Duramax diesel engines have been installed in Chevrolet and GMC heavy duty trucks since 2001 and are still in production today. Vehicles that are powered by the Duramax diesel engine have been known to travel thousands of trouble-free miles; however, regular maintenance is crucial to the Duramax's cooling system. Replacement of the Duramax's water pump is necessary once a coolant leak has been detected. If the water pump should happen to fail, major engine damage can occur.
Disconnect the negative battery cables on both batteries. Place a drain pan under the radiator and remove the radiator drain plug. Once the coolant has drained from the radiator, replace the drain plug.
Remove the fan shroud and the inner fender liner on the left-hand side. Loosen and remove the nut holding the fan assembly and pull the fan out, being careful not to damage the radiator. Remove the fan clutch pulley. Use a large breaker bar to loosen the bolt holding the crankshaft harmonic balancer. Slide the balancer off the shaft and set it aside.
Remove the thermostat housing crossover to gain access to the water pump housing. Remove the nuts holding the oil cooler to the water pump cover and then remove the oil cooler. Loosen the lower radiator hose from the water pump. Loosen and remove the three water pump housing bolts, making a note of their different lengths. Remove the water pump housing and gasket. Remove the water pump housing cover to reach the water pump. Remove the water pump. Install a new "O" ring onto the new water pump and install it back into the water pump housing. Re-tighten the water pump housing bolts.
Re-attach the water pump housing to the engine block. Make sure you thread the bolts into the correct holes, as they are different lengths. Re-attach the lower radiator hose to the water pump. Install the oil cooler using the original attaching nuts. Re-install the thermostat housing crossover.
Re-install the crankshaft harmonic balancer and the fan assembly. Replace the left-side inner fender liner and the fan shroud. Re-connect the negative battery cables. Refill the radiator with a 50/50 coolant and distilled water mix. Close the radiator and start the vehicle, letting it run for several minutes. Re-tighten the connections if any leaks are detected. Re-check the coolant level and top off the radiator, if needed.
