thermostat was my first thought but i didnt think it would be the cause since the car is at 100 when going 75mph down the highway for an hour on flat ground.

short of going and getting an infrared thermometer, is there a way for me to verify my coolant temps to rule out the gauge being incorrect?


and what about the issue where the temp also climbs while sitting still? my fan clutch seems to be working just fine, so i think we can rule that out.