Clapton,
one more thing. I did notice my coolant tank cap was loose and not tightly screwed on.
And it was a while ago since I checked my coolant so the cap may have been loose for a long while. I'm now wondering if the system had a lack of pressure and created some sort of puddling along the pipes.
Does this make sense? I'm trying to rationalize how the failure happened so I can describe it to the mechanic today.
Thanks again.