Does a vacuum leak whistle?

Since a vacuum leak is basically an opening in a suctioned area, it is possible. The best way to check would be to either use a vacuum gauge and connect it to any of your vacuum lines while plugging the other side.
Another good way to tell if you have a vacuum leak is to put soapy water around your intake manifold and any other vacuum areas. If you see bubbles or the water being sucked inside, you have just discovered your vacuum leak location.

Hope this is helpful