Toyota 16100-19226 Engine Water Pump Assembly

A failure in the water pump can lead to engine damage due to overheating. To check the water pump while it is installed on the engine, there are three methods. One way is to squeeze the upper radiator hose while the engine is running at normal temperature. If the water pump is working properly, a pressure surge should be felt when releasing the hose. However, caution should be taken to avoid the fan blades, as they can turn on unexpectedly. Another method is to check for coolant leakage from the weep hole on the water pump. A flashlight may be needed to locate the hole from underneath. Additionally, a howling sound at the drive belt end of the engine while running may indicate water pump shaft bearing failure. Rocking the water pump pulley can detect shaft wear, and if there is play in the shaft, the water pump should be replaced. Finally, the pump shaft should be turned by hand to check for roughness in the bearing. If roughness is felt, the pump should be replaced.

To remove the water pump, start by disconnecting the battery cable and draining the cooling system. Remove the right-hand splash shield and HAC valve if applicable. Take off the accessory drive belt and intake manifold brace, removing the AS valve first on certain models. Disconnect the water by-pass on carbureted models and remove the oil pan dipstick. Remove hoses from the inlet pipe and detach the pipe from the water pump. Remove the alternator and adjusting bar, checking the by-pass pipe for leaks. Replace the O-ring or hose if necessary. Finally, remove the water pump by removing the bolt and two nuts, tapping it if stuck. For installation, clean the surfaces, install a new O-ring, and apply soapy water to the O-rings. Apply gasket sealant to the pump groove and install it with the bolt and nuts. Reinstall all parts and refill the cooling system, checking for leaks.