I have submitted a few times on here discussing the problems with my 2009 C230 4MATIC with the pulsing vibration that I note when the car is idling at a traffic light with my foot on the brake. The vibration mostly disappears when the car is put into neutral. I have had these issues with the car from almost day one after purchasing new.

There are several W204 owners on here that have the same problem. There was much discussion about this cabin vibration issues where causes such as ‘low idle’, ‘plug problems’, ‘defective brake boosters’, ‘steering’, ‘motor mounts’, etc. were shared. I had previously mentioned that I had the motor mounts replaced under warranty and the problem did not go away.

I noticed that when the car is under load, the vibration gets worse (while the added load is being applied). Air conditioner especially. Sometimes even opening the window makes it worse (when idling with foot on brake).

Yesterday, I took my car to a friend that works on cars and engines, and owns several Mercedes. I had him look under the hood. I put the car in gear with my foot on the brake, and he observed that there was quite a bit of movement ‘giggle’ in the belt tensioner when the car is in drive versus when the car is in park, neutral or reverse. He also noticed some wobble in the crank pully? (cannot remember the exact name he used).

I am no car expert. When I bring the car into the dealer they are not able to locate the issue of the ‘pulsing’ vibration that I feel in the cabin when I am idling at the lights. I have never mentioned the pulley and belt tensioner as possible causes, not sure if the dealer has even looked.

Is it possible that the above issues could be causing the vibration that I feel in the cabin? How much is the belt tensioner supposed to move? Is the crank pulley supposed to have a very slight wobble?

The car is under warranty, and I just would like to get a bit more info before I take back to the dealer.

Any help that any of you can provide would be sincerely appreciated.


Thanks in advance!


t.

Ask to take a technician or foreman out on a ride to demo the problem. I had to do that with my car while it was under warranty.

Did you have the same problem with your car? If so, what was the end result? What did they end up changing?

My idler pulley came in correctly shimmed from the factory, got it fixed under warranty.

What problems was the car exhibiting before the correction? How did you know you had a problem? How does it run now?

It was causing premature wear on the belts, and bearings on the pulleys. Also caused the bearing to squeal. It's all fixed now.

Same thing with my 08 4-matic. The tech supposedly located the problem. He said the issue is with my "axel shaft" and it and the joint were out of balance? He said it is a common issue with the 4-matics. Good luck when you bring it in. I am hoping to pick up my c300 tomorrow with no issues remaining.

fyi: the service manager told me a guy he knows is going to put on the latest gps maps on my car for $100 cash...just thought i would share...anyone else get offered this or know someone that does it (no i havent searched for it, $100 is more than worth the time i save)

Wish I heard that before my warranty ran out, I took my car in for vibration issues and the dealer "couldn't duplicate the problem." Let us know if it fixes it.

Read the post again:

I have submitted a few times on here discussing the problems with my 2009 C230 4MATIC with the pulsing vibration that I note when the car is idling at a traffic light with my foot on the brake. The vibration mostly disappears when the car is put into neutral.

Since when the car is not moving, no part of the drive train is rotating so how is this related to this problem??

I'm pretty confident we share the same symptoms/ problem. However, I will find out exactly what they had replaced today when i pick up my car. That terminology was used by the service manager, not the tech so he could have misstated something. It could be that something is bent and is causing the vibration? Whatever it is, they seem to be confident that they have targeted the problem.

We will see if this fixes the issue.

Looking forward to hearing what the problem was, the fix, and the outcome. many of us are frustrated with our cabin/idle vibration issues with the W204's. Anything you can share will be of use when I go back to the dealer with my pully/belt tensioner observations....

Follow-up:

Mercedes mechanic looked at my car and found that the left front axel shaft had movement in the joint which was causing vibration when at a stop. He said this is a common problem with the 4-matics. The axel shaft/ drive shaft were replaced and the problem is now fixed.

Thanks for that information, I will mention it to my service manager when I bring my car in...

I have the exact same problem with my 4 matic too. But I find this problem common among really old cars or high mileage cars.
Looking forward to see more about what the problem is.
Hopefully it's not from axel shaft because my warranty is out and it would cost a good amount...

My 08 is 4 years old and only has 37,000km on it. This isn't a high mileage/old problem. It's a Mercedes/4matic problem.

There have been numerous people with it. All 4matic owners. If you look into the Subaru Outback (another AWD car), axle vibration problems are common as well. All with the same symptoms of rough idle in Drive while at a stand still. Shifting to Neutral is smooth.

I'm pretty pissed off my dealer couldn't work it out. When I have to research the hell out of all my own issues and tell the dealer how to fix them, you've got to wonder what the point of warranty is.

I had to do that with my car while it was under warranty.

I took my 2009 C230 4 MATIC into the dealer on Friday to have them look at the belt tensioner and idler pully as possible sources of the pulsing idle vibration that affect the car in idle while braked at a set of lights. These things turned out to be ok. They had the vehicle for 2 days, so they checked each of the cyclinders with a tester and found that Cyclinder #6 had a slight misfire due to a coil that had a slight malfunciton. Not enough to throw any engine checklights, but enough to show a fault on the engine tester.

Anyway, they replaced the one coil and the plug for the cyclinder. Took the car home that evening and noticed a significant improvement. Although there is still the slight constant vibration in the wheel, it has reduced significantly, and I no longer feel the pulsing in the seat pan. I also notice that there is less vibration that kicks in when I turn on any accessories. For sure this was one fix that has made a significant difference. Will monitor and keep everyone up to date.