A water pump, whether on a car, truck or yard equipment, will malfunction after time, whether it is a leak or the bearings in the pump. If the pump leaks, you will run low on water, which could cause the engine to overheat. If the bearings malfunction, the water pump will grind and won't pump enough water or won't pump fast enough to push the water -- coolant -- through the radiator, which also causes the engine to overheat.
Things You'll Need
- Drain pan
- Set of sockets
- Shop rags
- Plastic scraper
- RTV silicone
Slide the drain pan under the radiator petcock. Ensure that the engine is cold, then open the petcock and allow the coolant to drain. If you remove the radiator cap, the coolant will drain faster. Discard the coolant in an appropriate manner.
Loosen the hose clamps on the bypass hose on the water pump, if your application has a bypass hose. Pull the bypass hose off the water pump. If your application has a manual fan, remove the fan shroud retaining bolts, then push the fan shroud over the fan. Break the fan bolts loose, but do not remove them.
Loosen tension on the accessory drive belts. If the engine has a serpentine belt, rotate the tensioner toward the center of the engine and lift the belt off the pulleys. If you have V-belts, loosen the nuts and bolts in the adjusting brackets for each accessory, then push the accessory toward the center of the engine. Lift the V-belts off the accessories.
Push the fan shroud back over the fan, toward the engine. Remove the fan bolts, then lift the fan and shroud out of the engine compartment as an assembly. Loosen the clamp on the lower radiator hose at the water pump, using the screwdriver. Pull the lower radiator hose off the water pump.
Unbolt the water pump, using the appropriate sockets. Remove the water pump from the engine compartment. Most places charge a core fee for water pumps -- save the old water pump to return to the store, so you can get your core fee back.
Clean the gasket-mating surfaces, using the shop rags and plastic scraper. If the water pump uses an O-ring gasket, fit the gasket into the slot in the water pump. If the pump uses a flat gasket, smear a thin layer of RTV silicone on the pump's gasket-mating surface. Position the gasket on the pump and allow it to set for two to three minutes.
Install the water pump and tighten the bolts firmly. Slide the fan and shroud into place. Push the shroud toward the engine and tighten the fan bolts firmly. Pull the shroud into place and bolt it to the radiator support. Reinstall the accessory drive belts and the water bypass hose. Reinstall the lower radiator hose. Close the petcock on the radiator. Fill the radiator with the appropriate mix of coolant and water -- see your owner's manual for this information. Leave the radiator cap off.
Start the vehicle and allow it to come to operating temperature. Check for leaks while you are waiting. When the thermostat opens, the coolant in the radiator will lower -- top off the radiator as needed.