I was in Moab a few days ago and did the chicken's corner trail. It wasn't to difficult, but I was going pretty slow most of the time. Being that I was 1000 miles from home, by myself and the trails are pretty rocky I wanted to take it easy. Because there was a ton of RZR UTV kicking up dust when passing me, I had my windows shut most of the time and the a/c on.

About 4 hours into riding I notice my temp gauge was starting to rise. I immediately shut off the A/C and the temp started to lower from 3/4 to about half. Normally it sits right below half and usually never moves after its warmed up. I pulled over and turned off the engine to see if there was anything going on under the hood and there was.... Coolant was bubbling in the reservoir, but not enough for it to spit out. I checked my temp gauge and it was right below half. I waited about 10 minutes to see if it would stop bubbling, but it didn't. So I started the engine to see if the bubbling would stop and it did. I was able to finish the trail without it getting hot again and still drove it around moab, arches and made it back to Portland today without any issues.

Throughout the trip on the trail I was getting whiffs of coolant smells, but I didn't really think it was that big of a deal. I probably lose less then a cup of coolant.

I use to drive this s-10 truck at my old job and when it was really hot out and using the the a/c I would hear the clutch fan getting louder. Isn't the clutch fan suppose to engage more when it gets hot in the engine bay? Because I sure didn't hear it getting louder on my 4runner. Is it possible I have a bad radiator cap?

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