2005 chevy uplander has new parts but why is it still overheating?

The engine is cold when I first start it up. It never gets hot. Know steam or anything. The needle will go a notch pass the normal range towards the cold side. Then go back to normal. Sometimes it goes down a notch from Hot. The engine runs harder but know steam or bubbling. Then it goes back to normal. Sometimes it will go a few notches from hot then go back to normal. I wish I could show you a pic or video I just took.

That would be helpful. If you upload it anywhere and send me a link I'll watch it.

https://drive.google.com/file/d/1FdigiBNBndBLinNfBhfluE8Hi7OmkdPo/view?usp=drivesdk

Perfect. The first thing I would do is test the coolant temperature sensor, and get an infrared thermometer and point it at the thermostat housing to see if there is even a change in temperature. As smoothly as it is running, it seems the sensor may have gone bad. Watch it like a hawk if you absolutely have to drive it.

Ok great. Thank you so much. Ill let you know how that goes.