Removal
Drain the coolant (page 6-4).
Remove the fuel tank (page 5-50).
Remove the bolt and thermostat housing.
Remove the filler neck bolts and filler neck/thermostat housing cover.
Remove the thermostat from the housing.
If the filler neck/thermostat housing cover is to be removed, loosen the band screws and disconnect the upper radiator hose from the housing.
If the thermostat housing is to be removed, disconnect the thermosensor connector (page 5-68).
Loosen the band screws and disconnect the water hoses from the housing.
Refer to page 19-15 for thermosensor (coolant temperature indicator) information.
Inspection
Visually inspect the thermostat for damage.
Replace the thermostat if the valve stays open at room temperature.
Heat a container of water with an electric heating element for 5 minutes.
Suspend the thermostat in the heated water to check its operation.
Replace the thermostat if the valve responds at temperatures other than specified.
Thermostat begins to open: 80-84°C (176-183°F)
Valve lift: 8 mm (0.3 in) minimum at 95°C (203°F).
- Wear insulated gloves and adequate eye protection.
- Keep flammable materials away from the electric heating element.
- Do not let the thermostat or thermometer touch the pan. or you will get false readings.
Installation
Install the thermostat into the housing with its hole facing upright.
Align the thermostat flange with the groove in the housing upper surface. Make sure the thermostat is securely installed.
Install the new O-ring on the thermostat housing cover.
Install the thermostat housing cover and tighten the cover bolts.
Align the tab on thermostat housing with the groove on the frame.
Install and tighten the bolt securely.
Install the fuel tank (page 5-50).
Fill and bleed the cooling system (page 6-4).
