Freosa head gasket??


Hi Guys.
My 1992 1600cc petrol Ferosa has been fine but recently decided not to play any more. I took the plugs out to check to see if I had good sparks but when I cranked it over it pumped lots of water out of the cylinders. Head gasket gone of course! I stripped it down and the gasket was fine, no crack in the head, nothing wrong with it at all. Only other thing I could think of was the inlet manifold which is pre heated by the coolent but no probs there either.

Anybody got any ideas, please