Overheating 101

Just went thru the postings on the Chev overheating below, and can sympathise with the aggrravation, having gone thru exactly the same thing myself, 'cuz I forgot Overheating 101: make sure the coolant is really that hot!! Now I know a couple more or less giveaways stood out: no really hot heat from the heater, and little excess pressure when the cap removed, but regardless, unless it actually boils , stick a thermomeeter in it to see the real temp. And as to the leaking headgasket, that was a valid guess; I have one doing that right now, with not a drop of oil in the coolant or coolant in the oil. (I'm the voice of sadder (and poorer) but wiser experience.