If im not mistaken. Hydrolocking is when the cyliders are filled with water and when u try to start the car nothing turns..... Wouldnt u just remove all the spark plugs and turn the engine? Wouldnt that spray all the water out the chamber? Then when u put the plugs back on. Start the engine and then the remaining water will evaporate or exit through the exhaust valve. In the aviation industry. When a plane engine hydrolocks (cause of oil) thats what they do to drain the oil from the cylinders. I might be wrong but thats my insight. Anyone have a different opinion?