Engine Overview and Common Failures
The engine number N57 is located at the junction of the block and the gearbox. Compared to the M57 diesel, the intake manifold flap system has been improved and now they can no longer detach and fall directly into the cylinders of your engine. However, they still get dirty and stuck, so the intake needs to be cleaned every 100,000 km.
Timing chain stretch: The timing chains in this engine are quite durable and only stretch after 200,000 km. However, their replacement is very difficult and expensive, as they are located on the flywheel side. It is also worth noting that sometimes there are chain breaks due to tensioner failure.
Crankshaft damper pulley: Like in many diesel engines, a crankshaft damper pulley is used here, which is quite expensive and often fails at around 100-150 thousand km. With a broken pulley, the load on the crankshaft increases and it may not withstand and crack.
Other malfunctions: The Bosch fuel system with piezo injectors is reliable, but it does not tolerate bad fuel, and the diesel particulate filter can simply clog over time, the same goes for the EGR valve. In versions where the turbocharger has a vacuum control system, the hoses often dry out.