The inclusion of the Volkswagen water pumps on a vehicle of this automaker means it is liquid-cooled. This type of cooling system has not always been present on Volkswagen models in the past, but today it is standard equipment. The water pump mounted to the exterior of your Volkswagen engine draws coolant from the radiator through the bottom coolant hose. Inside of the Volkswagen water pump is an impeller that circulates the coolant into the engine. It is the connection where the impeller shaft protrudes from the housing of the pump that has polymer seal on it that fails in time. This seal is held in place to keep the coolant inside of the cooling system. Over time this seal will begin to split and crack as all polymer components on a vehicle does. When the seal on the impeller shaft of the water pump ruptures the coolant will begin to appear through the hole in the bottom of the pump. This is the first indication that there is a problem with the pump and it is in need of being replaced. The changing of a water pump is a basic procedure most owners of a Volkswagen can perform themselves in a day. The most difficult part of this repair procedure is remembering where all of the components are located once they are removed so access to the water pump can be made. Remember this is a coolant component that is directly mounted to the engine block. Because of this the drive belts and radiator shrouds, to name a few of the components, that are mounted in front of it have to be removed first. If the exact order and placement of these components can't be remembered, then the exploded view of this section of the engine in the service manual that can be used as a reference.