Vibrations Begin at a Speed of 120 Km/h

[xsesiv]

I fixed the high speed vibration on my W166 by replacing the front left lower control arm. The rear bushing in this arm is worn, allowing the wheel to move back and forth. I found aftermarket options to replace just the bushings, but ended up replacing the entire arm that came with the bushings.
This same car had vibrations at idle and low revs, which were eliminated by replacing the active engine mounts. The old mounts were leaking.

 

[novembro]

I choose tires as mentioned earlier. At a certain speed, low frequency vibrations start to become a noticeable frequency, and if you reach a certain Hz value, the car may start to hum.

 

[hafsa]

I had a similar problem, I solved it by replacing one injector.

 

[MBtreestump]

A friend had the same problem with his W166, no fault code, transmission worked smoothly. He installed winter tires at the first stage, no change. Disassembled the front and rear brake and checked for problems. Everything seemed fine. He sent the driveshaft for balancing. The workshop said it was balanced. Just in case, he replaced the front suspension arm, as well as the brake discs and pads. He eventually discovered that one engine mount was broken, but there was no leak. He used a wooden wedge and inserted it between the frame and the rubber suspension points. When he got to the left engine mount, the high-speed vibration was gone (a slight constant vibration was present due to the wedge during testing).

 

[IlanISR]

Solved! It took a while, but here's the update.
We started by balancing the wheels and tires in three different shops, but unfortunately this did not solve the problem.
The cause appeared to be the transmission, as it was causing a high frequency vibration.
I decided to start with the transmission torque converter. When my W166 reached 100,000 km it was time to service the transmission and I added an anti-shudder additive to the torque converter. I have had good experiences with this product since I became a Jeep owner.

While working on the transmission, the mechanic noticed that a bolt was missing from the front drive shaft:


When we tried to insert the bolt, it turned out that there was no thread, so we fixed that too.
Thanks to the new transmission fluid and filter, and the installation of the missing bolt, my W166 is vibration-free, as confirmed by tests at speeds up to 160 km/h. There are still some things that need to be fixed, but I'm starting to like this beast.

 

[Alexu]

The same thing happened to my car. I found that the subframe was rusted and partially broken.

 

[M156]

Had the same problem on W164. Vibration damaged the drive shaft bearing. You can check if there is too much play.

 

[Bari87]

The W204/W212 had common problems with rusty rear axles. Mercedes will replace them as part of their "30-year rust-free guarantee" (almost a marketing/advertising joke).