94 civic dx
a couple of days ago i opened up my overflow tank to find that it was empty. so i filled it up with some water...to about halfway between min and max. a day ago... it's down to the min mark. both times have been in the morning before the car ever went for a drive. the radiator...still seems full. my car's not overheating. but it seems that my car still smokes white smoke (not a lot) but it still slightly smokes after the car warms up---BUT this is mainly when it's cold at night. but yeah. what could be happening? there's no oil in the coolant...