First thing we have to know is how hot is it??? What kind of gauge do you have on it? Are the hoses hard to squeeze after just a few minutes or when it's at operating temp? How old is the radiator? Is it the old clogged original or is it new?
Sorry if I didn't see any of this information listed but we need ALL the facts to make a correct diagnosis instead of just spit-balling possible causes.Over heating to me is 230 degrees without coming down
Gus