12. COOLING SYSTEM ATV 300/250 THERMOSTAT INSPECTION Suspend the thermostat in a pan of water over a burner and gradually raise the water Thermostat temperature to check its operation. Technical Data Thermometer Begins to open 802 Full-open 90 Valve lift 3.54.5 mm (0.140.18 in) O-ring · Do not let the thermostat touch the pan as it will give a false reading. · Replace the thermostat if the valve stays open at room temperature. ·Test the thermostat after it is opened for about 5 minutes and holds the temperature at 70. THERMOSTAT INSTALLATION The installation sequence is the reverse of removal. Replace the O-ring with a new one and Thermosensor apply grease to it. Fill the cooling system with the specified coolant. (page 3-20) 12-12