Overheating

I dont know anything about cars, but I had an issue once that lasted 2 years and had the car to numerous and different repair shops. I received a variety of illness diagnosis from each one and of course all were different and after paying lots of money for repairs that didn't work... I finally changed the radiator cap and that fixed the problem. I don't know how or why because I am not mechanically inclined... I just know that was the problem and not one of the shops I took it too cold figure it out.

This is just my opinion but I think you should go in and have it properly flushed your cooling system maintenanced and flashed and put new coolant in and let them replace the thermostat too because that might be giving you problems and then see what happens you know unless you noticed a lot of water in the oil or its milky then I would just try to see what the shop would do for you unless you want to flush it yourself good luck.