only overheats, when i go on long distance trips, around town temp ,stays dead center, like today it ws 98 deg, it went a notch pass dead center, and stayed there off and on. i am thinking i need to change the thermostat, might be stickingat high temp, any ideas.

Might also want to check your water pump and water pump belt tensioner.

Also make sure the surge tank cap holds pressure and the purge line is free flowing.