Lower Radiator Hose Spring

Yeah, Damn right...
I'm still struggling to understand how it's likely to collapse - although don't get me wrong, I realise they wouldn't put the spring in there for no good reason. How can a pressurised system collapse? You start with a system full of coolant, and as it gets hotter, the pressure goes up. At higher revs, the pump will be drawing a quicker flow rate, so OK, the pressure drop across the pipe will be greater......
I can't remember which way the coolant flows - is it top to bottom of the radiator? If so, then are you saying that the pump is sucking against the upper end of the bottom hose, and the flow restriction of the radiator prevents enough coolant flowing in at the lower end of the hose?
What sort of a noise does it make?! I've not heard any strange noises yet....

Like a giant trying to suck the last bit of his drink through a straw.

OK, excellent description...
I'm sure I would have known if that had happened before now!
I almost want to hear it now.....

Heh.

It gets your attention.