2010 Polaris Sportsman 850 Service Manual, Page 98Get this manual
COOLING SYSTEM THERMOSTAT
Removal (Engine Installed)
123Drain coolant so the coolant level is below the thermostat housing (see "Coolant DrainRadiator Removal")Remove the (2) screws from the rear portion of the air boxLocate the thermostat housing on the left side of the valve cover next to the fuel railShown with air box removed for clarity
TROUBLESHOOTING
Cooling System
Overheating Low coolant level Air in cooling system Wrong typemix of coolant Faulty pressure cap or system leaks Restricted system (mud or debris in radiator fins causing restriction to air flow, passages blocked in radiator, lines, pump, or water jacket, accident damage) Engine running lean (fuel system restriction) Fuel pump output weak Electrical malfunction
Thermostat Housing 4Remove the (2) screws and lift the housing up far enough to remove the thermostat with the coolant line still attached