The water pump is essential to keeping any car engine cool, as it delivers the engine coolant. The pump is one of the components powered by the engine drive belt and is mounted near the power steering pump. The Buick LeSabre is a full-size car, so the engine compartment is large enough for you to access the pump with little interference from other parts. There might be very small variances in the process depending on the engine type.
Disconnect the car's negative battery cable.
Unscrew the petcock at the lower-left corner of the radiator and drain the engine coolant into a large container. Check the quality of the coolant and save it only if it is clean.
Unbolt the power steering pump using your wrench and position it aside if it is in the way of the water pump/pulley. Leave the hoses connected to the pump and do not bend or kink them.
Loosen the bolts on the water pump pulley while the drive belt is still connected. You may need to wedge a screwdriver in between two other bolts to keep it in place while loosening another bolt with a flare-nut wrench.
Rotate the drive belt tensioner counterclockwise with your wrench to loosen the drive belt and remove it from the pulleys.
Unbolt and remove the water pump pulley.
Remove the water pump pulley's bolts with your wrench and remove the pump.
Clean and remove all corrosion and sealant from the pump's bolts and the engine's mounting holes with rags and acetone. Remove all of the gasket material using a gasket scraper.
Apply a thin coat of RTV sealant to the new gasket on its engine side and to the mating surface of the replacement water pump, then connect the gasket to the pump. Hold the gasket in place using some of the mounting bolts.
Connect the pump to the engine block and tighten its bolts by hand, then tighten them the rest of the way with your wrench in quarter-turn increments. Tighten the short bolts to 96 to 132 inch-pounds and then the long ones to 22 to 29 foot-pounds.
Reconnect the water pump pulley with its bolts, tightening them to 108 to 132 inch-pounds, and then reinstall the drive belt, making sure it follows the same path along the pulleys as before.
Reconnect the power steering pump if needed.
Refill the engine coolant, using fresh antifreeze and water if needed. Fill it up to the base of the radiator neck and then add more to the lower mark of the reservoir.
Reconnect the battery cable.
