Check out both videos I've listed below and tell us which one fits your problem.
Timing chain guide rail failure, page one of my post -
http://www.xoutpost.com/bmw-sav-foru...my-pocket.html
On second thought, if that is the sound your engine is making I would NOT run it even to check the replaced tensioner. Why? Because when you replace a tensioner and start the car, it takes several seconds for it to build up oil pressure to "tension" the chain. And, in those brief seconds if your guides have started to disintegrate it could give the chain even more slack which might allow it to jump some teeth which would be very bad. I'm not sure about this, so hopefully some others can jump in and give us their thoughts.
Youtube for "vanos rattle" -
hood rattle 2 - YouTube
I know both videos sound similar and I guess the best way I could describe the difference is that a timing chain guide rail failure sounds like an old Ford model A and you can hear it from 20ft away and the vanos rattle sounds like a diesel and is not that noticeable until you get fairly close.