Originally Posted by Douglas.Sherida

I also have a very hard time imagining how the water pump impeller could be worn down. But with the amount of pitting and scale I found on the thermostat housing (around the hoses), I can't rule it out. But the t-stat housing is aluminum and the water pump is iron, it still seems unlikely. The only way I'll for sure is to pull it.

Besides, at this point, insufficient coolant flow seems to be the most likely explanation to me.

I think I actually created a hole in the radiator, or unplugged one to be exact. I'm certain that this hole in the radiator has nothing to do with the car running hot.