Thermostat: Service and Repair

Engine Coolant Thermostat Replacement (LY7)

Removal Procedure

1. Partially drain the cooling system. Refer to Cooling System Draining and Filling (L26, LY7 GE 47716 Fill) (Service and Repair)Cooling System Draining and Filling (LY7 Static Fill) (Service and Repair).

Important: Do NOT separate the upper and lower intake manifolds.


2. Remove the upper intake manifold with the lower intake manifold. Refer to Lower Intake Manifold Replacement (Service and Repair).
3. Disconnect the surge tank hose from the thermostat.




4. Remove the coolant pipe/thermostat housing bolt (1).
5. Remove the coolant pipe bolt (3).
6. Remove the coolant inlet pipe from the thermostat housing.
7. Remove and discard the coolant pipe O-ring seal (2).




8. Remove the thermostat bolts.
9. Remove the thermostat and discard the thermostat seal.

Installation Procedure




1. Install the thermostat with a NEW thermostat seal.

Notice: Refer to Fastener Notice (Fastener Notice).

2. Install the thermostat bolts.

Tighten the thermostat bolts to 10 N.m (89 lb in).




3. Install the coolant pipe, NEW seal (2), and fasteners (1 and 3). Refer to Radiator Outlet Pipe Replacement (LY7) (Service and Repair).
4. Install the surge tank hose to the thermostat.
5. Install the upper intake manifold with the lower intake manifold. Refer to Lower Intake Manifold Replacement (Service and Repair).
6. Fill the cooling system. Refer to Cooling System Draining and Filling (L26, LY7 GE 47716 Fill) (Service and Repair)Cooling System Draining and Filling (LY7 Static Fill) (Service and Repair).