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More servicesBMW N47 Timing Chain Rattle: Signs, Risks and What to Do
18 July 2026 · 5 min read
Which BMWs are affected?
The N47 is the 2.0 litre four-cylinder diesel BMW used from 2007 until it was replaced by the B47 around 2014 to 2015. It was fitted to the 116d, 118d, 120d, 318d, 320d, 520d, X1 and X3 20d, and it is one of the most common diesel engines on the road.
It is economical and pulls well, but its timing chain system is its best-known weakness. If you drive one of these models, it pays to know the signs.
What goes wrong
The timing chains link the crankshaft to the camshafts and keep the valves in step with the pistons. On the N47, the chains stretch and the plastic guides and tensioner wear. As they do, the chain starts to slap against the guides.
BMW placed the timing chain at the back of the engine, next to the gearbox. That makes the noise easy to mistake for a gearbox, clutch or exhaust rattle, and it also means the engine usually has to come out to replace the chain properly.
What the rattle sounds like
Owners typically describe a whirring or rattling noise from the rear of the engine. It is usually most noticeable at idle and when you lift off the accelerator, and it often gets louder once the engine is fully warm. Some cars also give a brief rattle on a cold start.
If you are not sure whether your car has it, stand at the side of the car near the windscreen with the bonnet open and the engine idling warm. A metallic whirr or rattle from that area is worth getting checked.
Why it pays to act early
If a worn chain is left, it can jump a tooth or snap. On the N47 that normally lets the pistons hit the valves, and the repair becomes a replacement engine. Replacing the chain at the rattle stage is a planned job with a known outcome.
Regular oil changes with the correct BMW oil specification help the chain last, because clean oil keeps the tensioner working properly. Long service intervals and low oil levels make wear worse.
What we do
We start by confirming the noise really is the chain rather than a heat shield, pulley or flywheel. If the chain is worn, we replace the chains, guides, tensioner and sprockets as a set, renew the seals disturbed during the job and refill with the correct oil.
We will also be honest if a very high-mileage car is not worth the investment. If you have heard a rattle, call MF Autocentre on 01922 636820 or book online. We are at 2a Stockton Close, Walsall WS2 8LH.
Buying a used N47 BMW
If you are looking at a diesel 1 Series, 3 Series or 5 Series from this era, ask whether the timing chain has already been replaced and ask to see the invoice. A car with a documented chain replacement is worth more to you than one without.
Listen to the engine warm at idle before you buy, and check the service history for regular oil changes rather than stretched intervals. We are happy to carry out a pre-purchase check on any BMW you are considering.