I replaced that one first. Could I heat the sensor to see if the fan come on, say with a torch?

 

NO torch! not good around gas for you and the atv! Best way to check IF you don't have the sensor installed yet,But if you do,DISCONNECT sensor connector and remove sensor from radiator if you haven't installed coolant back in. Then reconnect sensor and either use a heat gun OR better yet a cup of BOILING water from the microwave and with the key on,drop the sensor in the cup. You will see real quick if the fan comes on!! If fan works,DISCONNECT sensor from the connector and reinstall in radiator with teflon tape or some newer ones have a rubber gasket installed,disconnecting allows the wire to turn freely and won't twist and damage sensor harness when you install it back in the radiator! You say you have checked out the impeller?, then I would button everything up and you can use water if you just want to test first! If the fan comes on and NO gushing from radiator,then drain the water(drain on opposite side of sensor),install antifreeze,leave cap off until the fan kicks on,then top off radiator and overflow bottle.IF water still gushes up,then possibly a radiator problem since you say you have checked the thermostat,impeller, and the sealed fuse. Good luck OPT

 

Man OH man what a chore. I started all over so I really can't say what the actual problem was. Could have been a combination of things. Had some time today and did it all. Removed thermostat, flushed radiator from the bottom up. Checked battery and 14 when running, all good. Fired it up and filled up with water. Let it run for about 15 minutes and low and behold no bubbling and the fan came on. Let run for a little while longer and no overheat light. I guess the thermostat was either not opening all the way or not at correct temp. Either way seems to be OK now. Not a head gasket and I was happy about that. Also bought a new radiator cap, but it releases at 16 lbs not 13, but I don't see too much issue there. Thanks for all the help. Great to have a site where people help each other.
Thank you again
Paul P.

 

Ok,
Received my parts, radiator fan sensor, speedo sensor, front and rear brake pads. Cleaned the radiator that was caked with dirt. Put it altogether today and the fan comes on when hot and then off then again on. Speedo works now. I think I need to blead the back brake, seems spongy.But all in all a good day. Want to go around and greese all fitings and I will be ready to ride next weekend....Oh yaeh check oil level.

 

Congrats to both of you! OPT

 

OK, I'm thinking the final culprit was the thermostat. Prior to the main issue, my fan would come on almost all the time. Now that the new sensor is in and thermostat it comes on much less and stays on less time. Does this make sense? OH yea one complaint. The plastic on these quads is a PITA. Hard to get lined up correctly. Took a while, but good to go. What is the trick to getting the front plastic off? I just got it loose and moved it around. Do you need to take off the pod and handlebars to get it all the way off? Would be nice if they had a split in it somewhere so it could just be slipped out. Just my 2Cents.

 

The pod has to come off,then take the front cab completely loose then turn sideways to where the open area clears over the left side of the handle bars,then slide over to where you can slide over the ride side bar and up and out! You don't have to take the bars off! THAT IS if you want to take the front cab off?? Congrats on getting it fixed,yes fan should cycle on and off with no hot light,sounds like you have it! OPT