My ten year old Altima has blown off the main hose to the radiator three times in the past six months. By that I mean the hose disconnects itself from the radiator. The hose is not that old and seems in good condition. After waiting for the car to cool off, I re-attach it and tighten the screw that keeps it tight around the radiator connection. A couple of days ago it separated for the third time. My question is, is there some kind of pressure build up inside the engine causing this? I recently replaced the radiator cap which showed signs of wear and had a feeling the new tight seal was going to cause more pressure and the hose to separate, I was right, it did. I've had a lot of cars over my lifetime and never experienced this situation. Appreciate some help since I'm handy with tools and too poor to afford a mechanic right now.