Greetings, am new to the forum. Got my first pontoon, an Outback 8 footer, off Craigslist. Used it a lake last weekend, worked fine, no leaks, then put it in back of my truck with half sticking out past the entrance, other half under the camper shell, but in the sun, while I float-tubed another lake for a bit. About an hour and a half later, I got back to the truck and one pontoon was half deflated, other side was really tight and in fact the area of the bladder right around the valve was protruding a bit, but it had not deflated any. I figured I had burst the one bladder by leaving it partially in the sun. But I got it home, took the bladder out, inflated, ran soapy water over everything and can't find any leaks! Anybody know what happened? I figured maybe there was some sort of safety let off with the valve or something, but can't find any info to suggest that. These are the same plastic valves I have on my FishCat 4 float tube. Thanks for any insights.