GM 12481997 Water Pump Kit

Disconnect the negative battery cable. Drain the radiator. Reaching inside the radiator shroud, remove the bolts which secure the fan to the water pump hub. Remove the fan and spacer(if equipped). A thermostatic fan clutch must remain in the "in car"osition. If equipped with a two-piece radiator shroud, remove the upper half of the shroud for better access to the water pump. It is now necessary to loosen and remove all drivebelts from the water pump pulley. The number of belts will depend upon model, year.and equipment Loosen the adjusting and pivot bolts of each affected component (air pump, alternator, air conditioning compressor) and push the component inward to loosen the belt enough to be removed from the water pump pulley. Disconnect and remove all mounting brackets which are attached to the water pump. These may include on late model vehicles the alternator, air conditioning compressor, and power steering brackets. Disconnect the lower radiator hose, heater hose, and bypass hose at the water pump. Remove the remaining bolts which secure the water pump to the front cover of the engine. Lift the water pump housing straight out of the front cover and then away from the engine. If installing a new or rebuilt water pump, transfer all fittings and studs to the new water pump (If a replacement pump is used, transfer all hose fittings from the old pump to the new). Clean the gasket surfaces of the front cover completely using a gasket scraper or putty knife. Use a thin coat of gasket sealant on the new gaskets and install the new water pump. Place the pump into position on the front cover and secure loosely with the bolts. Do not torque-tighten these bolts until all brackets have been installed to their original position on the water pump. Tighten all water pump bolts to torque specifications. Install the engine components in the reverse order or removal,tightening the appropriate fasteners to torque specifications. Adjust all drivebelts to the proper tension. Connect the negative battery cable and fill the radiator with a mixture of ethylene glycol antifreeze and water in a 50/50 mixture. Start the engine and allow to idle until the upper radiator hose gets hot. Check for leaks. With engine hot, fill with more coolant mixture until the level is at the bottom of the filler neck. Install radiator cap and check coolant level periodically over the next few miles of driving.

A failure in the water pump can cause overheating and serious engine damage because a defective pump will not circulate coolant through the engine. There are three ways to check the operation of the water pump while it is still installed on the engine. If any of the following checks indicate that the pump is defective, replaced it with either a new or rebuilt unit. Squeeze the upper radiator hose while the engine is running at normal operating temperature. If the water pump is working properly, a pressure surge will be felt as the hose is released. The water pump is equipped with a "weep" (vent) hole. If the pump seal fails, small amounts of coolant will leak through the weep hole. You will need to get underneath the water pump to see the weep hole, so raise the vehicle and place it on jackstands. Use a flashlight or a drop light to help you determine whether there is evidence of leakage from the weep hole. If the water pump shaft bearing fails, it will usually emit a squealing sound while it is running. Do not confuse drivebelt slippage, which also makes a squealing sound, with water pump bearing failure. Even before the bearing actually fails, shaft wear can be detected by grasping the pulley firmly and moving it up and down. If excessive side play is noted, the shaft or the bearing are worn and the pump should be replaced.

The third way is to listen for a squealing sound at the front of the engine while it is running. If the water pump shaft bearings fail, this sound may indicate a problem. Additionally, shaft wear can be felt if the water pump pulley is forced up and down.

Remove the water pump mounting bolts and lift out the pump. In some cases, the A/C compressor may need to be removed for clearance.

They should be loosened and removed, along with the fan blades and pulley or pulleys from the hub on the water pump shaft.

The second way is to look for water leakage from the weep or vent holes on the water pump. If a failure occurs to the bladder of the pump, small amounts of water will leak from these weep holes. It may be necessary to use a flashlight from under the car to see evidence of leakage.

A failure in the water pump can cause serious engine damage due to overheating as the pump will not be able to circulate cooled water through the engine.

Clean the mating surface on the block and apply RTV sealant to the new water pump mating surface.

Start the engine and allow it to idle until the upper radiator hose gets hot. Check for leaks. When the engine is hot, fill with more coolant mixture until the level is at the bottom of the filler neck. Install the radiator cap and periodically check the coolant level during the next few miles of driving.

If the water pump is suspect, it should be replaced with a new or factory rebuilt unit.

The coolant hoses should be disconnected from the water pump.