This afternoon driving to work I was stuck in stop and go traffic due to an accident. The temp gauge had been working fine as usaul making it's normal swings when the temp got to around 180-190. With the ac on and stoped the temp rose to 190-195, and seemed to want to keep going. I turned off ac and temp stayed up there until I got going again. I changed the antifreeze last week and put in how much I took out. I know it was hot but truck has never run hot like that before. Should I change t-stat ? Or not worry about it. ? I realize I had more to go until the boiling point just concerned, Thanks for the replies, Brian