Gregory.C

Hello all. After enjoying this forum a bunch since I bought my 2003 E320 4MATIC wagon last June, I finally need to ask your assistance. I am getting a strange clunk in my undercarriage. Here's what it sounds like: you've got a hard rubber mallet in your hand, and you whack the side of a mostly full 55-gallon oil drum. It's a sort of a dull clunk, and can be quite loud. It's hard to tell where it's coming from; except to say that it's definitely in the undercarriage. It happens at any unpredictable time. Not with a bump in the road, not necessarily in the hot or cold, with the car cold or hot, running or parked. I even heard it across a parking lot when the car had been sitting for two hours. Any ideas? Thanks so much.

ohlord

first,check your springs and all suspension bushings.Next check coolant level,a bubble or gap in the anti freeze solution could create a loud burst inside the engine coolant passages.If you can't find it soon,better get it to a shop before it gets worse.
Third,you need to be in the w211 section and they may suggest a few other things to check,like that pesky sbc braking system that is known to make all kinds of strange sounds

RECALL: 2003 - 2005 Mercedes E-Class
NHTSA Campaign Number: 04V296000

www.nhtsa.dot.gov
Manufacturer MERCEDES-BENZ USA, LLC.
Recall Date: JUN 22, 2004
Potential Number Of Units Affected: 143387
Description SERVICE BRAKES, HYDRAULIC
Summary ON CERTAIN VEHICLES, THE ELECTRONIC MONITORING SYSTEM OF THE SENSOTRONIC BRAKE CONTROL (SBC) IS DESIGNED TO MONITOR THE PRESSURE GRADIENT WITHIN THE HIGH PRESSURE LINE OF THE BRAKE SYSTEM. IF AN UNACCEPTABLE PRESSURE GRADIENT IS DETECTED, THE SYSTEM WILL SWITCH, AS IT IS DESIGNED TO DO, INTO THE HYDRAULIC FUNCTION MODE.
Consequence IF VEHICLES ARE NOT ROUTINELY SERVICED AND HAVE EXTREMELY HIGH MILEAGE COMBINED WITH A HIGH NUMBER OF BRAKE ACTUATIONS, OR A HIGH BRAKE ACTUATION FREQUENCY, THE PUMP MOTOR OF THE SBC MAY RUN OUT OF PERMISSIBLE TOLERANCES, THEREBY TRIGGERING THE HYDRAULIC FUNCTION MODE.
Remedy DEALERS WILL INSPECT THE SBC HYDRAULIC UNIT, REPLACING IT IF NECESSARY. THE RECALL BEGAN ON OCTOBER 21M 2004. OWNERS SHOULD CONTACT MERCEDES-BENZ AT 1-800-367-6372.

So go to the w211 forum,ask around,good luck
ohlord

Gregory.C

Thanks for the excellent advice ohlord. (That comes out well with your username, doesn't it?) I'll suggest to the dealer that they look at those things. BTW, I'm on an MB Certified warranty, and hoping they'll find it! When I described it on the phone, they had no concrete thoughts, although they did mention the springs as a possibility. They want to keep the car for a full day, and hope the sound happens. It may, and it may not... Thanks.

Eurosport

ah those lovely control arms

suicidal4life

I could be wrong here but didn't the W210 wagon continue into 2003? Gregory did mention that his car is a wagon.

RobertG

This sound like the fuel tank expanding or colapsing.

ohlord

catch it is a wagon.So the sbc is out,now he just needs to get all those other things and an expanding gas tank looked at.