Thermostat Inspection
Make sure that air bleed valve (1) of thermostat is clean. Should this valve be clogged, engine would tend to overheat.
Check valve seat for some foreign matters being stuck which prevent valve from seating tight.
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 specification temperature.
Temperature at which valve begins to open
80 – 84 °C (176 – 183 °F)
Temperature at which valve become fully open
93 – 97 °C (199 – 207 °F)
Valve lift
More than 8 mm (0.315 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.
2. Thermometer 3. Heater