After searching the forum and attempting suggested paths to fix my problem, I am still overheating. I checked the radiator, it's clean. I checked all the hoses, no leaks. I've attempted to burp the system, and think I've been successful. The coolant appears to flow, (I can see it flowing down below the radiator cap), so I don't think the water pump is bad. With the radiator cap on, it starts to push water out the overflow tank. The cooling fan appears to be working too, although the last time I was working on it, it didn't come on before it started filling up the overflow tank. Is this a symptom of a defective radiator cap? Please help[img]i/expressions/face-icon-small-confused.gif[/img]

 

Cap maybe!

AT Wyanoka OK. Little Saharra sand dunes, we always see 700 Polaris over heating, pulled a few in!
Possible still a radiator plurge problem.
Anti-freeze mix OK?

 

make sure you check your heat sensor for connection. if the coolant flows visibly, then it's not a water pump problem. when you say overheating, do you mean it just feels really hot, or does a warning light come on? there have been plenty times i've been on the ol raptor and it feels hot as h$ll, but the light never comes on. the fan doesnt kick on usually until it gets really hot. it's like a failsafe. if the coolant cant keep it cool, then the fan kicks on. and if the fan cant keep it cool, the light comes on saying "hey, it's hot as h$ll down here, shut me off"

 

The "Hot" indicator on the LED screen comes on, usually about the same time it starts blowing coolant out the reserve tank. I'm not sure the thing is completly purged. I have followed the instructions in the book, but never feel sure I've got it completly purged. One thing, I don't see coolant flowing back into the filler neck just below the radiator cap until it warms up. Does this engine have a thermostat that would cause what I'm seeing? I appoligize as I'm not real familiar with the innerworkings of this quad. I think the coolant mix is pretty close ~ 50/50 to 60/40...

 

any engine that's liquid cooled is going to have a thermostat. it's pretty cheap to fix and easy, if you know what you're doing. if the thermostat is messed up, it wont allow coolant to flow to cool the engine, causing overheating. there really isnt any way to test it yourself, you just have to replace it and see if it fixes the problem.

 

It does have a thermostat. It should begin opening at 176 degrees F and be fully open at 205 degrees F, so sayeth the sevrice manual.

 

take your radiator guard/mesh screen off and check to see if the radiator is blocked by dried up mud and other stuff. I have read a handfull of posts where guys have talked about finding this sort of blockage in front of the radiator which caused their machines to overheat.

 

Blocked radiator was one of the first things I checked. Is there a web site with some good "How To" instructions for things like thermostat replacement? Thanks.....[img]i/expressions/face-icon-small-blush.gif[/img]

 

No webpages I know of. However, you should be able to go here and look for your year and model and find cylinder and cylinder head to look at a diagram of the unit. It looks like a regular thermostat housing found on most automobile engines and should be connected to a hose going to the radiator.

 

Take the fan shroud off. try to remove or loosen the radiator. I bet the back is gunked up with mud in all four corners of the rear of the radiator. Once i cleaned the radiator real well this way, no overheating problems since. I hosed it down with a citrus degreaser like Orange Blast and kept rinsing. The front may look alright but if you remove the radiator, i'll bet you'll be surprised at how nasty the rear is. Just my 2 cents.