The liquid cooling medium used at that time was pure water, mixed with a small amount of wood alcohol at most to prevent freezing.The circulation of cooling water is completely dependent on the natural phenomenon of heat convection.After the cooling water absorbs heat from the cylinder, it naturally flows upward and enters the upper part of the radiator.After cooling, the cooling water naturally sinks to the bottom of the radiator and enters the lower part of the cylinder.Using this thermosiphon principle, the cooling task is almost impossible.But soon after, pumps were added to the cooling system to make the cooling water flow faster.

Centrifugal pumps are generally used in the cooling system of modern automobile engines.The most logical location for the pump is at the bottom of the cooling system, but most pumps are located in the middle of the cooling system and a few are located on top of the engine.The water pump installed at the top of the engine is prone to cavitation.No matter where the pump is, the amount of water is very large.For example, a water pump in a V8 engine will produce about 750L/h of water at idle and about 12,000 L/h at high speed.

In terms of service life, the biggest change in the pump design was the appearance of the ceramic seal a few years ago.Compared to the rubber or leather seals previously used, ceramic seals are more wear-resistant, but are also prone to scratches by hard particles in the cooling water.Although in order to prevent pump seal failure and continuous design improvements, but so far there is no guarantee that the pump seal is not a problem.Once there is a leak in the seal, the lubrication of the pump bearing will be washed away.