Cooling systems keep engines from overheating, and if one part of the system breaks down you can wind up with a car that won't run. Nearly every car and truck, with the exception of older models and a handful of new ones, uses a liquid-cooling system that pumps coolant through pipes that run through the engine.

As the liquid passes through the hot engine, it absorbs the heat, which is then dispelled through the radiator. In order to propel the fluids, the engine relies on the water pump to push the coolant through the system, and if this auto part is not functioning properly, the engine can lose its cool pretty quickly. An overheated engine can lead to a blown head gasket, overhead cam damage and boiling coolant. If the pump can't move the fluids, the engine will grow hotter and the coolant will as well. Overheated coolant can cause hoses to burst and damage the radiator. In some cases, coolant can potentially leak into the engine and destroy it.

If you notice that the engine temperature has been higher than usual, odds are that there could be a problem in the cooling system. The first thing you can do is check the coolant fluid levels and inspect the hoses for any signs of visible damage. If you find no indications of problems with these things, then the issue may lay in the water pump.

An easy way to test for a leaky water pump is to check underneath your car for liquids after it has been parked overnight. If the pavement is dark, you may want to put a large sheet of white paper under the vehicle at the beginning of the night so that you can easily discern the color of the liquid. If you do spot fluids with green or red hues, this can indicate that the water pump has a leak.

Now it's time to pop the hood and get your hands dirty. Make sure that the engine is cool before you begin, as coolant can reaches temperatures of nearly 200 degrees Fahrenheit when the engine is running.

Locate the water pump and inspect it for any visible signs of leaks. The next thing you'll want to check is the water pump pulley, which delivers power from the engine to the pump by way of the belt. Get a grip on either end of the pulley and see if you can wiggle it around. A feeling of looseness can indicate that the bearings are wearing out, and you will likely need to replace your water pump.

The pump uses centrifugal force to move the coolant, and this force is created by an impeller, which can come loose from the pump. Many late-model vehicles use plastic impellers, which can wear down easily, especially if the coolant is dirty or abrasive debris has found its way into the cooling system. A damaged impeller will not necessarily cause leaks, but it could significantly reduce the water pump's efficiency and cause the system to send an insufficient amount of coolant through the engine.

Not all vehicles will allow easy access to the water pump, and when the pump is driven by the timing belt, chances are that it will be installed inside the engine. A good time to consider replacing the water pump is when you are going to be servicing the timing belt. If work is needed on another component of the cooling system, the coolant will need to be drained, so this can be another golden opportunity to replace the pump.