A few easy tests that you can do yourself will determine if your GMC water pump is failing and needs replacement. Often, a water pump begins to fail because of too-tight or too-loose pulley belts. To check for that, take a hold of the ends of the pulley and see how loose the belt is; if there is any 'give' when you try to rock the belt around, then it is a sign that the bearings have deteriorated. The bearings are vital for keeping the water pump's shaft rotating freely in place. You can also hear the sound of a bad bearing; it's a growling, grinding noise that comes from the water pump pulley. To determine if the noise is coming from the water pump, remove the fan belt and turn on the engine. If the sound is gone, then you know that the GMC water pump is approaching failure. To make an initial diagnosis on whether the problem is with the coolant circulation, see what happens when you start your car and remove the radiator cap. If you see now fluid moving through the radiator and your car overheats, then the problem can be either with the thermostat or water pump, which control circulation. And of course, a quick visual check to see if any coolant is leaking will help determine whether your GMC water pump needs replacement. If so, order your GMC water pump here, and be assured that you will be purchasing a well-engineered component that will keep your car engine cool for a long, long time.