I have a weird problem. I recently changed the radiator and flushed the whole coolant system during replacing the radiator. I also flushed the heating core by itself. The thermostat was recently changed and it doesn't seems to be stuck open because if the car is sitting it warms up properly. The coolant temperature sensor was also changed recently because the temperature gauge would start in the middle and that seemed to be the solution to that problem.
The problem: When I start the car and leave it sitting, it warms up properly and stay at 1/2 of the temperature gauge. However when I start driving the temperature gauge drops a lot. Most of my commute is on the highway and most of the time the temperature gauge stays at 1/8. This mainly affects the heat, right now if I leave the car sitting the heat works great but once I start driving on the highway it is not as hot.
I talked to an employee at Autozone and he told me to make sure I burped the engine. From what I am reading online the car would be over heating if it was not properly burped. But it can't hurt to try, so I plan on getting a lisle funnel soon.
Any other solutions or ideas of what the problem might be?