Probably what's happening is that the weather sealing around the vent
flap has failed, leaving a small gap when the vent is closed. Have you
checked the sealing of the vent when it's closed?

-John

On Feb 20, 8:17 am, toad wrote:
I have a Grob 102 and it's making a very loud noise when flying fast
with the nose vent closed down. The noise comes from the nose area
and goes away when I open the vent.

I would like to be able to close the vent sometimes, because it gets
cold :-)

Any ideas what might be happening ? It didn't always do this.

Todd Smith
3S