How a car’s coolant pump works
Your car’s coolant pump is a critical component as it prevents the engine from overheating. It pushes a mixture of coolant and anti-freeze via hoses through channels in the engine block and then on to the radiator, where the water is cooled by movement of air over the radiator’s fins.
As a car’s spark plugs ignite the fuel in each cylinder, a huge amount of heat is produced, so it’s the job of the cooling system, working in conjunction with the thermostat, to keep these temperatures under control.
To ensure that the engine runs at a stable, optimum temperature, the coolant/antifreeze mixture needs to be constantly propelled through the system, a process that’s dependent on the coolant pump working effectively.
Most coolant pumps are simple devices: a centrifugal pump with an impeller, contained in a metal housing. The pump is usually driven by the car’s auxiliary belt, and as the impeller turns, it forces the coolant/antifreeze out of the pump and pushes it through the engine’s cooling system. As water is forced out of the pump, more is drawn in – so the process runs continually while the engine is switched on.
You may hear these devices being called ‘water pumps’ but this is incorrect, as the car’s cooling system should be filled with the correct mixture of coolant and antifreeze.