The water pump in a car engine isn’t a complicated piece of machinery, despite its vital importance to the car’s ability to run efficiently without breaking down. Its role is to circulate water and coolant around the engine in order to keep its overall temperature, especially around the cylinder head and engine block, as low as possible when it is running. The higher the load on the engine, the more coolant will be circulated around it in order to deal with the greater levels of heat being produced.
The pump circulates coolant via centrifugal force, sending it out and drawing it in constantly via a belt attached to both the pump and the crankshaft, which keeps the pump spinning. If the engine overheats, it can break down completely and be extremely expensive to repair, which is why the pump is so important in getting the coolant to the places it needs to get to. Once it has circulated through the engine, the coolant goes to the radiator to be cooled down before returning to the pump to be circulated once more.
The water pump in your vehicle takes its power from the engine, which fuels the energy it needs to work properly. It generally operates through a belt and pulley, but there are others that operate via a gear and chain. The power that the pump generates from the engine is transferred to a shaft on which there is an impeller.
It is the impeller’s job to spin and circulate the coolant throughout your car. You can think of the impeller as being similar to that of a propeller making a boat or airplane move.
When you put the shaft and impeller together, they spin on a sealed bearing. You have to be extremely observant, because this sealed bearing is the part of the car’s water pump that does wear out.
The water pump uses centrifugal force to send fluid to the outside while it spins, causing fluid to be drawn from the center continuously. The inlet to the pump is located near the center so that fluid returning from the radiator hits the pump vanes. The pump vanes fling the fluid to the outside of the pump, where it can enter the engine.
The fluid leaving the pump flows first through the engine block and cylinder head, then into the radiator and finally back to the pump.