I am loosing coolant in my 93 3.8, yesterday i noticed that overflow was empty so i filled it to the cold line. When i got up this morning the tank was almost empty again, so i filled it up. I looked for a leak but could not find one. Could this be the head gasket? It was replaced by the previous owner just before i got it, which is about a year ago. There is no white smoke or rough idle, and the oil level is fine and it isnt milky. Any help is appreciated.