With the GMC water pump circulating the coolant in your engine, the temperature can be maintained at a constant level. This is another engine component that has a polymer seal that will wear out over time. The GMC water pump is located in the center front section of the engine. It is easy to spot on older models but the newer ones do have accessories and shrouds covering it. A GMC owner will know there is a problem when they notice a small puddle of coolant under this engine component. The seal is located on the shaft with the impeller at one end and the fan pulley at the other. There is a small hole at the bottom of the water pump that permits the coolant to leak out when the seal fails. When the seal on the water pump fails, not only is there a loss of coolant but there is a danger that in time the movement of the pulley will increase. For GMC trucks with the cooling fan connected to this pulley, the movement has been known to be so great that the fan can be driven into the radiator causes the repair job to be more extensive and costly. The replacing of the water pump is a simple and straight forward procedure. The most difficult part of this process is removing all of the other components on the front of the engine so you can access the water pump on your GMC truck. This does require time to complete but it is necessary for the longevity of your engine to be maintained. The only problem most technicians have is removing all of the old gasket material from the engine block so a good seal can be made with the new pump.