Radiator Hose is Swelling up-???

So I hear no boiling over sounds,,and I dont show a high temp indication on my gauges,,
But damn it,,I drive it a few miles,,,came home,,popped the hood for an oil change out,,and noticed that the uper radiator hose (the one that has the PS cooler in it) was swelling around where the clamp goes,,
I was able to open my radiator cap and it did not explode h20 out,,just some pressure release happened,,,

So what might cause this,,
The hose just being old,,which it has no signs of that (no cracks or bad color),,
or is it the t-stat,,,

Any ideas,,,

Help,,,

Could be the hose or the cap.

Maybe a 10yr old hose....., might not look bad. But do you want to wait for failure to change. The swelling is a heads up. I would change it and cap also if it has not been done. You could pressure test it but changing those items is what I would recommend.

If the hose is soft its time to replace, chances are its your rad cap causes the boiling over
J

Look at the end of the hose- are the cloth threads in there wet or stained with antifreeze?