Hello i have a 2004.5 sp 500 and the thing practically overheats every ride sometimes right of the bat some times 6hours into beating the $hit out of it. I thought i fixed the problem cause i noticed the rad was low and the thing wasnt bled right once i bled it right it was ok for a while, then it overheats and the light dont just come on the rad boils over into the little coolant jug and its a big show of steam and antifreeze leaving me stranded till i can fill the rad again, last time i said screw it and filled it with crick water to get home but this is not the problem as i did it the last time lol. What could the problem be? also i have recently aquired another problem, my atv sputters off idle like the low rpm jet is plugged once past idle it runs good and it idles fine. this problem slowly started to happen now its stuck like that sept when i first start it up. some times its so bad that it wont even let the engine climb to a higher rpm to get rid of the problem and im stuck with a idling sputtering sportsman.

 

did you ever check the back of the RAD!!!! Where the fan is.....They plug from the rear and the fan usually just keeps running!!!...Caper......Best way to clean the back of the rad is to remove the front storage rack!!!!.....Hope that helps!!!!

 

no i cleaned it. i took all the shrowding off and cleaned the rad right down till it was like the day i bought it. thats whats really confusing, it just over heats whenever it feels like. ive owed a 97 sp and a 2001 and never once had this sorta overheating problem so unless 04.5's are diff (which visually they are not) sept they have a different front bumper design.) The machine does have some pretty intense shielding over the rad. i have some bars going horizontally accross the front grill, but no mud gets caked in them and the machine gets hot even when i dont plunge into the deep mud just simply beatin the **** out of it in 40degree weather on trails. but nothing more then ive ever done on my other two sp's. my question is can there be anything wrong with this machines cooling system? 1) the waterpump must work most of the time if its even possible for it to stop working sometimes cause it may not over heat till after 6hours of riding. 2) what about the thermostat? where is it? 3) could the inside of the rad be plugged some how??

 

Feel if the upper rad hose is HOT not just warm. If it's not hot try a T-stat.

 

are you sure you got all the air out? how long did you run this when it was hot, you could easly warp the head if you drove this for a period of time w/ it over heating. first thing is to make sure the rad. is clean, front and back(sounds like you did)so that you can see thru it with a light. then if so, before you put the antifreeze back in try running a garden hose thru it to make sure inside isnt plugged. like scrammy said check to see if the therostat is good(which i think will be if you can ride 6 hrs) by testing it in a hot pan of water to see if it opens. make sure you have a60/40 or at least a 50/50 mix of coolant.

 

ive only drivin it untill the heat light comes on. this has happened about 3, 4 times is that really bad? i am quite sure that i got all of the air out, can air become a problem after 6 hours of riding? where is the thermostat located?

 

If you can ride for 6 hours one time, but only a few minutes another time, I would probably say the T-stat might be sticking. To make sure you have all the air out of it, get the front end up high (On blocks or hang it from the winch) and run it with the cap off. Get it hot for a while, put the cap on and let it cool. Make sure your resivior is full. When it cools, it should draw coolant from the res into the system and purge air. The T-stat is on the left side of the head. Follow the upper rad hose from the rad to the engine. It should go into the side of the engine. When the HOT light comes on, feel this hose (BE CAREFULL!!!!!!!!) If it's cool, or not scalding your hand, it will probably be a stuck t-stat.

 

scammys right on checking the hose(it should be extremly hot so it would burn) and if its not then the thero is junk. however i have found that people have tried the raising the front end and it diidnt work for them but they were relocating the rad. at the time. i always fill it and then w/ the rad. cap on the first notch(so it doesnt build pressure) let it run this way for a while so the fan cycles on and off a few times and then when its done replace the cao in the full closed position andwhen it does cool it should draw fluid back in the res. tank. this is just how ive found it to work real good.

 

i have a "spare" 1997 sportman 500 motor lieing around would that have the same thermostat? or would the none ho motors have a different one?

 

Scramman, did you have the radiator cap tested. I think the cap should hold back about 14 psi. A friend of mine had a 2002 Sportsman with the same problem you are having, he tried everything and found the cap was venting at about 2 psi. The boiling point of any liquid is based on the pressure. The higher the pressure the higher the boiling point. A new cap is cheap.