I'm sorry about this happening to you...it sucks when were faced with a lot of labor to check for an engine failure. Less work then pulling the head, if you could get the prechambers out and snake in a scope (borrow one or buy a used Snapon on ebay, great to have in any event, about $3-500 used), you would see water drops on the piston or residue on the cylinder walls, even some rust if a head gasket was leaking coolant in there. Like others said, pulling the head is the only way to be sure if there is a crack or it was just a gasket. But the scope test helped me realize when my engine was toast.