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Security & TechBMW N47 Timing Chain Rattle: What It Means and What to Do
By Mike, Owner, The Car Guys Bromsgrove · 12 March 2026 · 6 min read
Why the N47 has a reputation
The N47 is BMW's 2.0 litre four-cylinder diesel, built from 2007 until the B47 took over around 2014 to 2015. It is a strong, economical engine and there are thousands of them still on the road around Bromsgrove in 1 Series, 3 Series, 5 Series, X1 and X3 models. Its weak point is the timing chain.
BMW put the chain at the back of the engine, next to the gearbox. The chain and its plastic guides wear faster than they should, especially on cars that have followed long service intervals. As they wear, the chain gets slack and starts to rattle. If it breaks, the pistons hit the valves and the engine is usually finished.
What the rattle sounds like
Owners describe it as a rattle, a whirr or a metallic buzz from the back of the engine — the end nearest the windscreen. It is often loudest at idle with the bonnet open, just after a cold start, or when you lift off the accelerator at around 2,000rpm.
The tricky part is that the car usually drives perfectly well. There are rarely warning lights until something breaks. So a noise that has been there "for a while" is not a reason to relax; it is a reason to get it looked at.
If you can hear a rattle from the back of an N47 diesel, avoid long motorway runs until it has been checked. A snapped chain at speed is the worst-case outcome.
Which cars are affected
Any BMW with the N47 can be affected, including the 116d, 118d, 120d, 123d, 316d, 318d, 320d, 520d, X1 18d and 20d, and X3 20d built between 2007 and roughly 2014. BMW made revisions to the chain and guides during production, so later engines are generally better — but we still see worn chains on revised cars with poor oil change history.
Some Minis with BMW diesels also used N47-family engines. If you are not sure what is under your bonnet, give us the registration and we will check.
How we check it
We start by listening with the engine cold and then warm, because the noise changes as the oil thins. We read the fault codes and live data, look at the service history, and ask how the car is used. A car with a patchy history and a clear rattle needs a chain. A quiet car with regular oil changes may just need watching.
We do not recommend a timing chain job on guesswork. It is a big repair, and we would rather tell you your car is fine than take money for work it does not need.
What the repair involves
Because the chain is at the back, the engine or gearbox has to come out. We replace both chains, the guides, the tensioner and the sprockets together, along with the seals and gaskets disturbed on the way in. Fitting just a new chain on worn guides is false economy — the old guides quickly wear the new chain.
We finish with fresh BMW-specification oil and a road test. You get a clear quote before we start, and we show you the old parts afterwards so you can see the wear for yourself.
How to protect an N47
The best thing you can do is change the oil more often than the on-board computer suggests. We recommend roughly every 10,000 miles or once a year on these engines, with the correct BMW Longlife-approved oil. Clean oil keeps the tensioner working and slows wear on the guides.
If you have an N47 BMW and have not had the chain listened to, book it in with your next service. It takes us minutes to check and could save you an engine. Call 01527 336608 or book online.