BMW 1 Series cambelt: it doesn’t have one
every 1 Series uses a timing chain — but one engine’s chain has a story you should know
- Timing chain no schedule
- N47 diesel (2007–14) known issue
- Chain job £1,200–£2,500
The BMW 1 Series has no cambelt to change — every engine uses a timing chain, which BMW treats as a lifetime part with no scheduled replacement. That’s the good news, and for most petrol models it’s the whole story. The asterisk is the N47 diesel (2007–2014, most 116d/118d/120d): its chain is a documented weak point that can stretch and fail — and because it sits at the back of the engine, the repair is one of the priciest “no maintenance needed” surprises in motoring.
1 Series timing by engine
No engine here needs routine belt money — the table shows what, if anything, to watch instead:
| Engine | Timing | What to know |
|---|---|---|
| Petrol (116i–135i, all years) | Chain | No schedule; generally robust with good oil habits |
| N47 diesel (2007–2014: most 116d/118d/120d) | Chain — rear of engine | Documented stretch/failure risk; listen for cold-start rattle |
| B47 diesel (2014 on) | Chain | Successor engine; the N47’s reputation doesn’t carry over |
Chain replacement on an N47 typically runs £1,200–£2,500 at a specialist because the engine usually has to come out to reach the rear-mounted chain.
The N47 chain — what 1 Series diesel owners should know
The symptom is a cold-start rattle from the back of the engine. A metallic rattle lasting a few seconds on a cold morning, fading as oil pressure builds, is the classic early sign of chain and guide wear — often first noticed in winter. It’s regularly misdiagnosed as injector knock; the difference is that chain rattle is worst at cold idle from the rear (windscreen side) of the engine. Most reported failures cluster from around 80,000–100,000 miles, with problems documented well before that on early builds.
Why the repair costs so much on a chain that ‘never needs changing’. BMW mounted the N47’s chain at the gearbox end of the engine — inaccessible without major dismantling, and on many cars the engine comes out. That’s why quotes run £1,200–£2,500 at specialists (dealer quotes higher), and why acting on a rattle beats waiting: a snapped chain at speed usually means valves meeting pistons and an engine beyond saving.
Buying a used 1 Series diesel: this is the check. Cold-start the car yourself — a warm engine hides the rattle. Ask about chain work history; a 2007–2014 diesel past 100k with no evidence either way prices in a £1,500+ liability. Post-2009 builds got revised chain components and fail less often, and the B47 engine from 2014 on left the problem behind. Petrol 1 Series buyers can skip this paragraph entirely.
FAQ
Does a BMW 1 Series have a cambelt or a chain?
A timing chain on every engine and every year — there is no cambelt and no scheduled replacement interval. Budget the belt money elsewhere.
Is the N47 timing chain problem still a risk?
On 2007–2014 diesels, yes — it’s an age-and-wear issue, so surviving cars are deeper into the risk window, though post-2009 revisions improved matters. The B47 engine that replaced it in 2014 doesn’t share the reputation.
What does an N47 chain replacement cost?
Typically £1,200–£2,500 at an independent BMW specialist, driven by the engine-out labour to reach the rear-mounted chain — parts are the small half of the bill. Caught at the rattle stage, the engine is usually saveable; after a snap, often not.
How do I check my 1 Series for the problem?
Cold start, bonnet up: listen for a metallic rattle from the rear of the engine that fades within seconds. Any persistent rattle, cam-correlation fault codes or metal in the oil warrants a specialist inspection before further driving.