Thermostat: Service and Repair

Thermostat Replacement (4.3L)

Removal Procedure





1. Partially drain the cooling system.
2. Remove the air cleaner outlet duct.
3. Remove the throttle body bracket nuts and reposition the bracket.





4. Remove the water outlet housing mounting bolts.





5. Remove the water outlet housing from the lower intake manifold and set aside.
6. Remove the gasket or O-ring.





7. Remove the thermostat.
8. Clean all the sealing surfaces of the water outlet housing.
9. Clean the sealing surface on the lower intake manifold.

Installation Procedure

Important: In order to prevent leakage, thoroughly clean all parts and sealing surfaces.





1. Install the thermostat.





2. Install a new gasket or O-ring.
3. Install the water outlet housing to the lower intake manifold.

Notice: Refer to Fastener Notice in Service Precautions.





4. Install the water outlet housing mounting bolts.
^ Tighten water outlet housing mounting bolts to 19 Nm (14 ft. lbs.).





5. Install the throttle body bracket to the throttle body.
6. Install the throttle body bracket nuts.
^ Tighten the throttle body bracket nuts to 10 Nm (89inch lbs.).
7. Fill the cooling system.
8. Inspect for coolant leaks.