Are you SURE it's coming from the bottle? I had the hose from the radiator to the bottle rub enough to put a hole in the hose right by the bottle. You just may the same problem??

 

Yeah, it was coming from the bottle. There is a little hole in the top of the over flow cap...was shooting out under quite a bit of pressure. Ended up replacing the thermo sensor/fan switch. Have not been able to get to over heat now...fingers crossed!!