IIRC 270 is the upper limit of my Silverado. Every lb of pressure the cap can maintain raises the waters boiling point 3 degrees. That's a 17 lb cap. If a hose blows at 17 psi its rotted, they are rated at >200 psi new! And a heater core is capable of ~100 psi...C'mon guys give these a little credit. I dont think either is the weak link. I would think the OEM spring "constant pressure" type clamps would blow the hose off before a decent hose lets go. And yeah, they do wear out, change them out at 100K or whenever the hose tells you. They usually start to bulge when they start losing strength.
