Well, I had a few hours yesterday, and I finally changed out the Radiator in the 03 Chevy Express. Got one for $100, had it pressure tested, and got it changed in about 2 hours, with a little fiddle f&^%$ing around with other things. Only expense was more coolant, and an $8 nut (dealer part) with a clip for the tranny cooler lines. Got a pack of QD clips at the parts store, but they didn't lock in well ($10 for an "assorted" package....you can't buy just one).
These radiators are plastic/metal, and can't really be repaired.
I'm feeling good about me Chevy now.
Only other problem is "chest pain" from leaning over the front radiator support....uncomfortable. And as short as I am, I had to stand on a milk crate.