[Ed Saniewski]

I agree with Eagle, when you flushed the engine it caused rust and other garbage to loosen up. I recently took a car for a ride that had been sitting for a while and had the same problem. The top hose was boiling hot with steaming water coming out the overflow. The lower water hose and pipe were barely warm.
Remove the top and bottom hoses, Take a flexible radiator hose and connect it to the lower outlet on the radiator. Now take a garden hose and plug it into the hose and seal it up with a rag. Turn on the water and watch all the junk come out the top inlet. Do this for a while and you might save a few bucks getting the radiator flushed at a shop.