I took a closer look at the neck last night. I have no idea how it happened, but it is beat to hell. Something must have fallen directly on the cap at some point when the hood was up.
I beat it around a little bit and got the leak down to just a pin prick. Only a couple drops of coolant drip out after a pretty good amount of time. But at this point a couple drops is way too much. If I never see another drop of coolant leak from this thing it will be too soon. I'm sooo done with the cooling system.
Ordered another radiator. Should be on next weekend.
Thanks to all for the help!