GM 12600171
Thermostat Unit

In order to replace the Thermostat of a 4.2l engine, one will initially draw the required coolant off of the Radiator, thereafter draw off the generator. Loosen the outlet hose clamp using the hose clamp pliers (J 38185) at the Thermostat Housing and take off the outlet hose. Then, unfasten the Thermostat Housing bolts and pull off the Thermostat Housing from the engine block. Clean all the Thermostat Housing surfaces and the sealing surface of the engine block. Do the final installation of the Thermostat Housing to the engine block by making sure that the fastener notice in service precautions is done, and then bolting in the Thermostat Housing using a torque of 10 nm (89 inch lbs). Apply engine coolant to the inner diameter of the Radiator Hose, connect the outlet hose to the Thermostat Housing, and tighten it with the clamp. Install back the generator, and fill the cooling system with the particular coolant and concentration, and finally, check all the surfaces for seal leakage after starting the engine.

A replacement of the thermostat on the 8.1L engine begins with draining the cooling system. Begin by relocating the inlet hose clamp on the water outlet then remove the water outlet hose. The next step requires drivers to take off the water outlet by unscrewing its two bolts. After this step the thermostat can be accessed. Installation begins by installing the thermostat followed by the water outlet. Reposition the inlet hose clamp at the water outlet followed by installing the inlet hose to the water outlet. Protect the inlet hose with the clamp in the appropriate position. Tighten the water outlet bolts to 30 Nm (22 ft. lbs.) for proper installation. Finally, fill the cooling system.

In order to replace the engine coolant Thermostat, first it is necessary to drain the cooling system using cooling system draining and filling (GE 47716) and cooling system draining and filling (Static Fill). Next, a repose of outlet hose clamp for the water pump inlet to remove the outlet hose from the water pump inlet. After that, remove the water pump inlet bolts and the water pump inlet. The o-ring seal is part of the Thermostat Housing and therefore continue removing the Thermostat Housing. For installation, first install the Thermostat Housing making sure the o-ring seal is correctly fitted on the groove. Install the water pump inlet (with Thermostat) and the water pump inlet bolts with 15 n.m (11 lb ft). Reconnect the outlet hose to the water pump inlet and locate outlet hose clamp at the water outlet. Lastly, drain the cooling system using cooling system draining and filling (GE 47716), cooling system draining and filling (Static Fill).

To exchange a Thermostat in a 4.3l engine, first remove the air cleaner and duct assembly and also partially drain the coolant and the coolant recovery container. Unplug the Radiator Hose from the Thermostat Housing. Move the bolts secured in the Thermostat Housing to the Thermostat apart; then, remove the Thermostat Housing and the Thermostat also. Sand the gasket mating surfaces and do not install the new Thermostat. Now, connect the Thermostat Housing with the Intake Manifold and bolt it using the bolts that you tighten to a torque of 25 nm (18 ft. Lbs.). Replace the Radiator Hose onto the Thermostat Housing, replace the coolant recovery reservoir, and replace the air cleaner and duct. Top off the cooling system, bleed the air in the system, and lastly, inspect the Thermostat Housing as well as the gasket for any cracks in the cooling system due to coolant leaks.

Replacing the Thermostat Housing on 4.8l, 5.3l, and 6.0l engines starts by removing the radiator outlet hose followed by taking out the Water Pump inlet bolts to detach the Water Pump inlet and Thermostat while noting the Thermostat's requirement for replacement only as an assembly with the Water Pump inlet. Installation requires placing the Thermostat and Thermostat Housing onto the Water Pump in accordance with service precautions fastener notice. After securing the Thermostat Housing bolts with 15 nm (11 ft. Lbs.) torque, reinstall the radiator outlet hose.

Separate Thermostat repair services are unavailable so installation requires changing both inlet Water Pump and Thermostat at once. Start your work with radiator outlet hose removal and Water Pump inlet bolts extraction. You need to remove the Water Pump inlet together with the Thermostat from the Water Pump itself. During installation the Water Pump inlet assembly with Thermostat should be placed onto the Water Pump according to the fastener notice in service precautions. Secure the Water Pump inlet bolts to 15 nm (11 ft. Lbs.) torque while reinstalling the radiator outlet hose.

