchase.
Quick answer
The BMW N47 timing chain can stretch or snap, typically between 60,000 and 120,000 miles. On pre-2011 builds the chain is at the rear of the engine (gearbox-out job, £1,500–£2,500 at a specialist). Chain failure usually destroys the engine — a £4,000–£6,000 rebuild bill. Before buying any N47 BMW: listen on a cold start, ask for chain-replacement paperwork, and verify the build date. Without evidence, treat the car as a £1,500–£2,500 liability and negotiate accordingly.
What causes the N47 timing chain problem?
The N47's timing chain runs between the crankshaft and camshafts, keeping the valves in sync with the pistons. On this engine, the chain stretches over time — more than on other BMW diesels and well beyond what BMW's service schedule accounts for. Stretched chain means misaligned valve timing; in mild cases you'll see rough running and fault codes, in worst cases the chain snaps and the valves meet the pistons at full rpm.
Contributing factors: extended oil-change intervals (BMW's 18,000-mile "lifetime" fill is universally rejected by independent specialists as too long for this engine), chain design weakness, and — on pre-2011 builds — a rear-mounted chain that makes inspection and preventative replacement prohibitively expensive.
Symptoms — what to listen for
- Diesel-rattle on cold start that lasts more than a couple of seconds and fades as the engine warms. This is the single most reliable symptom. Record it on your phone during a viewing.
- Whirring or grinding from the rear of the engine (pre-2011 rear-chain builds) — listen under the bonnet with the engine idling.
- Fault codes P0016, P0017, or P0018 — cam-crank correlation errors. A £20 OBD2 reader will pull these.
- "Engine warning light" that comes back on after being reset.
- Rough idle, especially when cold.
- Reduced power / limp mode.
Any one of these, in isolation, warrants a specialist assessment before purchase. Two or more: walk away unless the seller drops the price by the full chain-replacement cost.
Affected BMW models
The N47 was fitted across most BMW four-cylinder diesels from 2007 to 2014. The full list:
| Series | Chassis code | Badge | Years |
|---|---|---|---|
| 1 Series | E81/E82/E87/E88 | 116d, 118d, 120d, 123d | 2007–2012 |
| 1 Series | F20/F21 | 116d, 118d, 120d, 125d | 2011–2014 |
| 3 Series | E90/E91/E92/E93 | 316d, 318d, 320d, 325d | 2007–2012 |
| 3 Series | F30/F31 | 316d, 318d, 320d | 2012–2014 |
| 4 Series | F32/F33/F36 | 420d, 425d | 2013–2014 |
| 5 Series | F10/F11 | 520d, 525d | 2010–2014 |
| X1 | E84 | 18d, 20d, 23d | 2009–2014 |
| X3 | F25 | 18d, 20d | 2011–2014 |
| X4 | F26 | 20d | 2014 |
From 2014 onwards the N47 was replaced by the B47, which resolved most of the timing-chain concern. See the B47 reliability guide.
UK repair-cost exposure
| Scenario | Typical UK cost |
|---|---|
| Preventative chain replacement, front-chain (post-2011) build, independent BMW specialist | £1,500–£2,000 |
| Preventative chain replacement, rear-chain (pre-2011) build — gearbox out | £2,000–£2,500 |
| Same job at a BMW main dealer | £3,000–£4,000 |
| Reactive replacement after chain snap — rebuilt/used engine | £4,000–£6,000 |
| Reactive replacement after chain snap — full BMW-main-dealer engine | £6,000–£10,000 |
Typical indie specialists for this job: SpecialistBMW (national), Munich Legends, Marshall BMW independents. Always ask for a written quote that itemises tensioner, guides, and related gaskets — the cheap quotes often skip parts that should be replaced at the same time.
What evidence should a buyer ask for?
- Chain replacement invoice with parts list (chain, tensioner, guides, oil-pump chain where applicable).
- Mileage at replacement — is it recent enough that the new chain has plenty of life?
