Coolant pump
Circulates coolant through a thermal-management circuit.
On the engine or in a separate coolant loop, depending on design.
Mechanical or electric drive moves coolant; controlled pumps can vary flow independently of engine speed.
The circulation pump in a heating system.
Overheating or poor circulation can arise from pump, control, air pockets or coolant loss.
Fluids use vehicle-specific schedules. Seals, pumps and heat exchangers depend on age, condition and operating history.
Simple seals and filters can be accessible; an integrated pump, buried housing or overheating damage can make repairs more involved.
BMW uses different mechanical and electric pump arrangements across engine and electric-drive families.
BMW combustion models; additional coolant circuits also appear in hybrids and electric BMWs.