The only way I know to positively know what the t-stat is operating at is to take the upper hose off and watch the t-stat open and close while measuring the temp of the water coming out. I usually do this when flushing the system. After you know what the t-stat is cycling at then look at the gauge to see what it is reading.
IR thermometers will run a few degrees cooler that actual coolant temp.
IR thermometers will run a few degrees cooler that actual coolant temp.
