Thermostat, Engine Cooling

Use a tempil stick in order to find the opening and the closing temperatures of the coolant thermostat.
J 24731-188 tempil stick melts at 87°C (188°F). The thermostat should begin to open.
J 24731-206 tempt stick melts at 97°C (206°F).
The thermostat should be fully open.
Replace the coolant thermostat if it does not operate properly between this temperature range.