2006 Arctic Cat DVX 400 Service Manual, Page 90Get this manual
CThe thermostat should start to open at 75C (167F)DIf the thermostat does not open, it must be replaced3Inspect all coolant hoses, connections, and clamps for deterioration, cracks, and wearNOTE: All coolant hoses and clamps should be replaced every four years REMOVING
1Drain the engine coolant and engine oil; then disconnect the radiator hose
INSTALLING
1Place the thermostat into the thermostat housing; then secure the thermostat housing to the cylinder head with the two cap screws2Slide the upper hose onto the thermostat housing; then secure with the hose clamp3Fill the cooling system (1.2 or 1.3 U.Sqt) with antifreezeCheck for leakageSP295