BMW N47 Timing Chain

The N47 is the 2.0 litre four-cylinder diesel BMW fitted from 2007 until it was replaced by the B47 around 2014 to 2015. It went into the 116d, 118d, 120d, 316d, 318d, 320d, 520d, X1 and X3 20d, among others. Unlike most engines, the N47 has its timing chain at the back of the engine, against the gearbox, and the chain and its guides are known to wear early — particularly on cars that have gone long intervals between oil changes.

The first sign is almost always a noise: a rattle or whirring from the rear of the engine, most noticeable at idle, on a cold start or when you lift off the accelerator. Some cars show no warning lights at all until the chain snaps. When that happens the valves meet the pistons, and the repair usually becomes an engine replacement rather than a chain replacement.

Because the chain sits at the back, the engine or gearbox normally has to come out to replace it properly. That makes it a significant job, which is why we listen to the engine, check the chain stretch values and look at the service history before recommending anything. A quiet engine with a good history may only need regular oil changes and a listen at each service; a noisy one needs booking in.

When we do the job we replace the chains, guides, tensioner and sprockets as a set, along with the seals disturbed on the way in. Replacing only the part that looks worst is false economy on this engine — worn guides will eat a new chain.