My 2002 sportsman 500 HO is making coolant, I drained the coolant reservoir topped the radiator off and ran quad for a bit and coolant filled the reservoir up to the point it was coming out the breather hole in the cap, fan was kicking on and didn't seem like it was over heating but when I bought the quad the fan and temp switch were bypassed. Haven't done any repairs yet to cooling system yet as I just got done with the 4 wheel drive system that's messed up. The rad doesn't look to be plugged but plan on removing it anyways and clean it out. Any help would be great.

 

Get a new radiator sensor and hook it up right. Raise the front end,fill the radiator and leave the radiator cap off, let the fan cycle on and off several times. Add coolant to the radiator as it goes down when the fan kicks on. May take a while on doing this to remove all trapped air pockets. Squeezing the hoses may help also. Good idea on cleaning the radiator as they can really get clogged up especially behind the fan. One of the reasons they're so hard to bleed is that the coolant return line goes to the filler neck instead of back to the radiator.They finally changed that on the 2004 model and bleeding was a little easier.

 

I have already wired it back up and will order a new rad sensor, should I replace the T-Stat due to being the original thermostat?

 

You can test if it opens correctly by dropping it in boiling water. If in doubt replace it.