After 2003 and on they have no rad temp sensor, its all done by the thermostat I think now.

 

My take on it is it has NOTHING to do with much that you are fooling with as all the sensors are fine, you DID purge out all the air, etc. Its the fan itself...I have an 01 500HO Sportsman, last year during the drought here in ohio it was 100+ degrees, fan was on, etc...but it still overheated. I removed the fan and immediately could tell the bushings were shot in it, bought a new one off Ebay for 20 bucks (9" electric fan I believe) it spun smooth, faster, etc, was easy to install, ya simply remove the radiator side cover panel and a tire from one side, and the fan will slide right out. I was able to remove and reinstall all 4 bolts without removing anything but the lil plastic rad side panels. and your machine is a 02..close enough to my '01...And fluke of all flukes the Ebay fan was a DIRECT bolt in replacement...how sweet is that.

do the fan ! it'll solve your problem.

 

Had the same thing on my 2001. My fan died and the dealer wanted $320 Canadian. I bought one of ebay for $65 new.
I though I may have to rig it abit to work but its turned out to be the exact same "Spal VA07-AP12/C-58A" fan that was on the atv stock!
I felt like calling the cops on the Polaris dealership for attempted theft. LOL

 

YEP...OLD FAN !
Mine would spin...and seemingly fast...but it was half the speed of a new fresh fan...dealer will rip ya good for it too...ebay...the way to go...and it was surprisingly easy...
I was afraid I would have to remove the front rack, winch, radiator, sub assembly, all kinds of crap...but nope, the 2 plastic side panels by the radiator and 1 front tire and 4 lil bolts deep under the rack that hold the fan to the radiator and it slid right out...bench tested them to compare fan speeds...HUGE difference..So it'll still spin, but not move the CFM of air it needs to actually cool.

 

LOL same here.
My goof Clymer manual wanted me to take the front rack,bumper and fenders to change the fan.
I changed it from behind without taking any parts off, not even the wheel and was done in 20 minutes.

My clymer manual wanted me to take the two clutches off to change a starter, all I did was remove the air box from above to get at it.
Do not believe everything you read.

 

No offence sololucky but your advice is so far in left field it is hard to fathom???

The fan runs fine when high-temp sensor in rad is jumpered out.

Right now with the 2002 idling and warmed up and fan jumpered it will not overheat...and the coolant circulates fine.

I did change rad sensor but I am unable to get all the air out of my system.

I jacked up the front end and idled the bike for 30 minutes with fan jumpered and shook the front end.

When I rev the engine up and get some air bubbles so I am assuming that my head gasket is indeed gone. I can only hope that the head is not warped.

I do not have any coolant in my engine oil?

Anyone else have some ideas...?

 

Something you can check if you haven't already is the water pump impeller. If the atv's gotten hot in the past for any reason (trapped air,low coolant,etc) trapped air in the water pump cover can get super hot causing cavitation(just like a water craft impellers),melting impeller fins,causing impellers to loosen on the shaft to where they can't push enough water through the system to get rid of the air.Then they can overheat before the fan kicks on.Plus looking back through your posts I don't see any mention of you checking the impeller. Just a long shot,but worth trying. Plus along with lifting the front end,lift it also on the passenger side way over,then the drivers side and see if you can bleed the air better. We had to do this on some Rangers that had a problem on trapped air. Just fishin' around again... Burning through a bunch of different temp sensors isn't normal.PLUS have you checked the 10 amp fan circuit breaker under the front panel in the sealed pouch?? If it's corroded or shorted out the fan won't kick on... Item #3.http://www.cyclepartswarehouse.com/f...2002&fveh=5582

 

Thanx for all your help OPT, and others that replied as well.

I managed to get it burped and fan is coming on again.

I think I wasn't letting it get hot enough to force the air out, I was paranoid about burning out another rad sensor.

I have a water temp sensor and guage coming that I am going to install as well as manual fan over-ride switch with a indicating light. I am going to wire the switch in parallel with rad sensor. The indication light will show when the fan is running in either automatic(rad sensor controlled) or when I switch to manual over-ride.

I still think I might have a problem in system.

I appear to have good air flow through the rad but plan on giving it a thorough cleaning.

I also suspect either the thermostat is intermittent or water pump impeller blades could be issue as well.

I am still wondering if I have a bad head gasket. I will probably take it to small engine mech I know, he machines heads and installs o-rings and he says they work alot better than gaskets.

For giggles I tested the old sensor in boiling water and it is NFG.

 

On high performance engines, sometimes grooves are machined with metal O-Rings installed to help pinch the gasket around the cylinder and create a better seal. However, with a stock 500 H.O. I would stay away from messing with anything like that when a properly installed head gasket will last for a looong time. Its just more cost and trouble IMO.

 

I was going over bike greasing it and noticed I have3 bad u-joints. I am going to do all 4. Should I also do front diff bearings and seals at same time???

How many miles should you get out of a properly serviced(greased) u-joint?

This bike only has 3500 miles on it?