So I thought everything was fine. I drove the car with no overheating issues all day, then tonight after a 10 mile drive the guage indicated I was almost to the point it could not go much higher. It was strange because the guage at one point would drop very steadily like it wasn't reading it correctly. I have never seen the guage drop that quick and it doesnt seem like the car is running that hot.

I did replace the thermostat but from my understanding there is also another one for the guage reading in the car. Where is this located and would it be worth replacing this first before I bring it in somewhere? The fans are kicking on just fine and coolant is flowing through. Thank you.