Before I get into my question, first a little background. I have a 05 Rancher AT. Last weekend I rejetted my carb for the higher altitude that I live in but have not adjusted the A/F mixture (yet). Before I jetted I never, ever, heard my fan come on. The day after I jetted, I was riding around a very low speeds, which I have never done before and the fan came on. My ATV (at that time) was at about 95 miles. Today I went for probably the longest ride my ATV has ever been on. It was a very mountainous terrain. Steep up hill and down hill trails. My fan ran practically the whole time and the average speed was about 10-15 mph. I also turned 100 miles on the bike while riding up the trail. The overheat light never came on but I did stop when we got to the top of the mountain and turned off the engine for about 30 minutes to let it cool. I checked my oil level and it was pretty low. As I came down the mountain, I noticed that my change oil light was on (don't know when it actually came on) and my fan ran the whole time. I tried going down the mountain at higher speeds thinking that the air would cool it down. It didn't. When I got back to the truck, I checked the oil again and the oil level was just "barely" registering on the oil "dip stick". Was my ATV running hot because of the lack of oil I had? Did I hurt my engine for running it with low oil? Is it okay for the fan to run for so long? Anythoughts would be greatly appreciated. Thanks!