Diesel Data: Automotive Repair

Thermostat: Testing and Inspection

INSPECTION OF THERMOSTAT

INSPECT THERMOSTAT

HINT: The thermostat is numbered with the valve opening temperature.





(a) Immerse the thermostat in water and gradually heat the water.
(b) Check the valve opening temperature

Valve opening temperature: 80 - 84°C (176 - 183°F)

- If the valve opening temperature is not as specified, replace the thermostat.





(c) Check the valve lift.

Valve lift: 8.5 mm (0.335 in.) or more at 95°C (203°F)

- If the valve lift is less than specification, replace the thermostat.

(d) Check that the valve spring is tight when the thermostat is fully closed.