I have a 2006 700 Ranger that is over heating. I have replaced the thermostat, antifreeze, and I have burped it four times the last time I had the front end three feet off the ground and ran it for one hour. The fan would come on about every three minutes cool the antifreeze and shut down. Every time it over heats the fan will be running. I can stop and let it idle it will cool down in two or three minutes. I have an inferred thermometer and when it is hot the engine temp. will be around235 and the radiator will be between 190 and 200. So I think the water is circulating. I can only ride about 2 miles before it over heats. I have not been able to find any leaks. Any suggestions?

 

On Rangers when you think you've burped them enough,burp them some more. 6 feet of supply and return hoses along within the engine it's hard to get all the air out. Plus on the 700 and 800 they have a bleed screw on the thermostat housing that can help purge trapped air pockets.Item#7.

 

Raised ranger 3 feet off ground. Ran engine 2 hours with radiator cap off. Bleed thermostat bleeder 5 times. Drove ranger 10 minutes before it overheated. This makes about a total of 5 hours that i have ran the engine without the radiator cap. Do you think it still has air in the lines or can it be something else?

 

You didn't say if the fan is kicking on or not,hopefully it is.That would eliminate the thermister sensor on the side of the head.Top off the radiator and replace the cap and take it for a spin. If it still over heats,pull the thermostat and you can test it in boiling water. Should open when plunged in hot water. If the thermister sensor(for the fan) and thermostat are both operating ok,then I'd check the impeller itself. I've found them spinning on shafts and in some cases melted from heat and cavitation from air trapped in the water pump cavity. Saw that fan is coming on and you have a new thermostat,but even it could be faulty.I'd test it just to eliminate it. Impeller would be the last thing to check as long as you're not loosing coolant from around the head.Plus you may need to pull the floor board and check the joints on the cooling hoses. Plus is radiator getting hot from one side to another and clean especially around the back by the fan? This has caused a lot of over heating problems also.