Thermostat Inspection

Thermostat Inspection

Thermostat Removal and Installation

- Make sure that air bleed valve (1) of thermostat is clean.
- Check to make sure that valve seat (2) is free from foreign matters which would prevent valve from seating tight.
- Check thermostat gasket (3) for breakage, deterioration or any other damage.





- Check thermostatic movement of wax pellet as follows:

a Immerse thermostat (1) in water, and heat water gradually.
b Check that valve starts to open at specific temperature.

Temperature at which valve begins to open
80 - 84 °C (176 - 183 °F)

Temperature at which valve become fully open
95 - 97 °C (203 - 206 °F)

Valve lift
More than 8 mm (0.31 in.) at 95 °C (203 °F)

If valve starts to open at a temperature substantially below or above specific temperature, thermostat unit should be replaced with a new one. Such a unit, if reused, will bring about overcooling or overheating tendency.