DIY Aluminum Radiator Repair

Yes. I repaired an aluminum radiator by pouring 2 ton strength clear epoxy into the cooling fins to make about a 1" square around a small hole or crack. I don't remember, but I probably poured it in from both sides. It never leaked again.
I bought a new 1986 Trans Am that my wife drove. The front opening for the radiator was underneath the nose with a little chin spoiler, maybe 2" wide, at the back edge of the opening. One day when she met me for lunch, I noticed that spoiler was missing screws and was dangling in the center. I took it off until I could get more screws. Big mistake. It had electric fans for the radiator so I never expected any problems. Later that day the top radiator hose exploded. It would cool sitting still, but without the spoiler, it would not cool at speed. Replaced the hose but now the aluminum radiator was leaking near the center. A new aluminum radiator was something like $400 in 1986. Radiator shop said it could not be repaired so I figured I couldn't lose anything by trying.