It's possible that the cooling system was not properly vented when coolant was replaced which causes an air bubble to get trapped inside the cooling system. That's usually the cause. Wait till vehicle cools, remove raid cap turn on engine let sit approx 1/2 hr. keeping ur eye on it making sure fluid stays at normal weather. Give it a try.
There might be a problem with the radiator. The pipes leading to it might be having some blockage thus water cannot be easily supplied to the radiator that cools the engine. I would recommend you get this checked as soon as possible.