I have a 2001 Sportsman 500 H.O. that I have boiled over twice. Fan works , radiator is clean. Only heats up when pulling hard in mountains or high temperature desert riding. Friend's non-H.O. does not heat up in same situation. Dealer says that H.O. should not run hotter than the older 500's. Anyone else had this problem ?

 

You may think the radiator is clean when it really isn't. My friends HO was overheating and his radiator looked clean to the naked eye. On a tip from another rider, he took a bottle of Simply Green and sprayed the radiator until the entire thing was soaked. He then let it sit for about 15 minutes. When he hosed it out, he was astonished at the grime and silt that came out. After that, his has never overheated again. Try it!

 

Look on this forum. There is a product out there called "wetter water" that is suppose to help your machine run cooler as well. You might try that.

 

My son had a problem with his 2000 500 sportsman it turned out to be air pockets in the system. We replaced the little elbow at the bottom of the overflow bottle because it cracked and was leaking. At a ride he was towing a broken quad and it overheated a couple times. I took it to the dealer and they told me its tough to bleed out all the air in the system you have to keep adding fluid then run the engine then add more fluid. Anyway after they were done it hasn't overheated again. If you never had a problem with the cooling system maybe it was never bleeded from the factory.

 

Hey,

Thanks for the responses . I'll try all of them. I really like the Sportsman except for this problem. I've got 1100 miles on it , and have had no other problems.

Ken

 

I like Rubie Ricks answer. My 700 and one of my son's H.0.'s did the same thing last weekend. Both the radiators looked clean but when we sprayed them out with a garden hose,( NO high pressure) lot's and lot's of mud came out. End of problem.

 

flyboy36,

You have probably solved your problem, but on my 500 sportsman, the fan sensor in the rad was acting up. It would kick in the fan but normally too late. Then the machine would overheat. In the end I changed the sensor (a $30 cdn touch) and all was well.

 

Thanks for the response "GreazeMonkey "

I've inspected and cleaned radiator, checked for leaks and air in the system , and changed the thermostat. None of these seem to be causing any problems. I haven't had a chance to run the quad hard since making these adjustments, but I believe it will probably heat up again if I push it hard enough.

I'll check the sensor you mentioned, and will post my results when I've tested it.

Thanks,

Ken

 

Check the water pump, my brothers 01 HO was doing the same thing, it turns out the shaft was turning inside the impeller and it would not pump water.

 

Thanks Aczr2k. That sounds like a good possibility. I'll post my findings when I check it out.
Ken