Yes, and having just replaced mine using drvanos' kit, a worn out VANOS sounds kind of like a diesel at idle. If you rev it, you'll hear another loud noise under the hood that has been described as rocks in a can. To me it sounds more like a coarse metallic buzz that is obvious from the VANOS unit itself.
http://www.youtube.com/watch?v=yOxd-O6NtDc