So I replaced the A/C Duct Vacuum Control Valve since it was leaking. You could hear the hissing just behind the lever, the vents worked sluggishly and when the lever was moved to "VENT" the leak was the loudest and the vents did not engage, so air was not routed through the vents. It is now fixed, the vacuum leak is gone and everything works fine. How ever I do have one remaining question. When I start up the engine, with the a/c off, as vacuum obvously starts, I can hear the vents engage. Is this normal?

I can't remember if it is normal since the car has not been a daily driver for a least one decade. I also have only driven it no more than 2-3k in the last 5 years that I can rember. So I don't recall whether I should here the vents engage or not after start up.

thanks!