Quote:

It use to be ALL new lower hoses came with a spring already in them.

Not any more

Without it the pump at high rpm's can suck the hose closed.

Not the thing that you would want

If you can find one put it in. I try to save the old ones when ever I can



I'm trying to figure out how the hose could get sucked closed. I think that the cooling system is a closed system with no air in it. Full of liquid coolant. If everything is full at idle engine speed--block, heads, pump, hoses, etc.--which comprise the total volume of the system, and we diminish the volume of the system by collapsing a hose, where does the the liquid coolant go? Does it expand another hose? Liquids, including water and ethylene glycol, essentially are incompressible fluids aren't they? I'm referring to a system with a coolant reservoir and two-way vented filler cap.