neon loosing coolant

hi all, need help with diognostics. filled cooling system, pressurized each cylinder 1 .by 1 at top dead center. no bubbles. then i cranked it over putting one spark plug back in, then another ect. its a 4 cylinder. then when i put the last plug back in and cranked it water shot out of the radiator. so i put pressure in that cylinder again on top dead center, and no bubbles in the cooling system. im thinking the head is cracked under the valves so only pressure gets in the cooling system when the valves open. cracked head im guessing, not a head gasket. any help would be great!