My 2007 Silverado has this condition, does anyone know what the problem could be. Dealership said there are no codes stored, could have been the thermostat sticking. Replaced thermostat problem still there. Everything seem to run normal temp gauge falls to 160 or 0. After truck cools down temp gauge returns to working and go to 180- 190. Any help would be great

How hot is the truck running normally with the A/C off? How about with it on?

They will do this when they are overheating to try and save the engine.

What circumstances are you encountering it under?

Verify with a decent scanner that can see live data.

Started truck after setting 3 days engine completely cold. Got the same message, normal temp is around 180 0r 190 never higher. About 200 when towing trailer, as far as circumstances usually after about20 minutes of driving.

Gauge problem?

Like Mike said, drive with scanner connected and see if CTS data matches gauge data....

when the problem is occurring use a temp gun and see if it is in fact running hot. It could be an issue with the electrical side of the system (sensor,wiring,or pcm) and not a mechanical issue. Best to you

Sounds like a bad temperature sensor to me. I suggest you check the actual temperature of the upper radiator hose when this condition starts. If the temperature is reasonable then replace the temperature sensor. You could test it first, but at this age you may as well rule it out today and for the next few years.