Overheating issues

This is just out there as a shot.
I had a waterpump that the blades were stripped from the shaft.
Externally all looked fine but the blades didn't turn at the same speed as the engine causing the overheating.
I ended up buying the car because no one could figure it out. Look in the rad with cap off and you would see the coolant moving.
Put the cap back on and temps would rise and over heat before you got 2 blocks.
This is just a guess.