The tube that threads into the pump can be found in one of two locations on the pumps depending on the year of the Chevette. It is sometimes threaded in down by the large lower radiator hose, and is aimed rearward. It can also be threaded in up under the water pump facing downward and slightly to the drivers side. Some pumps have two threaded ports, and some are cast with just one. They use the threaded NPT plug to block off the port you don't need. Some Chevettes have the waterpump bypass hose running on the passenger side under the exhaust manifold, and some have the return hose from the heater core running on the drivers side up over the shock tower and back to the pump.Both of the threaded ports are suction return ports that allow the water pump to have some place to send its constant pressure until your engine reaches operating temp and the thermostat opens allowing coolant to flow through the radiator. Without that "bypass" return hose the pump is working against itself and can cause damage to itself like cavitation. It is a needed part of the water pump system, and so should never be completely eliminated as I seen done when people eliminate their heater cores. The pump needs the return pressure flow at all times while the thermostat is shut completely.
Message Thread
« Back to index