I have search and could not find any answer.

My top radiator hose the curve one or S, for some reason the end that goes to the engine is inflating like a balloon is there a back pressure or something that causes this, I am afraid that while I am driving it explode or tear that it will leave me hanging in the middle of the freeway.

I just replace the hose and lets see tomorrow after I did a 50 miles and see what happens.

What do you think is causing this?

 

First of all, your engine type info would be useful. Just put it in your sig

How much deflection are we talking? a quarter inch? an inch?? literally "balloon" size?

Your cooling system by design is under pressure when the engine is hot, this raises the boiling point of the coolent. Therefore you will notice your hoses become "taught" and expand most noticably around the clamps such as where you are talking about. They will not however expand much at all unless the hose is old and the rubber deteriorated. Replacing it will alleviate the problem if thats the case.

Go ahead and replace your radiator cap incase its gone bad and somehow over pressurizing your cooling system...

sohc