Your BMW cooling system water pump keeps coolant
in constant motion. A gear or a belt drives the
main BMW water pump. In many models, a secondary
electric water pump is installed to enhance flow
and cooling.
The water pump will not operate properly unless
the drive belt that turns it is operating correctly.
On most newer vehicles, the engine's timing
belt handles this function. On older models,
the pump and belt are external devices powered
by the main crankshaft pulley with either a
V-shaped or flat belt.
Cooling-system pumping maintenance is limited
to regular replacement of coolant and drive
belts and adjustment of belt tension (on external
systems). Pumps that are driven by the timing
belt should always be replaced when the timing
belt and tensioner are replaced.
