In 1980, I bought my first truck, from my Dad, a 1978 Toyota Hilux, at 17 years old. I went through it with fine toothed comb. Replaced points, adjusted the carb, new plugs and plug wires, distributer, adjusted the valves, cleaned the top of the head since I had the valve cover off, etc, etc. Stupid stuff.
My Dad asked "What are you doing to that truck, it's only 2 years old?"
I said, "It's mine now, Pops, and it's going to be perfect!".
Dad shook his head and walked away, muttering... "Don't fix what isn't broken ".
I ruined the distributer messing with the points. Ruined a few other items and spent days and money getting it right again. But, I learned a lot about cars and engines. A lot. And... I learned...Don't fix what isn't broken.
Catch my drift?
It's not overheating, leave it alone.