Ok, I have a 2003 arctic cat 400, some please explain to me the oil cooling system. the radiator I have, how do I check fluid level ? what fluid do I use in radiator ? In my owners manual it talks a little about the radiator on a 500, but not on a 400. I posted in an earlier post that after running my machine for a while, my legs started to get real hot. and I noticed that my radiator fan was not comming on. so I wired it into my egnition switch so when I turned on the key it would run all the time, ( thinking this would solve my legs getting hot problem, It Did'nt.) so now I am trying to figure out what else it could be.. Is my oil cooling system pluged ? is my fluid just low ? I took the garden hose and washed down the outside of the radiator, that did'nt help... There has to be a reason why, I never had a leg heating problem before this year. another thing my radiator warning light has never come on. Please Help,
Steve

 

My wife rides a 05 400 with the same set up. Simply put, oil from the engine flows through the "radiator" and when the engine gets "hot" the fan kicks on to help cool the oil in the radiator before it re-enters the engine. Those engines typically run warm and it will be noticeable on your legs. We ran for two days at Hatfield/Mccoy this summer when it was 100 degrees and although it was warm we had no problems. Just make sure your oil is at the proper level..

 

Oil cooling is pretty well 100% trouble free. It just makes the oil circulation a longer trip out side the motor before re entering the motor allowing the oil to be cooler then a machine with no oil cooler at all.

Even with no fan on the oil cooler it still does its job by the fact the oil has been re routed from the crankcase through the oil cooler rad before entering the motor again.
My 350 Yamaha had a oil cooler but no fan assist whats so ever.
Air cool Motors really do not have a over heat light but more of a warning light that tells you your oil is low or oil pressure.

My 250 Yamaha Moto4 never even had a oil cooler.

"Wet sump" motors hold there oil in the motor's crankcase and use oil coolers the most.
My 500 has a "Dry sump" motor where the oil is held in a separate outside oil tank away from the motor so the oil tank kinda acts as a oil cooler.

 

Check the color of your spark plug. I have the same machine 03 400i. In the past, when my leg begins to get a little warm the plug is getting darker (towards black from tan) so it is running rich. It is very easy to notice at night when the exhaust glows a cherry red!

I usually replace the plug, check the air jet setting on the carb and as a last result check the valve clearance.

It has alsways gone away. But, it has also always ran a little on the warmer side.

Swampy