How to Replace the Water Pump in a 1996 GMC 1500

The 1996 GMC 1500 pickup base model was offered with the 4.3-liter six-cylinder engine. The water pump for the 4.3-liter is mounted to the engine block, directly under the intake manifold, and is solely responsible for circulating engine coolant through the cooling system. When replacing the water pump, it is necessary to remove the water pump pulley and install it onto the new water pump. The 1996 GMC 1500 requires the use of Dexcool coolant, which cannot be mixed with any other type of coolant.

Instructions

Lift the vehicle hood and support it with the hood prop rod. Allow the engine to cool completely.

Loosen the radiator cap enough to vent the coolant pressure. Once the hissing noise has dissipated, remove the radiator cap. Place the drain pan under the passenger side of the radiator, directly under the drain cock. Open the drain cock by rotating it counterclockwise. Allow all the coolant to drain and tighten the radiator drain cock. Remove the drain pan and store the used coolant in a safe place until it can be recycled properly.

Remove the four bolts holding the upper fan shroud to the lower fan shroud, using the socket and ratchet. Remove the two bolts securing the upper fan shroud to the core support and remove the upper fan shroud from the engine bay.

Install the fan clutch holding tool onto the water pump pulley bolts. Place the fan clutch nut wrench onto the fan clutch nut and rotate the nut counterclockwise while holding the water pump steady to remove the fan and fan clutch assembly. Remove the fan and fan clutch from the engine bay. When storing the fan and fan clutch make sure to position the fan clutch shaft facing straight up or the fluid may leak into the fan bearing and cause it to fail.

Install the breaker bar into the square hole on the tensioner arm and rotate the tensioner counterclockwise. Make a sketch of the sepentine belt's position around items in the engine compartment. Slide the serpentine belt from around the tensioner pulley and slowly release the tensioner to its neutral position. Remove the serpentine belt from the engine compartment.

Maintain the fan clutch holding tool on the water pump pulley nuts and loosen the opposite pulley bolts with the socket and ratchet while holding the pulley stationary with the holding tool. Place the holding tool over the two loosened bolts and break loose the opposite pulley bolts. Remove the fan clutch holding tool. Remove the water pump pulley bolts and the water pump pulley.

Squeeze the pressure clamps for the water pump inlet hose on both sides with the pliers and slide the clamps to the center of the hose. Carefully remove the inlet hose from the water pump.

Remove the four water pump bolts with the socket and ratchet . Remove the water pump from the engine. Remove the water pump gaskets from the engine block and clean the water pump mating surface with the wire brush.

Clean the water pump bolt threads with the wire brush and apply a coat of thread sealant to the bolt threads. Place the water pump gaskets onto the new water pump and install the water pump onto the engine block. Install the water pump bolts and tighten to 33 foot-pounds with the torque wrench.

Install the water pump inlet hose onto the water pump and inlet pipe. Squeeze the pressure clamps and slide them down the hose. Release the pressure clamps to secure the hose to the water pump and inlet pipe.

Install the water pump pulley onto the water pump and install the water pump pulley bolts. Tighten the water pump pulley bolts to 18 foot-pounds with the torque wrench. Use the fan clutch holding tool to prevent rotation of the pulley while tightening.

Route the serpentine belt around the crankshaft pulley and engine accessories according to the sketch made previously, holding pressure at the belt tensioner. Place the breaker bar into the square opening on the tensioner arm and rotate the tensioner counterclockwise. Slide the belt around the tensioner pulley and slowly release tensioner.

Thread the fan and fan clutch onto the fan clutch shaft at the water pump pulley. Place the torque wrench into the square opening on the fan clutch wrench. Tighten the fan clutch nut to 18 foot-pounds of torque while using the holding tool to prevent the pulley from rotating.

Install the upper fan shroud and tighten the mounting bolts with the socket and ratchet. Pour fresh 50-50 DEXCOOL coolant into the radiator until it is full and the coolant level is stable. With the radiator cap off start the engine and allow it to reach operating temperature. Increase the engine speed to 3000 rpm for 1 minute and then shut down the engine. Top off the radiator until full and install the radiator cap. Fill the coolant reservoir to the warm full line.