I might sound really thick but I'm clutching at straws before i venture into changing my head gasket. My car over heated and I lost water from the expansion tank and above the inlet manifold. Does it sound like the head gasket?

 

check the oil, has it got mayo in it (white sludge).....also check your header tank, does that have oil in it?

if not i doubt its HG....does it leak when parked up?
you sure you didnt just split a hose or summat?

 

had the same problem on mine deffo hg