wow, with that much water coming out the exhaust if there is no water in the oil now there soon will be, no matter what the cause or where its at bull the head and find it befor you get the chocolate colored oil all thru the engine and oil passages, that is a real pain to get out of the engine, with that much water i dont think its a head gasket leaking, its a crack in the engine some where, or maybe just in the head, letting the water drain into a cylinder, find and fix it befor you hydralic lock a cylinder and bend a rod