GM 12703898
Water Pump

Before working on water pumps for 4.8l, 5.3l, and 6.0l engines drain the cooling system then detach air cleaner, fan clutch, and accessory Drive Belt pieces. You need to disconnect the inlet hose first at both clamps before pulling it free from the Water Pump. Next remove the outlet hose by unclipping its clamps. After that take off the heater inlet hose clamp and disconnect the hose from the heater. Take out the Water Pump by removing the bolts first and then taking out the unit with its gaskets for proper disposal. Apply new gaskets when you install the Water Pump while keeping all components clean from oil and other debris. Apply new Water Pump gaskets before installing the Water Pump. Secure its bolts at 15 nm and tighten them to 30 nm during final torque. Fasten the heater hose inlet first then add the outlet and inlet clamp. Reattach the belt for the accessories, fan and compressor parts, and place the air filter unit back in place. Also add fluid to the cooling system.

You need to empty the cooling system first then uninstall the air cleaner, fan blade, heaters' hoses before taking off their brackets from the Water Pump. Take out the Water Pump assembly by first removing its bolts and then the accessory tensioner pair. Discard the used gaskets while installing new ones over the pump. Before installing the Water Pump with new gaskets ensure all gasket contacts are clean. Then use Water Pump bolts to fasten the parts first to 15 nm (11 ft. Lbs.) and then to 30 nm (22ft lbs.). Fasten the heater inlet hose to its clamp then connect both outlet and inlet hoses to their clamps. Place back the accessory Drive Belt tensioner and bolts while tightening them to 50 nm (37 ft. Lbs.). Install the accessory Drive Belt, fan blade, and air cleaner assembly. Finally, fill the cooling system.

The first step to replace a Water Pump is draining the cooling system while also removing air cleaner assembly components including Fan Clutch and accessory Drive Belt. Move the inlet hose clamp aside and detach the inlet hose before transferring the outlet hose clamp and taking out the outlet hose. You should now relocate the heater inlet hose clamp to disconnect the hose. Take out the Water Pump while removing its bolts and discard the original gaskets. Put new gaskets on the Water Pump before installation and make sure all sealing surfaces stay dry. Put on the Water Pump with new gaskets first, screw in all Water Pump bolts, but leave them at 15 nm (11 ft. Lbs.) before torquing them to their final value of 30 nm (22 ft. Lbs.). Reposition the heater inlet hose with its clamp before connecting the outlet hose with its clamp and finally installing the inlet hose and its clamp. After these pieces you reattach the accessory Drive Belt, fan blade, clutch assembly, air cleaner assembly and complete filling the cooling system.

Tighten them first to 15 Nm (11 ft. lbs.) and then to a final torque of 30 Nm (22 ft. lbs.).

Use the Fan Clutch Remover and Installer (J 41240) to hold the water pump pulley while installing and tightening the pulley bolts to 25 Nm (18 ft. lbs.).