I did all that, made even a home made smoke machine. I was thinking it could also be the intake manifold. By putting pressure on it I could have pressed a bad gasket. We will see when I do the head gasket in the coming weeks and change all the gaskets and seals.

__________________
1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).