Anyone have issues with overheating? Riding in mud with lots of water around, there are no problems. Riding long, damp trails seems to cover the radiator and reduces cooling. While riding, the air flow keeps everything in check. Once stopped, the fan just can't keep it cool and steam comes out the overflow tube. Any radiator or oil additives to keep it running cooler? Different fan? Any solutions would be appreciated.

 

there a thing called liquid ice. its some pretty good stuff. but you need to figure out why your atv is overheating in the first place. take your radiator out and really give it a good cleaning im willing to bet you have mud caked to the front of the radiator that you cant see.

 

With it being a 2006 I would:

Buy a radiator flush & fill kit and flush out the radiator and engine block, or have a cycle shop do it.
Remove radiator and pressure wash it squirting from front to back. If no pressure washer, use the hose at the local car wash.
Replace thermostat
Replace radiator cap
Replace all radiator hoses.
Clean radiator housing area on frame of quad.
Clean fan blades
Refill with fresh anti freeze and Engine Ice

If still running hot

Replace fan motor
Replace water pump.

HTH

 

I assume that you have checked the level of water in the radiator. The first thing that I did with my 06 500 was add the overflow bottle that you find on the 650 and 700. You can get the bottle from AC and it will fit right in. Just they didn't put it on the 500.
First thing to check is if there is blockage around the radiator. Additive is not the problem since the system will work. Have you added water while on the trail that may have had dirt or some thing in it that is blocking the tube ways. Sound like the only half the the radiator is working. Does not sound like the fan is not working if it is ok when riding since the fan should not need to run when seating, my fan does not run when seating unless I have been running hard and then stop and has not come back to normal temp yet. Take the thermostat out and put it in boiling water in a dish and see if it will open when at the temp of the stat rating. If it opens it should be good. If the above don't work get a radiator cleaner at the auto store and put in and flow the directions. Not likely it is the pump or would do it when running and system would be even warmer. If this does not work repost again.

 

Thanks for the ideas to find the root cause.