Toyota 16100-49755 Engine Water 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.

Disconnect the cable from the negative terminal of the battery. Caution: If the stereo in your vehicle is equipped with an anti-theft system, detaching the cable. Drain the coolant. Loosen the alternator pivot nut and the power steering pump nut, then pivot the alternator and the power steering pump in towards the engine so that the drive belts are slack. Turn the air cleaner assembly housing up out of the way. Disconnect the upper radiator hose. Remove the four fan shroud bolts. Remove the fan clutch unit. Also remove the water pump pulley and (if equipped) belt guide. Remove the bolts/nut(s) which secure the water pump unit to the front of the engine. Place a pan under the water pump to catch any remaining coolant, then pull off the water pump and gasket. If it's stuck, tap it gently with a wood hammer handle. If you plan to reuse the same pump, do NOT strike it with a metal object. Remove all traces of old gasket material and sealant. The gasket mating surfaces of the pump and block (or pump body on 1979 through 1981 models) must be free of old gasket material, or the pump may leak - but be careful not to gouge the mating surfaces when scraping off the old gasket material. The gasket mating faces of the pump and the pump body (1979 through 1981 models) or the engine block (1982 and later models) must be spotless or they'll leak. Installation is the reverse of removal. Be sure to use a new gasket and tighten the bolts and nut(s) securely. Adjust the drivebelt tension. If the belt is too tight, it will put a strain on the water pump and alternator bearings. If the belt is too loose, it will slip and wear rapidly, causing possible engine overheating and low alternator output. Add coolant. Connect the cable to the negative terminal of the battery. Start the engine and check the water pump and hoses for leaks.