I have a 2010 base model (1LT) and my problem is it runs hot when in slow traffic or around town. The temp can climb as high as 220 and then the fans come on but can't seem to cool it down much. Turning off the a/c doesn't seem to help much. But once I get moving and up to speeds of 35 or more, the radiator gets some fresh air flow and it cools right back down to 192. I'm guessing the thermostat is a 192 degree. This is almost a 30 degree temperature swing. Is this normal? Should I switch to a 160 thermostat?