New LS1 Owners - Newbie Tech - need help with coolant problem

so my car was running hot for a couple days and i figured out that the driver side fan came off the motor so i put that back on and now the fans work. but last night my temp went way past 210 like half way between 210 and the red but as soon as i started going it went back down, keep in mind this is my dash gauge, my gauge pod temp gauge only went to 190. i mean i know that the dash gauges suck but i dont think that its that far off also it could be because the gauge pod one takes its reading from the TB coolant line? no it doesnt have a 160 thermo yet im going to try and get one today but thats beside the problem, the coolant is full the fans are working great but its still overheating when im sitting still and its december. could it be air in the system? whats the best way to make sure that all the air is out? or does anyone have any other suggestions?

Probably just a little bit of Heat Soak from sitting still..once you get moving the air flowing through the Radiator does help too..

yea but its never gotten that hot before especially here in florida when it gets over 100 ive never seen it do that and now its december lol im thinking the 160 thermo will solve the problem hopefully

I borrowed a buddies infared temp gun and shot the CTS and it was within 2-3* of the dash gauge when mine was running a little hot. Is your CTS good? heard your water boiling? Losing coolant? if you've been driving around you have purged the air. That only takes a few minutes. Maybe get hold of a techII or snapon scan tool to verify actual temps.

thermostat? or just a v8 sitting there