- Workshop identity — BMW main dealer, well-known indie specialist, or unknown garage? The quality matters.
- Oil-change history — service every 7,500–10,000 miles is the independent-specialist consensus, far shorter than BMW's 18,000-mile fill.
- Full service history that doesn't skip the preventative window (60,000–80,000 miles).
- MOT history — failed emissions or chain-related advisories are visible in the gov.uk MOT data.
Buy, negotiate, or walk away
Buy
Documented chain replacement within the last 30,000 miles at a known BMW specialist, parts itemised on the invoice, no cold-start rattle, fault-code scan clean, full service history.
Negotiate
No chain paperwork but 60,000–100,000 miles with clean history, no rattle, no codes. Offer the current market price minus the £1,500–£2,500 preventative chain bill. If the seller reasons you're not being fair, point them at this page.
Walk away
Any cold-start rattle that lasts more than a couple of seconds. Pre-2011 rear-chain build with no history and 120k+ miles. Seller evasive about service or produces no paperwork. Visible oil contamination that suggests the chain timing has already slipped.
This page is for general buyer information. It does not replace a physical inspection by a qualified BMW specialist or an independent workshop-level assessment of chain wear. Cost ranges are indicative UK figures that vary by region, workshop, and parts supply — always get a written quote.
Found an N47 listing you're considering?
Paste the listing or VIN into Bimmer.AI — we'll flag the exact build date, whether the EGR recall applies, and fold the timing-chain risk into the buyer verdict.
Run a Bimmer.AI buyer report →Frequently asked questions
Is the N47 timing chain guaranteed to fail?
No. Many N47s run past 200,000 miles without chain failure when the oil is changed every 7,500–10,000 miles and short-journey abuse is avoided. But the failure rate is significantly higher than other BMW diesels and high enough that every buyer needs to price the risk explicitly.
How much does N47 timing-chain replacement cost in the UK?
£1,500–£2,500 at a BMW specialist, including new tensioner, guides, and related gaskets. Pre-2011 rear-chain builds sit at the top of that range (gearbox-out labour). Post-2011 front-chain builds are cheaper to access. Get two quotes — prices vary significantly by region.
What are the early warning signs?
A diesel-rattle on a cold start that lasts more than a couple of seconds and fades as the engine warms, a whirring or grinding noise from the rear of the engine (on pre-2011 builds), or cam-crank correlation fault codes (P0016, P0017) on a diagnostic scan. Any of these warrants an immediate specialist assessment — do not drive the car hard.
At what mileage should I worry?
60,000 miles is when the highest-severity failures start appearing in the DVSA MOT history data. 80,000–120,000 is the danger zone. Past 120,000 miles without documented chain work, treat the car as a £1,500–£2,500 liability and price accordingly.
Is the chain at the front or rear of the engine?
Pre-2011 N47 builds: rear (gearbox-out job, highest labour cost). Post-2011: front (still specialist but significantly cheaper). Verify the build date — this alone changes the repair-cost exposure by £500–£1,000.
Should I buy an N47 with the chain already replaced?
Yes, with paperwork. A documented chain replacement with parts receipts from a known BMW specialist is a real positive — it's effectively 'the expensive thing already done'. Ask for the invoice and the mileage it was done at; you want to see the tensioner, guides, and ideally the oil-pump chain were all replaced at the same time.
Is there a BMW recall on the N47 timing chain?
No formal recall in the UK. BMW has declined goodwill on almost all out-of-warranty cases. There has been sustained class-action discussion but no regulator action. The EGR-cooler fire-risk recall (NSC R/2018/151) covers a different system entirely.
What about the B47 that replaced the N47 — does it have the same problem?
Early B47 (2014–2016) saw occasional chain stretch, but post-2017 builds are rarely affected. The timing-chain fear is largely an N47 story. If ULEZ compliance matters and chain risk worries you, the B47 is the safer choice.