I seem to be building a lot of pressure in the cooling system. I have replaced all the hoses, the heater core, thermostat, radiator and fan clutch and the radiator cap. I tried to replace everything that I thought might be allowing or causing the coolant to blow into my overflow bottle within a few miles of driving and then after filling that up, it goes out the tube. I have tried to make sure that there is no or as little air in the system as possible. I am not getting any water in my oil, so I was wondering if anyone out there has had a head gasket leak in such a way as to blow from the compression of a piston or two and push it out of the cooling system. I am not finding any coolant on the floor. I seem to be getting pretty good circulation from the water pump too, and it is not leaking, but is not new, but not real old either. Any suggestions or ideas would be helpful.