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.
The timing chain is located in the rear end of the engine, an area that was not designed to be serviceable. Thus to fix the broken timing chain, more often than not, we would have to remove the entire engine. In a case where the timing chain snapped due to a failure of the timing chain tensioner, noticeable damage may occur to the plastic guide rails the chains are designed to ride on. These guides need plenty of fresh oil to keep it lubricated to function properly, hence this will necessitate an oil change and further inspection. Beyond replacing the chain itself, we will also replace the timing chain tensioner, and for engines with more than one tensioner, we place the whole set at once.
In certain cases, the damage to the mechanical parts in the engine may be minimal so all we may have to do will be to change the timing chain with a little servicing. However, other cases come with a massive engine damage that may require a complete overhaul of your BMW engine. Generally, considering the location of the timing chain, replacing the chain often entails the replacement/servicing of other connected mechanical components. These components usually include the tensioner, the water pump, cam seals and plastic guide rails. Timing chain replacements start at £1,200.
