2006 AC 500 automatic with a Suzuki motor. It is overheating and blowing the coolant out the radiator overflow.
This happened on a trail. The over temp light came on. Let the engine cool off. Put more water in radator and made it a back.
With it back home we put more water in it and started it. It seems like the top of the radiator was hot and bottom was not hot. The top radiator hose was hot bottom just a little warm. It stayed like this until it started to start blowing water out the overflow.
We thought it was a stuck thermostat. So we pulled out the thermostat and tried it again. Same thing top hose hot and bottom one not. Got hot and started blowing out the overflow.
So bad water pump or plugged radiator? Any suggestion as to what to try next.

 

Ok did a little work on it today. The radiator does not seemed to be blocked internally. I disconnected the hose from the water pump and the radiator will drain. Put more water in radiator and it would come out lower hose.
I pulled off the cover to the water pump. The impeller looks good. It turns when I pull the pull start.
Then I connected a garden hose to the hose from the water pump to the engine. Water would go through the engine and radiator and come out the other hose for the water pump. There is a lot of restrictions in the return water but I would guess that is normal trying to run water thought at the small passages.
Any other ideas before I bring it in to the shop?

 

Might check your thermostat. Take it out, run the quad for a while, and see if it gets hot. If everything else is OK but the thermostat is bad, then it should run too cool.

Thermostats have been known to go bad after an overheating. And, no, I don't know where they put the thermostat on a 500.

 

John, Thermostat was our first thought too. So we already pulled it out. Still same problem.

 

Take a good look at the rad see if the fins are good and not bent, if they are try to straighten with a small piece of thin steel. Also a pluged up rad with dirt mud etc will do this.

 

Status update. I got it working. Now both top and bottom radiator hoses are hot. I think there was air trapped in the system
Now the fan does not kick on. I bet this was the original problem.

So now temp sensor or bad fan? They could make it a little harder to get to. Stupid place for the winch it blocks about half the radiator.

 

check your fan fuse. if you've been in water/mud holes when the fan was on then it will blow the fuse when the fan hits the water due to too much resistance. This is the 1st thing i would have checked as its a simple fix and has happened to my 500 and my 700. Also, if you've been in the mud take a stick or something and turn the fan with it, with out the bike on of course. Mine had gotten mud and dried in the fan and kept it from turning on which blew the fuse. fuse should be under the seat,i think.

 

Fan fuse is good. That was one of the first things we checked too.

 

Did you pull the fan electrical comnnector off and connect it directly to the battery to see if it's the fan or the temperature sensor?

 

Nope that is my next step. BUT I can not reach the connector so I have to pull stoff off to get to it.
I was just hoping for an answer like "the sensor burn out all the time" or "the fans fail all the time."
Then I could order one before I have to pull everything apart.