[Rick Parker]

Karl:
If it not mounted a bit of heat applied (propane torch or careful use with oxy/acetalyne on the underside of the manifold around the circumfrence of the tube should release the grip of the interference fit. If you want to save the tube use a "strap type grip wrench" outside to avoid marring the tube and use a socket inside to prevent the wall from collapsing. It should twist out and then use cup plug to fill the hole.

................Rick