Toyota 16100-49755 Pump Assembly

Water pump failure can cause overheating and serious damage to the engine. There are three ways to check the operation of the water pump while it is installed on the engine. If any one of the three following quick checks cast suspicion on the water pump, it should be replaced immediately. Start the engine and warm it up to normal operating temperature. Squeeze the upper radiator hose. If the water pump is working properly, you should feel a pressure surge as the hose is released. A seal protects the water pump impeller shaft bearing from contamination by engine coolant. If this seal fails, weep holes in the top and bottom of the water pump snout will leak coolant when the vehicle is parked. If the weep hole is leaking, shaft bearing failure will follow. Replace the water pump immediately. Besides contamination by coolant after a seal failure, the water pump impeller shaft bearing can also be prematurely worn out by an improperly tensioned drivebelt. When the bearing wears out, it emits a high pitched squealing sound. If such a noise is coming from the water pump during engine operation, the shaft bearing has failed. Replace the water pump immediately. To identify excessive bearing wear before the bearing actually fails, grasp the water pump pulley and try to force it up and down or from side to side. If the pulley can be moved either horizontally or vertically, the bearing is nearing the end of its service life. Replace the water pump.