Thermostat: Service and Repair

Engine Coolant Thermostat Replacement (Diesel)

Removal Procedure

1. Drain the cooling system. Refer to Cooling System Draining and Filling (Vac-N-Fill Gasoline) Cooling System Draining and Filling (Vac-N-Fill)Cooling System Draining and Filling (Static Fill) Cooling System Draining and Filling (Static Fill)Cooling System Draining and Filling (Static Fill LGH, LML) Cooling System Draining and Filling (Static Fill)Cooling System Draining and Filling (Vac-N-Fill Diesel) Cooling System Draining and Filling (Vac-N-Fill).

2. Remove the upper fan shroud. Refer to Engine Coolant Fan Upper Shroud Replacement (Diesel) Service and RepairEngine Coolant Fan Upper Shroud Replacement (Mechanical) Service and Repair.

3. Remove the intake manifold tube. Refer to Intake Manifold Tube Replacement Intake Manifold Tube Replacement.

4. Remove the radiator inlet hose. Refer to Radiator Inlet Hose Replacement (Non-HP2) Radiator Inlet Hose ReplacementRadiator Inlet Hose Replacement (LGH, LML) Radiator Inlet Hose Replacement.

5. Disconnect the turbocharger coolant feed pipe retaining bracket bolt. Refer to Turbocharger Coolant Hoses/Pipes Replacement (Return to Turbocharger-LML) Turbocharger Coolant Hoses/Pipes Replacement (Return to Turbocharger)Turbocharger Coolant Hoses/Pipes Replacement (Return to Bypass Pipe-LML) Turbocharger Coolant Hoses/Pipes Replacement (Return to Bypass Pipe).





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





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





8. Remove thermostat (1) and thermostat (2) from the 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





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

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





Caution:
Refer to Fastener Caution Fastener Caution.

2. Position the thermostat housing (2) and install the bolts (1).Tighten to 25 Nm (18 lb ft).

3. Connect the turbocharger coolant feed pipe retaining bracket bolt. Refer to Turbocharger Coolant Hoses/Pipes Replacement (Return to Turbocharger-LML) Turbocharger Coolant Hoses/Pipes Replacement (Return to Turbocharger)Turbocharger Coolant Hoses/Pipes Replacement (Return to Bypass Pipe-LML) Turbocharger Coolant Hoses/Pipes Replacement (Return to Bypass Pipe).





4. Position the fuel pressure valve (2) to the thermostat housing and tighten the bolts (1) to 25 Nm (18 lb ft).

5. Connect the radiator inlet hose. Refer to Radiator Inlet Hose Replacement (Non-HP2) Radiator Inlet Hose ReplacementRadiator Inlet Hose Replacement (LGH, LML) Radiator Inlet Hose Replacement.

6. Install the intake manifold tube. Refer to Intake Manifold Tube Replacement Intake Manifold Tube Replacement.

7. Connect the turbocharger coolant feed pipe retaining bracket bolt. Refer to Turbocharger Coolant Hoses/Pipes Replacement (Return to Turbocharger-LML) Turbocharger Coolant Hoses/Pipes Replacement (Return to Turbocharger)Turbocharger Coolant Hoses/Pipes Replacement (Return to Bypass Pipe-LML) Turbocharger Coolant Hoses/Pipes Replacement (Return to Bypass Pipe).

8. Install the upper fan shroud. Refer to Engine Coolant Fan Upper Shroud Replacement (Diesel) Service and RepairEngine Coolant Fan Upper Shroud Replacement (Mechanical) Service and Repair.

9. Fill the cooling system. Refer to Cooling System Draining and Filling (Vac-N-Fill Gasoline) Cooling System Draining and Filling (Vac-N-Fill)Cooling System Draining and Filling (Static Fill) Cooling System Draining and Filling (Static Fill)Cooling System Draining and Filling (Static Fill LGH, LML) Cooling System Draining and Filling (Static Fill)Cooling System Draining and Filling (Vac-N-Fill Diesel) Cooling System Draining and Filling (Vac-N-Fill).