[sick472]

The concept of collapsing the hose when a clogged radiator is present merely means that the difference in pressure from before and after the pump is sufficient enough to suck the hose in because of a difference in pressure from before and after the cooling tubes of the radiator. These differences in pressure always exist, but are not always enough to collapse the lower hose. When the radiator gets gummed-up (or undersized) it will not allow the pump to draw as much coolant and the hose gives in.

A warmed up motor will add an over all pressure to the system which further decreases the magnitudes of the pressure differences. This will reduce the likelihood of collapsing a hose by giving the inlet side of the pump a bit more pressure to aid the flow of the coolant to the pump. This added pressure also helps to keep the hose expanded.

If your high volume water pump is collapsing your lower hose under warmed up conditions and a clean radiator, I would surmise that you could use a better flowing radiator to get everything you can out of the pump (or you don't need the high flow pump).

A spring will cure the symptom (collapsing hose), but does not cure the cause (high delta P's across the pump and radiator). The pump would still be starving to some extent just not sucking the hose in.

I am not really arguing for the idea of NOT putting the springs in, I think all my engines have them. They are a nice thing to have to avoid completely starving the pump (peace of mind) under the right/wrong conditions, but I would say that the are not necessary with a properly designed and maintained system.