When I drive my car then sometimes I suddenly hear a noise.
I have searched the forum for similar problems. But without finding anything. If there are threads with similar problems, please let me know.

When I drive my car. Then I sometimes can hear a noise from the rear (I think) of my vehicle. It is a Mercedes-Benz E 220 CDI Sedan (w212) 2wd 2014. The car has 100.000 km on the meter.

I think it's tricky to drive in a way so that I can clearly hear the noise.
The noise just happens sometimes, from time to time.

Of course, when I drive in pot holes it makes some noise. But then the whole car jumps and starts making noise. So when I drive in a pot hole, it is not easy to say what wheel or what caused the noise.

Or what kind of movement that created the noise.

It sounds like a rattle (sometimes) or slow knocking sound, but it is not very loud. The opposite actually, it is a quite low knocking sound. With a low frequency. It is not repeating over and over again. The sound seldom happens once or twice.

I can hear the sound a little from time to time occasionally when I'm driving the car.

I can not find a simple, practical use case to trigger the noise.
It just suddenly happens, suddenly I can hear the quiet low noise.

When I switched to winter tires, I noticed that the summer tires were a bit worn on the inside (I think) of the tire. Obviously the wheel angles need to be adjusted.

When I switched from summer tires to winter tires, I noticed that the summer tires were a bit worn on the inside (I think) of the rear tires. Obviously the wheel angles need to be adjusted.

But before I do that I like to understand and fix the noise. Where does the noise come from? I have checked the wheel bearings but it does not seem to be the wheel bearings.

Do you have any suggestions as to what it can be?
How should I be able to drive in a way that I can hear the noise to find the problem?
How can I fix the problem?

 

Imo could be many things related to the rear suspension or brakes if you say the sound is localized to the rear. I would try to get the vehicle on a car lift and start by checking the control arms, bushings, shocks, springs, subframe and exhaust hangers. The subframe is a known issue in these vehicles (the warranty on subframe was extended by MB for 20 years recently) as they are prone to rust out especially if there is heavy use of salt during the winter to clear the snow on the roads. If you're not mechanically inclined and would more than likely bring the vehicle into a garage to get repaired, then the mechanic would take the vehicle out for a test drive to replicate the sound and track down the origins.

 

Change your suspension wear parts:

• lower control arms
• ball joints
• stabilizer links
• (shock absorbers)
• (stabilizer bar/bushings)
• (wheel bearings)

Usually front end components age faster than the rear ones.

The commonality is rubber parts age into chewing-gum: everything must go! Start with most stressed parts.
✌️

 

Any number of things but also check the rear brakes and make sure the retaining clips are installed. Had a knock sound that was only audible when going over bumps with a wall to reverberate the sound back at me. When I did my brakes found right rear was missing. Got one installed and the noise went away. Well that noise anyways.