Thermostat Inspection
Thermostat InspectionReference: 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.
