VIN L

Engine Coolant Thermostat Replacement (LGH)

Removal Procedure

1. Remove the upper fan shroud. Refer to Engine Coolant Fan Upper Shroud Replacement (4.3L, 4.8L, 5.3L, 6.0L, 6.2L, 7.0L) (Engine Coolant Fan Upper Shroud Replacement) Engine Coolant Fan Upper Shroud Replacement (Diesel) (Engine Coolant Fan Upper Shroud Replacement).
2. Remove the intake manifold. Refer to Intake Manifold Tube Replacement (LMM) (Intake Manifold Tube Replacement).
3. Drain the cooling system. Refer to Cooling System Draining and Filling (Static Fill) (Cooling System Draining and Filling (Static Fill)) Cooling System Draining and Filling (Vac N Fill) (Cooling System Draining and Filling (Vac N Fill)) Cooling System Draining and Filling (Static Fill LGH) (Cooling System Draining and Filling (Static Fill VIN L)).
4. Remove the radiator inlet hose. Refer to Radiator Inlet Hose Replacement (LU3, LR4, LM7, LQ4) (Radiator Hose)Radiator Inlet Hose Replacement (Diesel) (Radiator Hose).
5. Disconnect the turbocharger coolant feed pipe retaining bracket bolt. Refer to Turbocharger Coolant Feed Pipe Replacement (LGH) (Turbocharger Coolant Feed Pipe Replacement).




6. Remove the fuel pressure valve bracket bolt (1) and reposition the fuel line (2).




7. Remove the thermostat bolts (1) from the engine coolant outlet pipe (2).




8. Remove thermostat (1) and thermostat (2) from the engine coolant thermostat housing.

Inspection Procedure

1. Inspect the thermostats for sticking, cracks, and/or leakage of wax.
2. Replace the thermostats if damage is found.
3. Clean the thermostat housing and thermostat housing cover sealing surfaces.

Installation Procedure





Note: The rear thermostat (2) has 2 vent valves (3). Install the vent valves towards the rear of the engine.

1. Install thermostat (1) and thermostat (2) with seals, to the thermostat housing.





Caution: Refer to Fastener Caution (Fastener Caution).

2. Position the thermostat housing (2) and install the bolts (1). Tighten to 25 Nm (17 lb ft).
3. Connect the turbocharger coolant feed pipe retaining bracket bolt. Refer to Turbocharger Coolant Feed Pipe Replacement (LGH) (Turbocharger Coolant Feed Pipe Replacement).




4. Position the fuel pressure valve bolt (1) and fuel line (2) to the thermostat housing and tighten to 25 Nm (17 lb ft).




5. Compress the clamp and connect the radiator inlet hose to the thermostat housing.
6. Install the intake manifold tube. Refer to Intake Manifold Tube Replacement (LMM) (Intake Manifold Tube Replacement).
7. Install the upper fan shroud. Refer to Engine Coolant Fan Upper Shroud Replacement (4.3L, 4.8L, 5.3L, 6.0L, 6.2L, 7.0L) (Engine Coolant Fan Upper Shroud Replacement) Engine Coolant Fan Upper Shroud Replacement (Diesel) (Engine Coolant Fan Upper Shroud Replacement).
8. Fill the cooling system. Refer to Cooling System Draining and Filling (Static Fill) (Cooling System Draining and Filling (Static Fill)) Cooling System Draining and Filling (Vac N Fill) (Cooling System Draining and Filling (Vac N Fill)) Cooling System Draining and Filling (Static Fill LGH) (Cooling System Draining and Filling (Static Fill VIN L)).