As with any component on your car, to know when something is about to break means you have to understand where it is, what is does and what factors will affect it's operation.

The water pump on your engine is driven directly from one of the ancillary drive belts (often referred to as fan belts) this means that in an automobile with a traditional layout it will be at the front of the engine, on a front wheel drive vehicle it will be at the opposite side from the flywheel and gearbox.

In a water cooled vehicle heat is removed from the engine by a continuous flow of water, this runs through a "jacket" which surrounds the top half of the engine and is pumped to a radiator which cools the water. Without this cooling affect the engine will overheat which can ultimately cause the engine to seize.

As with any pump the fluid running through will cause much more wear if it is not clear, any debris can and will cause damage if passed through the pump. If you live in an area of hard water and do not add anything to the water first, calcified deposits can build up which can clog the pump and other parts of the engine. If the water system has not had anti-freeze or another corrosion inhibitor added the pump and waterways may start to corrode, particularly if the engine is left standing. Water pumps are not easy to service as due to their location, (the working parts are inside the engine and cannot be seen without removing) so they get no maintenance.

Although pumps can sometimes fail with no warning, there are usually signs there if you are on the look out. If the bearings in the pump are going to fail, it will not be running smoothly and this will be easiest detected as a squeak or a whine coming from that part of the engine. The water pump will also be hotter than usual to the touch. If the seals are going to fail there will be a trickle of water, and if you use antifreeze as this evaporates it leaves a useful tell tale blue streak.

Provided you drive carefully and keep an eye on the temperature gauge a water pump failure is not catastrophic. as soon as the temperature gets to hot switch the engine off. Once you have diagnosed the problem you will be able to make short drives, how far will depend on your car and the outside temperature, but you will be able to limp home. Pumps are not normally worth trying to fix. Simply replace with a new one and always flush out the cooling system at the same time, in case there is any debris left behind.

Learn more about this author, Dave Astley.
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