Think I found the root issue last night. After looking around all over OK and north TX for a good HE radiator a local shop was able to get one (Osborn Radiator in South OKC, guy is great). Figured I'd fire it up and see if there were any cold spots on the old one, let it get up to temp with the fan removed and ~190 or so a couple pinholes opened up right behind where the top of the fan would be. Guess since it only did this at temp and right behind the fan it just blew the fluid into vapor. I'd had that fan off at least 3 times and never saw this leak. I'm no expert but I'd never heard of one doing this, only leaking at higher temp then only overheating on the highway.
