Engines
BMW N47 diesel timing chain: what every 320d and X3 20d owner should know
Many BMW diesels imported from Japan and the UK use the N47 engine. It is economical and strong, but the timing chain needs attention.
Which cars have the N47?
The N47 2.0-litre diesel was used from about 2007 to 2014 in cars like the E90 and F30 318d and 320d, E84 X1 18d and 20d, E83 and F25 X3 20d, F10 520d and the 1 Series 118d and 120d. From around 2014 it was replaced by the B47.
The problem
On many N47 engines, especially earlier ones, the timing chain stretches and the guides wear. The chain sits at the back of the engine against the gearbox. If it breaks, the engine is usually badly damaged.
Symptoms
- A rattle or whirring from the back of the engine, often clearer from the gearbox side.
- Noise that changes with engine speed.
- Timing-related fault codes.
How we check it
We read the full fault memory and live data with ISTA, listen with a stethoscope at the rear of the engine, and check the service history. We do not condemn an engine on a noise alone.
The repair
Because of where the chain sits, the engine normally has to come out. That is why we do this job at our workshop. The repair should include the latest-revision chain, guides, tensioner and related seals, all new OEM. While the engine is out, it is the right time to check the clutch or flywheel on manual cars and fix any oil leaks.
Other N47 checks
We also look at the DPF and EGR system, swirl flaps and injectors during a diesel diagnosis. Short city trips in Nairobi traffic are hard on diesel particulate filters.