Re: Why would my Top Radiator Hose collapse?
If the hose collaspes after it is shut off (and cools), then the return valve in the cap is plugged, not allowing coolant (or air if no overflow bottle) to return to the radiator. New cap should fix it. Also, if you use any radiator sealer, it can block the cap return. On two different cars I had to flush the cooling system out to remove the sealer, otherwise I was having to replace the caps every couple weeks.
2012 Camaro SS
03 Suburban 2500 8.1L - Tow Pig
75 MGB - eternal project
67 El Camino - Sold