BMW’s N47 engine nightmare

What is N47 engine nightmare?

Purchase a second-hand BMW 1, 3 or 5-Series built between 1st March 2007 and 1st March 2011 and don’t be too surprised if the vehicle is less reliable than you thought it would be.

Models from this era suffer from a specific problem, the N47 engine has a weakness; basically the power plant is prone to excessive timing chain wear.

Throughout 2013 and 2014 BMW owners have reported numerous cases of engine failures, many of which led to terminal decline. Rattling noises coming from the front of the engine were indicative signs that all was not well. This was closely followed by the vehicle coming to a complete standstill.

BMW N47 Engine

Timing chain problems

Previously known for their reliability, timing chain failures on BMWs have rocked the motoring industry. The N47 engine has its timing chain hidden away at the back of the unit, it’s meant to be bulletproof and this component should last the lifetime of the car.

Unfortunately this isn’t the case. Various timing chain problems have been reported by frustrated owners. The most seriously affected units that require the most extensive repairs were produced between 1st March 2009 and 5th January 2013.

Obviously BMW fitted the timing chain to the rear of the engine little expecting the fault to occur. Due to the positioning of the chain though it makes access a nightmare, the entire engine has to be removed, damaged components need to be stripped and new parts fitted as part of the engine rebuild. This is a labour intensive process and it’s costly too.

What does the timing chain do?

The timing chain links all moving parts in the car’s engine. It’s a vital engine component that needs to work flawlessly with other mechanical parts. If the timing chain fails this causes a major reaction, inlet and exhaust valves smash into the pistons, this results in catastrophic engine failure.

Models affected by this fatal flaw include:

  • 118d
  • 120d
  • 123d
  • 318d
  • 320d
  • 520d

All of these vehicles share the engine code N47/N47D20A.

Rebuilding a BMW engine that’s suffered a snapped timing chain is a complex task. If you are lucky the chain simply needs replacing, in most cases the entire engine will have to be replaced.

As you can imagine, that’s not a cheap option and by no means is this a quick fix. Prices to repair damaged engines start at £500, if a new power unit is required, this could be anywhere up to £8000.

BBC Watchdog brought this concern to light back in June 2013 and this is an ongoing problem. At the time they spoke with Principal of Forensic Engineering Associates John Dabek. He told them he was concerned there was a major manufacturing design fault with the N47 engine.

The latest update seems to indicate issues are appearing with a limited number of engines manufactured after the supposed safe date of 1st March 2011. This is worrying to say the least for owners of BMWs whose vehicles are fitted with the troublesome N47D20A.

If you are lucky, maintained your BMW service history, and used a BMW-approved garage you might be able to recoup some of the costs of a major engine overhaul. BMW has offered a few ‘goodwill gestures’ to customers that meet their strict criteria. Frustratingly, in the vast majority of cases, customers either have to pay expensive repair bills or write-off the car.

This is where we can help at Sell Your Problem Car ®. We’ll give you a free and reliable valuation for all models of BMW whether the engine is running or not. Call us on 0136 638 7967 for a fast and efficient service.