Honda Rubicon "overheating"

[yanmars]

My 2005 Honda Rubicon runs fine when it is cold. When it gets warm it loses power. Sometimes the fan comes on and sometimes not, more often not. I think if the fan operated correctly it would not get warm. The radiator is not clogged, good antifreeze etc. I do not think any hoses collapse, all components are newer.
I have had this checked out more than once by trained Honda personnel. Could I just get a manual switch or have the fan run all the time? Normally no trouble in winter but trouble in the summer. Thanks

 

[SpudHauler]

I would look to having the thermostat replaced.

While the system is open, flush it completely and put new antifreeze.

If the drive belt and CVT system has not been serviced in a long time issues there can cause problems. Mainly worn parts make it act like it starts in second gear and you are always a gear to high. I know it doesn't have gears but each ratio change between pulleys is like a gear and a worn belt can put you in a situation like being in 1 gear too high. Engine works harder all the time and heats up.

Other checks would be to raise four wheeler and make sure all wheels move by hand freely, no sticky brakes.

 

[rmk700]

The fan is not suppose to stay running. Mine only comes on when I'm working it hard. How do you tell it's overheating?

 

[rmk700]

I would look to having the thermostat replaced.

While the system is open, flush it completely and put new antifreeze.

If the drive belt and CVT system has not been serviced in a long time issues there can cause problems. Mainly worn parts make it act like it starts in second gear and you are always a gear to high. I know it doesn't have gears but each ratio change between pulleys is like a gear and a worn belt can put you in a situation like being in 1 gear too high. Engine works harder all the time and heats up.

Other checks would be to raise four wheeler and make sure all wheels move by hand freely, no sticky brakes.

Has no belt, CVT. runs off a hydrostatic trans. Awesome tranny IMO

 

[SpudHauler]

Thought it had that tranny but something I read said CVT. I was wrong for sure.

Your oil and filter changes changes this oil too or is it separate.

Try changing that as well if not.

Sometimes a little routiine maintenance can solve problems.

True, no engine is designed to run fan full time. Fan is backup for extreme heat situations.

Over sized tires hauling big loads at low speeds would be a time the fan should be coming on to help in cooling the engine.

Still think sticky thermo is the most likely.

 

[crazyal]

Do you have one of the hand held infrared temp meters? Harbor Freight sells them pretty cheap. If so I would check a few points to see what the engine is running at. The manual should tell you at what point the fan should come on and it should be easy to locate the sensor so you should be able to tell roughly if the sensor is working correctly.

 

[dusty3030]

Remember the engine oil is the tranny oil too.
Are you running recommended oil?
My Rubicon when it was cold would stall out until it warmed up and the oil thinned.
Also change the plug if you never have with the oe NGK iridium that comes in it.

 

[yanmars]

I use just the Honda oil that they recommend.

 

[dusty3030]

Cool, determine now is it overheating and engine loosing power or is it something else.
I think it will end up being something else. The transmission on these is really a variable displacement pump using the engine oil as the fluid.
I think you are chasing a fix in the wrong direction. Need to make sure the transmission is operating correctly - try it in manual mode and in auto modes 1 and 2 etc and see if there is any difference.

 

[dusty3030]

Also, on looses power, please give us more detail on what that means - ie what running under load, no load, pulling something, going up a hill etc.
Do the engine RPMS drop or does the engine run fine and the machine is unresponsive etc.