It never fails, I just can't start my weekend a day early.

I replaced the coolant-weeping original brass radiator in my Dart Sport with a cross-flow dual-core aluminum radiator. I warmed up the car with the radiator cap off, checked for leaks, and waited until the coolant started bubbling. I then added more coolant mix until it was 1.5" below the cap, and still bubbling, then checked for leaks. I then capped it for a few minutes and triple-checked for leaks - it was solid. I thought to myself "time for a test drive" and drove out of the neighborhood.

Well, 1/2 mile away, while going through the first traffic light I heard a little "thunk" sound and then saw steam billowing out from under the hood. Yep, some sort of debris took out 1/4" at the edge of one of the rows about 3" from the top, and coolant began gushing out.

What's the easiest way to repair the radiator myself? I certainly don't want to buy another one, and I'd rather not be without the car for another 2-3 weeks while a shop bends me over repairing what I've got. I haven't been able to enjoy this car during the spring or summer for the last 3 years.

Should I just get some needle-nosed pliers and crimp & twist the offending core? I can't see 14-16psi being enough to burst through that...