BMW E90 N47 diesel timing chain failure
Is the timing drive a known weak point on the BMW E90 N47 diesel?
Yes, the N47 timing drive, meaning the timing chain assembly, is a known weakness. It is located at the rear of the engine and has no separate tensioner. The repair is expensive, so the fault is worth checking before buying the car.
How can you tell an N47 timing chain fault before the chain breaks?
The chain makes a faint running noise at idle, both cold and warm. As it gets worse the noise turns into grinding and whining. The noise, the engine warning light and rough running should usually appear before the chain breaks.
Is a clicking noise always from the timing chain?
No. A clicking noise can also come from the auxiliary belt tensioner pulley. Chain wear can be audible as a running noise, but it does not always mean a fault. In an unclear case, let a workshop find the source of the noise.
Does the timing drive problem affect the older M47 diesel?
No. The problem has been found in the N47 engine, not in the older M47, for example in a 2006 320d. Typical faults of the M47TU2 are the particulate filter and the intake manifold flaps, and its timing drive is more durable.