Weird vibration on W202
 

Hey, all,

I know this is a much-discussed topic around here, but I'm hoping someone's been through this, or might have a logical way for me to check it out. A search availed me nothing.

Car: W202, '97 C230, 68K. Great condition; very quiet inside -- except . . .

. . . when I run over those ripple-bumps. You know the sort of thing -- concrete, with the little waves set just close enough that they set up a resonant vibration in your cabin. I hear it nearly every morning on my commute across the rough surface of the Miss. River bridge, esp. if the A/C is on and the windows are therefore closed. It's faint, I admit -- if I'm playing music instead of a talk station, or if the windows are slightly open, it's hard to detect -- but it's there, and I know the car didn't do this when I bought it a year ago.

Speed doesn't seem to matter -- I hear it at 35 as well as at 50, if the road is bad. Tires are at 30/34, but I heard it even at the recommended 28/32.

The A/C cabin filter has been replaced, and its retaining panel and clips are tight. Nothing seems to even flex in the dashboard/console area. The noise is not metallic-sounding, and taking things out of the glove box before a drive doesn't prevent it. I'll try driving with windows up and A/C off for a while tomorrow morning (and in this heat and humidity, that's a sacrifice) to see if it might be the A/C system. (Could it be a wheel balancing is needed? Car drives beautifully on a smooth road.)

Has anybody else had this happen on a W202? There are so many rough, ripply patches in what are laughingly called streets around New Orleans that it's a pain to live with. What could I look for? Or would my mechanic have to dig into the dash?

TIA!

It's pretty likely that your lower ball joints are worn and loose. With the car on a lift or jack stands with the wheels off the ground, you can apply an upward force to the wheel. While doing this watch the ball joint. Any play warrants replacement. Not exactly an easy job for the do it yourself'er though not impossible for the determined.

It may well be ball joints (though ours are still good, I'm told, at 98k miles). But first, do you have the split fold down rear seat option? Ours sounds a bit like this on rough roads if the seats are not completely (hard!) latched upright - amazing what sounds come out of that trunk area. I am tempted to dynamat the entire trunk. The sound seemed to come from up front, but my wife had to ride in the back once, and she noticed that the seat back moved slightly. We re-slammed the seats closed, and the sound went away.

Thanks to duxthe1 and JCE,

No, I don't have the split seat, or the pass-through from the trunk option, either. Ball joints? Urgh. Though I've noticed from other posts that the W202 can be hard on such suspension components when driven on rough roads. I'll try jacking it up and checking. It's not something I could do myself -- I don't have the space or the tools. I guess I'll put it down to normal maintenance, if it turns out I need to have these done.