Toyota 16100-79445 Engine Water Pump Assembly

To replace the water pump, first disconnect the negative battery cable. For PreRunner or 4WD models, remove the forward under-vehicle splash shield. Drain the cooling system, and if applicable, remove the engine cover. Remove the drive belt, Cooling Fan Assembly, and for four-cylinder models, remove the alternator, drive belt tensioner, and water pump bolts. Clean the gasket mating surfaces, install a new gasket and water pump, and tighten the bolts to the specified torque. Refill the cooling system, start the engine, and check for leaks. For V6 models, remove the air filter assembly, oil cooler hoses, coolant bypass hoses, water inlet assembly, idler pulleys, and alternator. Set aside the A/C Compressor, and remove the drive belt tensioner and water pump bolts. Clean the gasket surfaces, install a new gasket, water pump, and a new O-ring on the water pump. Install the water inlet assembly, tighten the fasteners to the correct torque, refill the cooling system, start the engine, and inspect for leaks.

For four-cylinder engines, Disconnect battery, drain cooling system. Remove power steering, alternator/water pump, and AC belts. Remove fan shroud, assembly, and water pump pulley. Disconnect radiator inlet and bypass hoses. Remove water pump, clean gasket surface. Install in reverse order with new gasket. Refill cooling system, check for leaks. For V6 engines: Disconnect battery, drain cooling system, remove timing belt. Remove alternator bracket, thermostat housing, disconnect oil cooler hose if present. Remove water pump, disconnect radiator hoses. Clean gasket surfaces, apply sealant to water pump. Install in reverse order, tighten bolts, refill cooling system, check for leaks.

A failure in the water pump can lead to engine damage due to overheating.

With the engine running and warmed 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.