Timing Chain Repair

What is a timing chain

One of the most common engine failures is a stretched or jumped timing chain. A timing chain connects the camshaft and crankshaft. The timing chain ensures that inlet and outlet valves always open and close on time.  Modern engines are lightweight. Therefore, every component is as sturdy as necessary. Single row chains reduce the weight of engines. However, they are more susceptible to stretching forces. This results in a few problems – a stretched, jumped or broken chain and consequently engine failure.

BMW M3 timing chain
BMW M3 engine. Timing chain is marked red.

Affected engines

    1.  All four cylinder petrol and diesel engines from 07/2002 to now.
    2. All six cylinder petrol and diesel (2.5l, 3.0l, 3.5l) 07/2006 to now and eight cylinder engines (4.7l, 5.5l) from 07/2004 to 2019.
    1. All diesel engines with engine code N47.
    2. All petrol engines with engine code N20 and B20.
  3. VW and Audi Group (VAG)
    1. All petrol and diesel engines with timing chain fitted.

Stretched timing chain

A stretched timing chain usually starts to make hardly noticeable noises in the engine bay. With time, a timing chain gets longer and the noise will increase. Dependent on make and model you will hear these noises even inside the car. In this case we strongly recommend turning off the engine in order to avoid very expensive engine repairs. In the worst case a timing chain can jump or even break. Dependent on engine and service history, a timing chain should be replaced every 50K to 150K kilometres. The usage of non-manufacturer approved engine oils and oil filters can reduce the life-span of the timing parts.  In some cases gearwheels are worn and must be replaced as well. 

Stretched timing chain (Mercedes-Benz M271 engine)
Stretched timing chain and damaged gearwheel (Mercedes-Benz M271 engine).

Jumped timing chain

A stretched timing chain can even increase the wear of gearwheels. As a result of worn gearwheels, timing chain can jump which will lead to damages on pistons, piston rods and valves, as well as engine block and timing cover (see picture). Red areas mark the damaged parts.

Jumped timing chain
Damage on engine block as a result of jumped timing chain
Damaged front cover
Timing cover damaged by a broken timing chain (BMW 4 cylinder diesel engine). A blue spot marks a hole in the front cover.

How can Autohaus Dietler assist you?

Should we detect any noticeable engine noises during a scheduled service, we will contact you immediately to discuss further steps. 

  1. Diagnostic
    1.  Check basic position of camshaft and crankshaft using special timing adjustment tools.
    2. Visual check for stretched chain, worn gearwheels and damaged chain gliders.
  2. Prepare a repair cost estimate
  3. Book a repair appointment and order the parts
    1. Dependent on urgency, we will suggest appointment slots to you.
    2. We will order all parts that need to be replaced (genuine or OEM), as we do not recommend using third party parts.
    3. We will perform the repairs strictly according to manufacturer’s specifications.
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