BMW Petrol Engines

Timing Chain Repairs

Premature timing chain failure is a serious problem for BMW owners. The issue has been featured on BBC Watchdog and is regularly discussed in BMW forums and other media sites.

Most commonly affecting the 2.0 litre diesel with the N47 engine, we also regularly rebuild damaged engines in the 3.0 litre diesel range, BMW petrol engines and also BMW Minis

A range of BMW petrol engines in cars registered between 2001 to 2015 appear to have a design problem affecting the timing chain or tensioner. The engine timing chain is very weak – it stretches over time, and ultimately snaps.

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
116i, 120i, 316i, 320i2001, 2002, 2003, 2004,
2005, 2006, 2007
N42B18 or N42B20
116i, 120i, 316i, 320i2007, 2008, 2009,
2010, 2011
N43B16 or N43B20
Model No.Year RegisteredEngine Code
125i, 220i, 225i, 228i, 320i,
328i, 420i, 428i, 520i, 528i,
X1, X3, X4, Z4
2011, 2012, 2013, 2014, 2015N20B20
118i, 120i, 318i, 320i, 520i
530i, X1, X3
2015, 2016, 2017, 2018, 2019, 2020, 2021
2022, 2023, 2024

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 timing chain has snapped then you will require the full engine rebuild procedure, which we offer from £3,000 – £6,000 + VAT inclusive of parts. Each damaged engine is individually assessed – depending on damage to engine parts, and fluctuations in BMW component pricing, the price may be higher.

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.

The History of BMW Timing Chain Failure

Early in 2013 our workshop owner was contacted by researchers from the BBC Watchdog program. The Watchdog researchers were keen to acquire real-world professional advice on this subject – 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