OK, the head is good if it's been checked
like that, I say go back to the intake manifold
gasket, It's sucking coolant or water thru from
the inside, I've seen this happen before, and
that's the only place it could be getting the
coolant from, unless the head gasket is on wrong
Back to that again

, BUT your cam didn't seize
in the head, so it's probably right
Good Luck, keep us posted
Wild