BMW Timing Chain Failure


The N47 Timing Chain Problem
Premature timing chain failure has become a serious problem for some BMW owners – regularly discussed in BMW website forums, featured on BBC Watchdog and highlighted in other media sites.

The BMW diesel engine N47D20A (aka N47) produced from March 2007 to March 2011 appears to have a design problem affecting the timing chain. The timing chains are very weak and stretch over time, causing them to snap.

BMW timing chains have snapped on a range of models across the 1 Series, 3 Series and 5 Series.

The specific BMW models with engine code : N47 / N47D20A are detailed in the table below.

BMW Models Years
Engine Codes
118d 2007,2008,2009,2010,2011 N47 / N47D20A
120d 2007,2008,2009,2010,2011 N47 / N47D20A
123d 2007,2008,2009,2010,2011 N47 / N47D20A
318d 2007,2008,2009,2010,2011 N47 / N47D20A
320d 2007,2008,2009,2010,2011 N47 / N47D20A
520d 2007,2008,2009,2010,2011 N47 / N47D20A

The timing chain is located at the rear of the engine bay and is not intended to be a serviceable part, as described here by John Dabek, Principal of Forensic Engineering Associates.

IAAF e-Bulletin – BMW attempt to deflect blame for engine timing chain failure

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.

Engine Rebuilds by “Prestige German Engines”
We have rebuilt several hundred BMW engines damaged by timing chain failure, and 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 engine is rebuilt with modified chains, guides and tensioners supplied by BMW to reduce the risk of a repeat failure.

If your timing chain has snapped then you will require the full engine rebuild procedure, which we offer from £2,500 inclusive of parts.
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 their report on the BBC website here:

BBC Watchdog Report – BMW Timing Chain Failure – N47

About Prestige Engine Rebuild & Repair Services
We are BMW diesel engine rebuild specialists and we became aware of the broken timing chain problem several years ago.

Combined with the ‘Swirl Flap failure’ problem, we have rebuilt over 250 engines in the last few years including the 118d, 120d, 123d, 318d, 320d, 520d.

I have personally been working on German cars for the past 25 years and I am also a fully qualified Mercedes Benz trained technician and engine assembler.

The team at Prestige have a well deserved reputation for technical excellence and superb customer care. We will collect your car from anywhere within mainland UK, rebuild the engine, replacing all damaged parts and you will be able to enjoy driving it once again.

If you need any advice or help, please call Steve Baker at Prestige German Automotive on 07792 300252 to discuss your individual engine repair requirements and I will quote your engine repair work. Many thanks for taking the time to read.

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. The chances are, the engines are not rebuilt, nor re-manufactured, as genuine BMW replacement parts cost over £1,200.
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 are unlikely to provide the reliability and warranty offered by Prestige.