How to Repair a Duramax Diesel Water Pump

The Duramax diesel engine commands about 680 miles per 36-gallon tank of gas, and offers more power for towing. Some of the Duramax diesel engines can run on B20 biodiesel, which is composed of 20 percent biodiesel mixed with regular diesel. The water pump in the 6.6-liter workhorse must be in good condition, especially if you use the truck for heavy-duty towing.

Instructions

1

Remove the left front fender wheelhouse inner panel, using the appropriate socket. Slide the drain pan under the radiator petcock. Open the petcock and remove the radiator cap to allow the coolant to drain. Remove the fan shroud, using the appropriate socket.

2

Loosen the clamps on the radiator hoses at the engine, using the screwdriver. Prop the hoses out of the way. Remove the thermostat housing crossover, using the appropriate socket.

3

Locate the yellow dot on the fan clutch hub. Matchmark the water dot with the water pump pulley. Loosen the accessory drive belt tensioner, using the appropriate socket, by rotating the tensioner toward the engine. Lift the belt off the pulleys.

4

Remove the fan clutch-to-water pump pulley nuts. Lift the fan and clutch as an assembly out of the engine. Remove the crankshaft pulley retaining bolts, using the appropriate socket, then pull the pulley off the balancer. Remove the balancer retaining bolt and washer. Install the balancer puller, turn the puller clockwise to press the pulley off the crankshaft.

5

Remove the water pump outlet pipe-to-water pump nuts, using the appropriate socket. Remove the engine wiring harness retainer from the inner stud. Unbolt the water pump bolts, remembering their locations, as they are different sizes. Pull the water pump and its gasket off the engine.

6

Lubricate the water pump O-ring with engine oil. Fit the O-ring onto the new water pump. Install the water pump and tighten the bolts to 15 foot-pounds of torque. Clean the water pump outlet mating surface, using a shop rag and screwdriver. Install a new water pump-to-water pump outlet gasket and the outlet. Tighten the nuts to 15 foot-pounds of torque.

7

Reinstall the thermostat housing crossover. Reinstall the crankshaft balancer, using the puller --- turn the puller counterclockwise to reinstall the balancer. Reinstall the crankshaft pulley and tighten the bolts firmly. Reinstall the fan clutch, serpentine belt and fan shroud. Reinstall the left front fender wheelhouse panel.

8

Close the petcock on the radiator. Refill the radiator with 50/50 coolant. Start the vehicle and allow it to run until the thermostat opens --- the coolant level in the radiator will drop. Top off the radiator with coolant. Inspect the water pump for leaks. Reinstall the radiator cap.