I have had an annoying rattle in my 300E since I purchased it 6 years ago. It seemed to come from the front and only happened when I hit a sharp bump at low speeds. It was a very solid clunk sound that I could not seem to isolate in the garage. A post about the impact strip on the rear
bumper comming loose got me to thinking that might be the problem so I removed the bumper only to find the impact strip was properly attached but the foam blocks inside the bumper assembly have
dried out and shrunk enough that they can move
about when a sharp bump is hit. I used RTV to
attach them to the bumper cover and my rattle is now gone.

__________________
Dave
88 300E 250K Sold
2000 C230K Totaled @104K
2003 ML320 156K Sold
2009 E350 4Matic Sport 46K Sold
2011 ML350 60K Sold
2014 GLK350 46k Sold
2012 GL450 67K
2016 E550 Cabriolet 48K