Thermostat, Engine Cooling
Use a tempilstick in order to find the opening and the closing temperatures of the coolant thermostat.* J 24731-188 tempilstick melts at 87°C (188°F). The thermostat should begin to open at 90°C (194°F).
* J 24731-206 tempilstick melts at 97°C (206°F). The thermostat should be fully open at 107°C (225°F).