Can Cooling System be Sealed Too Tight ?

Is it possible to have a cooling system sealed up too tight ?

Xterra 2001 V6 2wd.144k miles...Replaced leaking radiator with aftermarket unit which installed trouble free (including bleed off of air) EXCEPT...original radiator cap is really really snug fit (cap rubber seal is slightly larger diameter than ID of radiator cap opening) on new radiator and when the system cools down, the upper radiator hose collapses flat for about half the length.

It looks like the cap is sealed up so tight the overflow/expansion tank won't function.

It can't be good for the hose to collapse/expand everytime system heats/cools down...

so...

any suggestions before I buy caps and find one with a better fit ?

related question, how loose/snug should cap slip into top opening. OEM cap on OEM radiator was very loose with almost no resistance...it felt like the cap spring held the sealing rubber down on the inner rim snug but the rubber seal didn't seal the perimeter edges if that makes sense.

[jacko48j]

When the upper hose collapses it means you need a new cap. And it should not be a struggle to get the cap on and twisted tight. You want it snug but not to where it's hard to get on and off. Maybe the new cap will fit better.

Thanks for confirming what at first seemed obvious, but you never know.

My hope is the radiator source has a cap matching their radiator...my fear is another OEM cap would be similarly sized and too tight.

Push comes to shove I will shave or notch the OEM cap until it loosens up enough to function properly.