Need Help - I've recently purchased this Quad I took it out and after about an hour it would overheat, I first found that the previous owner used radiotar stop leak. Removed the old radiator, flushed the system, birped the radiator,removed waterpump housing and verified that impeller is in good condition and turns when engine is turned over, replaced radiator cap, replaced all fluids throughout, fan kicks on once up to tempature and at regular intervals or when needed, when it did overheat it overflows to expansion tank. I'm at a loss, please help thanks!

 

When the engine gets hot it is supposed to expand into the overflow tank. What makes you think it is overheating? Is the radiator boiling?

 

Yes the radiator does boil and the check engine HOT displays takes about an hour. Also worth mentioning I pulled out the thermostat to test in boiling water it did open and close, it opened about a 3/8 of an inch.

 

Did you use a thermometer to see at what temp the thermostats opened? When they go bad, they still may open but at a much higher temp...

 

No I didn't thought about it this morning so I decided to order a thermostat. We came to the same conclusion so that is a good sign. I will update once I receive and replace.thanks for your input and knowledge!

 

Update - Replaced the thermostat and no overheating. Thanks again!