How to Replace a Thermostat on a Polaris ATV

by Alan Sembera

If your Polaris All-Terrain Vehicle (ATV) is overheating or not warming up quickly enough, you may need a new thermostat. The vehicle's thermostat controls the flow of coolant to the engine. If you get too much flow, your ATV may not warm up properly. If you don't get enough flow, your engine may overheat. Polaris manufactures several models of ATVs, so check the service manual available at the Polaris website for the proper replacement part.

Step 1

Locate the main coolant hose and follow it to the thermostat housing on the engine block, after allowing the engine to cool down completely.

Step 2

Place a clean drain pan or bucket under the thermostat housing to catch any coolant that leaks out during the replacement.

Step 3

Loosen the clamp that attaches the main coolant hose to the thermostat coupling with a screwdriver, then remove the hose. Make sure any spilled coolant goes into the drain pan.

Step 4

Remove the two bolts holding the thermostat housing to the engine block with a socket wrench.

Step 5

Note the position of the thermostat and pull it out of the opening.

Step 6

Remove the old gasket from around the opening. Scrape off any that is stuck to the surface, making sure no pieces go into the opening.

Step 7

Place the new gasket over the opening.

Step 8

Insert the new thermostat into the opening. Make sure it is in the same position as the old thermostat. If the thermostat comes with a bell-like valve opening, make sure the opening is to the top.

Step 9

Replace the thermostat housing, bolts and coolant hose.

Step 10

Pour any spilled coolant back into the radiator or overflow reservoir.

Step 11

Start the engine and check for leaking coolant.

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