'99 C230K Drivetrain Vibration
 

Anyone experience a drivetrain vibration from 40-75+ MPH. Can feel this under a load or straight & level w/cruise control on. It feels the same as my '72 Impala did when the u-joint went out.

So far, the wheels were road-force balanced & rotated, upper LH control arm replaced, and both lower ball joints replaced.

The car has 33K on it and otherwise in perfect condition. I can feel the vibration on the floorboard, gas pedal and steering wheel a little. Thanks in advance for the help. -Mike

Without looking at the car or driving the car I may guess that the motor mounts and possible trans mount may be collapsed and in bad shape.

Does the car feel rough in your seat upon start up?
That could mean low motor mounts.
You may want to check the flex disks on front and rear of driveshaft and also check the driveshaft out well.

Check all your suspension components out well and also look at the steering shock/dampener.
You can unbolt one end of the dampener and see if it moves freely in and out with little resistance then it's no good.
A good steering shock will move very slowly in and out while you push it in and pull it out like a shock absorber.

I'd say get the car on a lift and have it gone over and test driven to try to pinpoint the problem.

I second flex discs.

Rubber is age-affected, obviously, and they are probably cracked.

Engine mounts might be the culprit, but you generally notice them more when shifting into gear from park. But, while you (or a mechanic) is under the car, check the engine/trans mounts and the flex discs. Your C-Class does not have a floating diff, so there are no u-joints as per your old Impala, but instead uses a solid driveshaft that has rubber dics at each end to absorb vibration and torque changes. As mentioned, they age with time, not mileage.

In fact, most of your car might seem to be "giving out" at a prematurely low odo reading, but cars age with time as much, if not more, than with mileage, so don't be too shocked if you need a few things over the next little while. Some things that C-Classes (W202) seem to need as they get to the 8-10 year age...

Engine mounts
Sway bar bushings
Control arm bushings
Engine accessory drive belt tensioner
Some emission control bits (charcoal cannister, purge valve, etc...)

Is there an easy way to check out the motor mounts or does the engine have to be lifted to take the pressure off of the mounts? Also, flex disks on the drive shaft? Is this a replacement for u-joints? Is it obvious when they wear? Guess it's time to climb underneath and see what I bought.

I firmly believe if it is speed-dependent, not RPM-dependent or not happening the whole time the motor is running, it's not the mounts. If it is while in gear, at speed, it is very likely the flex discs.

Ya know, Blackmercedes, what o you think about the tensioner spring ( ithink)? There is a piece that goes with the tensioner and I can;t recall exactly what it is. I've heard these cause shuddering. Minewas replaced under warranty, when I complained about engine rougness, but I don't personally remember it being that bad, but my seat of the pants is different than others

UPDATE UPDATE UPDATE Car went back to the local Mercedes dealer this morning. Checked driveshaft flex joints, tranny mounts, and engine mounts-no problems found. They suspect the Continentals may be out of round or have a small ply separation. They're swapping out the wheels with another car on the lot. If this is it, I'll be getting a new set of tires out of the deal. (bumper-to-bumper warranty, right?) Should have an answer tomorow. Will advise -Mike

Hahah!
 

Sorry, not funny, BUT - if I had thought harder, I would have rememeber I had an OOR Conti on mine that ALSO caused the shimmy you mention.

Amazing. What a crap tire. I'd love to know the percentage of OOR Contis as opposed to Michelins. I"ve heard this more than a few times

Makes me a little sceptical ?:confused:

UPDATE UPDATE UPDATE The dealer swapped out the wheels with another car on the lot and guess what went away... the road vibration. Now the MB dealer is waiting for the OK from the dealer I purchased the car to replace the Conti's with Michelins. The tech said it drives like a different car. Haven't driven it yet, but I have a loaner (2006 C280) which drives like a charm. THANKS everyone for the help!!!!! -Mike

Glad to hear it. You will get lots of opinions, but I've had contis, coopers, bridgestones, and now Michelin Pilots, and these cars are made for Michelins. You will be happy