ML320 Airbox Silencer/Restrictor
 

(Note - used the search, found nothing. Topic also posted in M/G/Uni forum.)

Gang:

Hope that you can help me out with this one. Yesterday I was digging around in the engine bay of the wife's 2000 model ML320, and I found something interesting inside the airbox. As you're doubtless aware, the airbox is a dual-inlet design. There is a (pseudo) ram-air tube into the front of the 'box, and a second inlet from the passenger's side fender well. There is a large, triangular hole in the fender which lines up with a large, triangular hole in the airbox. The gap is sealed (well, at that) by a foam insert. The foam is visible with the airbox assembly in place.

Imagine my curiosity when I found an injection-molded plastic piece snapped into the large triangular hole in the airbox. This fit tightly into the hole and reduced the generous inlet area to a circular hole of perhaps an inch in diameter.

Needless to say, this is now removed and resting quietly in the glove box. This serves no structural purpose, and apparently does nothing except restrict airflow (rob horsepower) and possibly silence intake honk a little (can't hear a difference).

Does anybody know anything about this piece and its ultimate purpose? Is removing this a common and/or effective modification?

To keep water from being sucked into the engine & causing the engine to "HYDRO-LOCK". These are OFF-ROAD trucks you know. MB lost several engines to hydro-lock in ALABAMA at the MB off-road test site, durning the first testing.
That is why there are 2 air intakes!

'Doc:

Insert or not, there are still two intake holes. The insert simply makes the fender hole smaller in area (and less efficient).

Can you hook me up with some more information? I can't see how that insert reduces the likelihood of ingesting water during a deep-water ford...

I also realize that the M-Class is theoretically capable of doing a bit of off-roading, but I've yet to see anyone take one out stump-jumping like I used to with my father's GMC (rest its poor soul) back in the day.

...Never Mind!
 

Already located the information. Back in it goes. Damn Benz engineers...

The takeaway - Don't let a drag racer tinker with your off-road ride.