I had a low speed clunk on my 2009. Supplying dealer and MB specialist had a look but could find no play in any part of the suspension. I eventually found the answer myself in this service bulletin. It was the strut.
Front Strut / Shock Tower: By Symptom
Technical Service Bulletin # LI32-25_P-048381
Date: 091208
Suspension - Front Axle Dull Thumping Noise On Bumps
NOISES FROM VICINITY OF FRONT AXLE ON UNEVEN ROAD SURFACE
Topic number
LI32.25-P-048381
Version
1
Design group
32.25 Shock absorbers/damper struts/spring struts
Date
12-08-2009
Validity
Model 204 without code 483 (Vehicle dynamics package), without AMG; Model 204.0## #A 185017 up to * 195993 with head bearing
Reason for change
Topic extended to FA shock absorber / torsion bar linkage. / Supersedes DTB P-B-32.25/67
Reason for block
Complaint:
Dull thumping noises or metallic rattling from vicinity of front axle on slightly uneven road surface and/or repaired road surface.
Note:
Noises occur in lower speed range (20...approx. 70km/h).
Cause:
Several causes are possible:
1. Head bearings on front axle suspension struts are too stiff (Shore hardness).
Note:
Noises from the head bearing occur on more uneven surfaces and sound relatively dull.
This cause affects only a small, limited production batch! Pay attention to the VIN restriction for head bearings (EPC: "Bearing, suspension strut to
body") in Validity section! On vehicles outside the restriction range, the head bearing is not the cause of the noise and may therefore not be replaced.
2. Shock absorber
Note:
Noises from the shock absorber are audible on slightly uneven surfaces and sound rather more metallic.
3. Torsion bar linkage
Note:
Noises caused by a torsion bar linkage only occur in a very small number of cases on this model series.
