Does anyone think it is the radiator besides me?

Friend of mine years ago had a problem with LOOSE SCALE coming out of the block. It would not really plug the radiator, just get sucked into the bottom tank and up against the bottom of the core. You could take off the radiator and "fail to notice" that a little bit of loose scale fell out the bottom.

YES it would suck the hose shut, the hose had a spring in, and it damn near would rip the bottom hose outlet out of the radiator at high RPM

As for a shroud, does not mean squat on the highway. You should be able to pull the fan clear off the car on the highway.