Usually you bend connecting rods before you damage the headgasket when hydro locking.
But what have you got to lose pulling the plugs, purging oil from the cylinders and driving the car?? If it still runs, drive it and watch the temps and make sure the CCV does not freeze again.
CCV freeze up is most likely not due to a bad CCV but due to brown mayo/goo in the crankcase because of a bad thermostat and short trips in the cold weather. The brown mayo/goo is a water/oil milkshake mix that will freeze and clog the CCV and CCV oil return line. The CCV oil return line and a clogged dipstick tube are really the most likely cause of this problem along with the crankcase never getting hot enough to "cook" off water vapor in the crankcase.
Last edited by jfoj; 01-26-2013 at 06:30 AM.