The central element of a coolant pump for motor vehicle engines is the impeller, also called rotor.
Depending on the type, it may have differing numbers of blades which may be straight or curved and arranged either radially or tangentially. The design and dimensions of the impeller will decisively influence the efficiency of the water pump. Further components are the driving shaft and bearing which in the case of water pumps almost always constitute one reassembled unit ready for installation. On the delivery side, the bearing shaft accommodates the impeller and on the driving side, the flange or pulley is arranged.
The pump housing is made of cast aluminum or iron. Depending on the pump type, the most diverse elements are attached to it such as holders for hoses, thermostats, plugs etc.
The pump housing is also furnished with a leak bore which serves for checking.
the shaft seal has the function to keep the transition between housing and bearing shaft tight: its functionality essentially warrants the service life of the water pump.