GM 12685257 Water Pump Assembly (W/ Manifold)

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To remove the 4.3L V6, 5.3L, and 6.2L V8 engines, start by disconnecting the cable from the negative terminal of the battery. Then, drain the coolant and remove the air intake duct and resonator assembly. Next, remove the drivebelt and center the water pump pulley holes over the water pump mounting bolts. Remove the water pump and gasket from the coolant manifold, and clean the mounting surface on the engine and water pump. Clean the mounting bolt threads and threaded holes if necessary. Compare the replacement pump with the old one to ensure they're identical. Place the gaskets and water pump into position, and tighten the bolts to the torque specification. The remaining installation steps are the reverse of the removal procedure. Refill the engine with coolant, run the engine, and check for leaks. For the 6.0L V8 removal, follow similar steps, but also remove the fan, fan clutch, water pump inlet hose, water pump outlet hose, and coolant air bleed hose if necessary. Remove the thermostat housing if a new water pump is to be installed. Unbolt the water pump, clean the mounting surface, compare the replacement pump, and install the gaskets and water pump. Tighten the bolts, complete the remaining installation steps, refill the engine with coolant, run the engine, and check for leaks.