A failure in the water pump can cause serious engine damage due to overheating as the pump will not be able to circulate cooled water through the engine. There are three ways to check the operation of the water pump while it is still installed on the engine and if the pump is suspect, it should be replaced with a new or factory rebuilt unit. With the engine warmed up to normal operating temperature, squeeze the upper radiator hose. If the water pump is working properly, a pressure surge should be felt as the hose is released. Water pumps are equipped with weep or vent holes, if a failure occurs to the bladder of the pump, small amounts of water will leak from these weep holes. In most cases, it will be necessary to use a flashlight from under the car to see evidence from this point in the pump body. If the water pump shaft bearings fail there may be a squealing sound at the front of the engine while it is running. Shaft wear can be felt if the water pump pulley is forced up and down. Do not mistake drivebelt slippage, which also causes a squealing sound, for water pump failure.