why does my punto blow clouds of steam out the exhaust?

my wife recently bought herself a 1995 1100cc fiat punto, once home we discovered that once the engine was warm it started to blow plumes of steam from the exhaust. We have replaced the head-gasket, (head skimmed and tested) replaced the inlet manifold, had it compression tested and emission tested and all is OK. There is no water in the cat or exhaust and does not appear to be using any coolent yet still as the engine warms it starts to blow steam, HELP PLEASE!!!!! is there a known problem or sensor that needs replacing

kevin
February 2009