One of BMW's most common problems is the cooling system. Especially the n54 and n55 engines found in later E series and early F series Bmw's 135i/335i/535i, X3/X4/X5/X6/Z4 35i (N54, N55). The water pump in these engines is electric and operates at a variable speed map rate as required by the engine.
These water pumps are under constant high stress and as a reason do not last as long as a conventional mechanical water pump. It is also quite a job due to restricted access and it does take a bit ot time to replace. Since the thermostat is attached to the water pump, it is very good practice to replace it at the same time as the water pump because if not, when the thermostat does fail at a later stage for example, would require to do the same job again and replace coolant again. It is actually cheapeer to replace both at the same time. Depending on the age of the vehicle and condition, sometimes the coolant hoses around this are can age and also may need replacing. especially if there have been oil leaks in the past leaking onto rubber hoses which actually accelerate hose degradation.
OEM suppliers for BMW are Continental or Pierburg. We install the new water pump with brand new aluminium bolts which is a must on these engines, specified by BMW repair instructions.
