Before I Posted, I did a search, and found lots of articles to pull info from, I just want to make sure before I take it in to the dealer, I have covered every basis.

Info: The last 2 times I rode my Rubicon, I had problems overheating on the trails. It is not brand new, it is a year old (300 miles 60 hours), and this is the first time I have had an over-temp without it being 109deg outside (that was last summer and after it happened I changed the oil). The first time this year was at the deer lease in Louisiana, lots of dust, I chalked it up to gunk in the radiator I couldn't get out.

Today, I was riding on the trails by the house with my wife and I got the over-temp again, on easy trails, no high-speeds, no mud.

Here is what I did: Checked the reservoir, it was at the LOW line, so I added some distilled water, not much, just enough to put it between the lines. Also I sprayed the radiator a bit to clean it. This was mid ride, light came back on.

So I let it cool, checked the radiator itself, full, squeezed the hoses going into the radiator to check for air, maybe it bubbled, couldn't tell. Tried to remove the screen in front of my radiator and cleaned more dirt out of it. Got a lot off of it, apparently I need to do a better job cleaning.

So Im going riding tomorrow, I will see if the light comes back on. Is there anything else I missed???

If the radiator is getting hot, that means the pump works right? Its pulling heat from the engine? If I get problems tomorrow unless you guys can tell me I missed something, I think I will take it in.

Thanks in advance
Spirit

 

Are you rinsing the dirt out of the radiator?? Rinsing it opposite of air flow?Is the thermastat opening??

 

I would guess the gunked up radiator was your problem. It doesn't take much of a coating of mud or chaffe to drastically reduce its cooling.

I forget how the Rubicon is set up, but I think there are side shrouds on either side of the radiator that you can remove, and then reach in and spray out from behind.

Also check the oil level. Being a dry sump, to get an accurate reading the machine needs to idle around 4 minutes with no throttle, then sit for a couple minutes.

If it continues to overheat and the radiator is absolutely positively clean, then I'd start to suspect the thermostat.

 

These have a reputation for running hot. Any torque converter trans creates a lot of heat.

Add some Redline Water Wetter to the coolant. Actually, the most efficient coolant is just plain old water. Doubt you need antifreeze in Louisiana, so maybe drain the coolant and replace it with plain water + Water Wetter. Water Wetter has anti-corrosion additives, so that isn't an issue.

 

The rubicon doesn't have a torque converter. It uses a centrifugal clutch pretty similar to that found on the geared transmission hondas, and a hydrostat drive...

 

Is the cooling fan coming on?? Can you hear it?

Antifreeze/coolant and water mixed 50/50 will cool alot better than plain water and antifreeze/coolant will absort and transfer more heat than just plain water will.

I would spray water through the radiator fins from the engine side or oposite of the air flow.

 

Dont use plain water as it has a much lower boiling point then antifreeze and will evaporate very quickly from the overflow tank. You will need a 50/50 mix like said before.

 

In a hurry I read Rincon (which IS famous for running hot) instead of Rubicon.

Do some research on the water vs coolant thing. I think you will find some info that is different from the advice given above. I live in the very hot southwest desert, so I know this all first hand!

http://www.redlineoil.com/products_coolant.asp

 

Your link says water with Water Wetter is better than just plain water, I think we all agree with that. I did not see where it states that plain water cools better than a 50/50 mix of water and antifreeze/coolant.

Yes Water Wetter improves the cooling ability of plain water as does ethylene and propylene glycols by increasing the thermal capacity of plain water.

A 50/50 mix of antifreeze/coolant will cool better than just PLAIN water.

Water with Water Wetter added will cool better than plain water also.

The last thing you want in any cooling system is plain old water.

 

The fan is running, forgot to mention in the original post, I make sure when I shut down the bike that I use the kill switch and not the key, turns the engine off but leaves the fan running.

well I haven't sprayed the radiator from the back (engine) side, I have been coming in from the front. I will see if I can get behind it to spray it.

I think I will flush the radiator, and use a mix of distilled water and water wetter. I don't think its a thermostat, I think the engine really is getting too hot.

I will know later today, loading up and leaving in the next hour.

Thanks for the info folks.