BMW Diesel Engine – Timing Chain Failure

Premature timing chain failure has become a serious problem for many BMW owners – regularly discussed in BMW website forums, featured on BBC Watchdog and highlighted in other media sites.

A range of BMW diesel engines produced between 2006 and 2012 appear to have a design problem affecting the timing chain. The engine timing chain is very weak – it stretches over time, and ultimately snaps.

BMW timing chains have snapped on a range of models across the 1, 3 & 5 Series, most commonly affecting the N47 diesel. We also rebuild M57 & N57 diesel engines, BMW petrol engines & also BMW Minis.

The tables below detail the affected models and engine codes:

2.0 litre Diesel BMW engines – N47
Model No. Year Registered Engine Code
118d, 120d, 123d, 318d
320d, 520d, X3
2007, 2008, 2009 N47D20A
118d, 120d, 123d, 318d
320d, 520d, X3
2009, 2010, 2011, 2012 N47D20C
3.0 litre Diesel BMW engines – M57 & N57
Model No. Year Registered Engine Code
525d, 530d, 535d, 635d, 640d, X3
X5,X6,730d, 740d
2006, 2007, 2008,2009
525d, 530d, 535d, 635d, 640d, X3
X5,X6,730d, 740d
2011, 2012 N57D30A

What Happens When A Timing Chain Snaps?

When a BMW engine timing chain snaps, the inlet and exhaust valves collide with the pistons, resulting in massive engine damage. At this point it will bend all 16 valves, shatter the rocker arms, snap and distort both camshafts and the camshaft housing.

The timing chain is located at the rear of the engine bay and is not intended to be a serviceable part.

Engine Rebuilds by “Prestige German Engines”

We have rebuilt over a thousand BMW engines damaged by timing chain failure, and we have developed a thorough, highly successful engine rebuild procedure.

Repairing the catastrophic engine damage is a labour intensive and expensive job. The timing chain is located at the rear of the engine, therefore we must remove the entire engine and completely strip down all components to discover and replace all damaged parts to ensure we restore the engine to perfect running order. The N47 or M57 engine is rebuilt with modified chains, guides and tensioners supplied by BMW to reduce the risk of a repeat failure.

If your engine has been damaged by a snapped timing chain, you will require the full engine rebuild procedure, inclusive of BMW parts.

  • Engine Code: N47D20A (2007-2009) rebuild cost will be £2,000
  • Engine Code: N47D20C (2009-2012) rebuild cost will be £3,000
  • Engine Code: M57 or N57 (2006-2012) rebuild costs vary, prices start from £3,000

Each damaged engine is individually assessed and depending on damage to engine parts, and fluctuations in BMW component pricing, the price may be higher.

Further Information on the Timing Chain Failure Issue

Early in 2013, our workshop specialist was consulted by researchers from the BBC Watchdog programme – they were keen to acquire real-world professional advice on this subject, and some of our engine rebuild customers had recommended us to BBC Watchdog as experts in this subject.

BBC Watchdog were producing a feature on the BMW timing chain failure issue, having been alerted by many unhappy BMW owners. Some of the BMW owners contacting Watchdog had been quoted huge repair costs from BMW and had instead chosen Prestige to rebuild their badly damaged engines. You can view the BBC Watchdog report on the BBC website here:

BBC Watchdog Report

Cheaper Engine Repair Options

If you are considering other companies offering so called ‘re-manufactured’ engines at under £2,000, our advice is to steer clear or do some thorough research. It is likely these engines are not rebuilt, nor re-manufactured – as genuine BMW replacement parts cost over £1,200 for the N47 and more for the M57.
It is more likely that the replacement engine will have been recovered from a damaged car – it’s also likely that it won’t have the modified BMW replacement timing chains, guides and tensioners – so they will just snap again…

It is a skilled and time consuming process to correctly repair an engine damaged by a broken timing chain, cheap solutions will not provide the reliability and 12 month warranty offered by Prestige.