To replace the Thermostat in a 4.3l engine, first drain the cooling system. Release the air cleaner outlet duct clamp at the mass airflow/intake air temperature (MAF/IAT) sensor and remove the positive crankcase ventilation (PCV) hose along with the air cleaner adapter nut. Pivot the air cleaner outlet duct upward till the hinge clip comes off the Throttle Body lip. Retrain the water outlet hose clamp at the water extent and pull the inlet again, the water outlet studs and the water outlet hose afterward. Remove Thermostat and clean sealing surfaces of water outlet, as well as the sealing surfaces of the Intake Manifold, discarding the o-ring seal. In case of replacement, however, take off the original Thermostat by unbolt the water outlet, leaving the o-ring seal in place. Then, put on a new o-ring seal and replace the Thermostat. Reinstall the water outlet. Attach the water outlet studs, tightening them to 25 nm (18 ft. Lbs.), and then connect the inlet hose to the water outlet and mount inlet hose clamp. Allow the hinge clip to match with the lip running down from the Throttle Body, and move the air cleaner outlet duct down to get the mounting stud into it so that you can then fit the air cleaner adapter nut and the pcv hose. Close the air cleaner outlet duct clamps on the maf/iat sensor to 4 nm (35 inches lbs), add fluid into the cooling system and check for leaks.

The replacement of the thermostat for an 8.1L engine begins with draining the cooling system. You should move the inlet hose clamp to the water outlet before removing the inlet hose from this location. Begin by unscrewing the two water outlet bolts so you can detach the water outlet . You can then remove the thermostat for replacement. Begin the installation process by adding the thermostat then the water outlet . Set all water outlet bolts to 30 Nm (22 ft. lbs.) before reattaching the inlet hose to the water outlet ensuring the hose clamp faces the outlet. Finally, fill the cooling system.

Start by draining necessary coolant from the Radiator when replacing the Thermostat on a 4.2l engine. Next, remove the generator. Deploy hose clamp pliers (J 38185) to unscrew the outlet hose clamp at the Thermostat Housing before you remove the outlet hose. After removing the bolted Thermostat Housing the technician should separate the housing from the engine block. You must completely clean both the Thermostat Housing surfaces and the engine block's sealing area. Secure the Thermostat Housing onto the engine block then follow the fastener notice before attaching the Thermostat Housing bolts until they achieve 10 n.m (89 lb in) of torque. Before installing the outlet hose onto the Thermostat Housing apply engine coolant to the inside of the Radiator Hose. Close the hose to the Thermostat Housing by tightening the clamp. Affix the generator while you add the instructed coolant and dilution rate into the cooling system. Perform an inspection for fluid leaks from all sealing surfaces when the engine begins operation.

Disconnect the surge tank hose from the thermostat.

Place the new thermostat with a new thermostat seal and tighten the thermostat bolts to 10 N.m (89 lb in).

Depress the ears on both sides, rotate the thermostat until it clears the retaining feature, release the pressure, and pull the thermostat from the housing.

Reinstall the coolant pipe with a NEW seal and fasteners (2 and 7), then reconnect the surge tank hose to the thermostat.

Remove the water pump inlet bolts and take out the water pump inlet, noting that the O-ring seal is integral to the thermostat housing.

Place a NEW O-ring seal onto the thermostat and install it, followed by the water outlet.

Reattach the outlet hose to the water pump inlet and position the outlet hose clamp at the water outlet.

It is important because oil can impair the function of the thermostat and water pump.

Remove the thermostat (305) and clean and inspect the mating surfaces of the water outlet housing O-ring seal.

Clean the gasket surfaces.

Begin by draining the cooling system.

Reattach the radiator outlet hose to the thermostat housing.

Take out the water pump inlet bolts.

Next, take out the water pump inlet bolts and then remove the water pump inlet and thermostat from the water pump.

Clean all surfaces of the thermostat housing and the sealing surface of the engine block.

Fill the cooling system with the specified coolant and concentration.

Place a NEW O-ring seal onto the thermostat and install it, followed by the water outlet.