GM 12553405
Thermostat Housing

Service and repair work on the Thermostat Housing starts with disconnecting both the battery negative cable and the auxiliary battery terminal. First drain the Radiator coolant before removing both the air cleaner unit and the Turbocharger's air duct. The procedure begins by removing both the nut on the dipstick tubes and the stud from the fuel bleed valve at the Thermostat Housing. Start by disconnecting the A/C Compressor then unplug the Coolant Temperature Sensor wiring and detach the heater hose and by-pass hose and upper Radiator Hose from the Thermostat Housing crossover. Once you remove the studs and bolts holding the Thermostat Housing crossover to the engine you can extract the crossover while cleaning down both sealing surfaces. Install new gaskets before hanging the Thermostat Housing crossover back into place then torque the bolts and studs to 47 nm (35 ft. Lbs.). Reinstall the upper Radiator Hose and the by-pass hose and heater hose and reconnect the electrical connector linking to the Coolant Temperature Sensor. The A/C Compressor should be installed next along with securing the fuel bleed valve with its stud and dipstick tubes using the nut. Reconnect the battery negative cable to both the auxiliary terminal along with the main battery terminal. Open the surge tank cap while you remove the bleed screw from the Thermostat Housing then add anti-freeze into the surge tank until steady air flow emerges from the bleed screw before screwing it shut and bringing the surge tank to its correct fluid level. After inspecting for coolant leaks you should reinstall the air intake duct and air cleaner assembly.

Reinstall the coolant recovery reservoir and put back the air cleaner and duct.

Remove the bolts attaching the thermostat housing to the thermostat.

Clean the gasket mating surfaces.

Partially drain the coolant and remove the coolant recovery reservoir.