Faults · Timing chain
BMW timing chain noise
The engine rattles or ticks on a cold start, then goes quiet after a moment. On BMW's N47 diesels and N20 petrol engines, that can mean the timing chain or its guides are worn.
In short
The N47 diesel engine (about 2007–2015, e.g. 118d, 320d and 520d) and the N20 petrol engine (about 2011–2016, e.g. 320i, 328i and 520i) are known for wear in the timing chain and its guides. The typical symptom is a rattle or tick, often at start-up. Don't leave it: a broken timing chain can wreck the engine. BemuFIX checks the noise and gives you a fixed price for the repair up front.
Symptoms
- Rattling, ticking or whining, especially on a cold start
- The noise fades as the engine warms up, but comes back the next morning
- On the N47 diesel the noise often comes from the back of the engine, on the gearbox side
- In worse cases the engine light comes on or the engine runs unevenly
Why you shouldn't wait
A stretched chain or worn guide doesn't snap straight away, but the risk keeps growing. If the chain breaks while driving, the engine's valves and pistons can be damaged, and then the repair costs many times more.
Why the N47 repair is a big job
On the N47 the timing chain sits at the back of the engine, on the gearbox side. You can only reach it by removing the engine or the gearbox, so it takes a lot of labour. The newer B47 and B48 engines aren't known for this fault in the same way.
How we handle it at BemuFIX
- We listen to the noise and read the fault memory with a diagnostic tool (diagnostics from €49)
- We tell you whether the chain needs replacing now or can be monitored
- We give you a fixed price for the repair before any work starts
Frequently asked
Can I drive the car if the timing chain rattles?
The noise doesn't mean the chain will break right away, but the risk grows. Book an inspection soon and avoid long drives until then.
How much does a BMW timing chain replacement cost?
It depends on the engine and what else is replaced at the same time. We give you a fixed price after the inspection. Our hourly rate is €89/h.
How do I know if my car has an N47 or N20 engine?
Type your registration number to Laura at the bottom of the page or call +358 50 547 7779, and we'll check the engine for you.
Does this affect newer BMWs?
The N47 was replaced by the B47 and the N20 by the B48 around 2014–2016. Timing chain wear isn't a well-known problem on those engines.