Ok dude think of it thisaway!!! The compression has more POWER than the coolant pressure.. If you have a headgasket leak into the engine the compression goes OUT INTO the coolant and you get spewing all over the place! FORGET about a headgasket failure!!
If you are loseing coolant it is trickeling down the outside of the engine..SOMEWHERE! Crawl under it with a light and look VERY closely for ONE drop of coolant.. You do not have to have a puddle under it. Perhaps it is only dripping a bit while the pressure is high? Perhaps it is a leak HIGH on the radiator and only drips while the coolant is waaaay up there? You MUST look for the leak with your EYES.
As for how it is running, TUNE it up and see what happens.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />