I have a 2001 sportsman 500 that is overheating. When it first started the fan would not run, replaced the sensor and it was fine. After that it would run over into the overflow bottle but the fan would not be on, so I cleaned the radiator and it seemed fine, then started again. Now so far the temp light has never came on. Last thing I did was remove the t-stat and replace the cap. Now the temp light is coming on after about 1/2 hour, and once the fan comes on it never cools down low enough for the fan to turn off, but it is not overflowing anymore. Any ideas, could this be caused from the back off the radiator being clogged. This is the only thing I have not tried. Sorry for the long post, just need t/s help.

 

Make absolutely sure the radiator fins are clean. Place a trouble light or flash light in front or behind radiator and ch for light being blocked by mud/dirt or debris, clean as needed. If the fan does run and asumeing the fan sender unit is ok; is the fan turning @ the proper rpm?? Does the fan sound normal?? Listen to another sound similar?? If not maybe time for a new fan. The radiator may be plugged internally, not easy to determine and not too likely. The rad hoses not pinched any where, something moved or stick pinced a hose partially shut?? Just some ideas, HTH. bob...................

 

Yes it could be from the back of the rad being plugged!!!!!

It sucks the air in from the front of the quad and blows the warm air back towards the engine!!

The both sides need to be clean!!!

I put a tissue paper on the front screen and it should stay there when the fan is running,This will tell you there is draw from the back of the RAD(fan side) through the fins and to the screen, Just don't leave the paper there!!....LOL...LOL..........Caper............

 

Caper the tissue paper idea is a good one. I usually light a cigeratte in front of it and see if it'll pull the smoke thru but the paper idea is good too!!

 

I don't smoke!!!......LOL.........LOL.........Caper....... .....

I heard it BAD for you!!!!!!...............

 

just try unpluging the sensor it should default to the closed position which means your fan will run even if the bike is cold, could there be oil in your coolant or vice versa Head plugged does water flow through the motor i had to replace my fan because it was not turning fast enough, check your water pump there is 3 seals in there one could be gone not allowing to build pressure