Water disappering from engine

That would suggest a head gasket leak. Check the oil level to see if it's going up. In the rare event it is, have it looked at right away. Antifreeze will dissolve the soft outer layer of engine bearings. More likely you'll see white smoke from the tail pipe. You can also add a small bottle of dye to the coolant, then after driving for a few miles, search with a black light. The dye will show up as a bright yellow stain.