BMW Diesel Engines


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 2015 appear to have a design problem affecting the timing chain. The timing chain is located at the rear of the engine bay and is not intended to be a serviceable part. It 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.

From 2015 to the present, the B47 diesel engine also suffers with an inherent ‘bottom-end’ failure. This is due to the valve cover breather blocking which causes the turbo to fail and consequently the engine runs dry of oil.

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. This damage can include blown pistons, bent valves, shattered rocker arms, snapped or bent camshaft, snapped or bent crankshaft & damaged camshaft housing.

The tables below detail the affected models and engine codes:

Model No.Year RegisteredEngine Code
118d, 120d, 123d, 318d
320d, 520d, X3
2007, 2008, 2009N47D20A
118d, 120d, 123d, 318d
320d, 520d, X3
2009, 2010, 2011, 2012, 2013, 2014, 2015N47D20C
118d, 120d, 318d, 320d, 520d
X1, X3
2015, 2016, 2017, 2018, 2019, 2020, 2021
2022, 2023, 2024
Model No.Year RegisteredEngine Code
525d, 530d, 535d, 635d, 640d, X3
X5,X6,730d, 740d
2006, 2007, 2008,2009, 2010M57306D1
525d, 530d, 535d, 635d, 640d, X3
X5,X6,730d, 740d
2011, 2012, 2013, 2014, 2015, 2016
2017, 2018, 2019

BMW Engine Rebuild Service

We have rebuilt over two thousand damaged BMW engines. Typically damaged by timing chain failure but also by water ingress, oil starvation, swirl-flap failure and various other causes. We have developed a thorough, highly successful engine rebuild procedure.

Identifying & repairing the catastrophic engine damage is a labour intensive and expensive job. The timing chain is located at the rear of the engine bay. 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.

We only perform full factory specification rebuilds using genuine OEM parts. The engine is rebuilt with modified chains, guides and tensioners supplied by BMW, to minimise the risk of a repeat failure.

Engine Rebuild Costs

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 between £2,000 – £3,000 + VAT
  • Engine Code: N47D20C (2009-2015) rebuild cost will be between £3,000 – £4,000 + VAT
  • Engine Code: M57 or N57 (2006-2015) rebuild costs vary, prices start from £6,000 – £8,000 + VAT

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.