vanishing coolant!!

[strictlypersonl]

I've seen this happen when there's a crack between a cylinder head water passage and the exhaust port too. It only leaked when the engine was hot and the coolant was pressurized. The stuff wasn't visible in the hot exhaust.

[Tinker51]

I had this exact problem in my early Mustang. I looked for years and never found any evidence. The oil was always good, the plugs never showed any strange deposits, the heater core and hoses were always dry as a bone. I put a catch can on the overflow to see if it was blown overboard, it wasn't. Finally, mostly due to unknown age, I took the radiator that showed no signs of leaks out to have it re-cored and overhauled. I asked the guy at the radiator shop if he would test it before opening it up. He put it the water tank and put a few PSI of air in it. I swear it looked like the Lawrence Welk show there were so many bubbles coming from everywhere. I looked at this thing all the time with the car at temperature and running and never saw any evidence but that radiator had more holes then the border between Mexico and the US.