Hello friends from MBWorld!

I have car - W212 E350 4matic Airmatic OM642.858 (3.0 195Kw) 7G tronic. Car has new engine oil, transmission oil, both diferencials oil, transimission doesnt kick.
Car has 190 thousand KM (circa 120 thousand miles)

Anybody know what this ticking sound might be? (attached video)


t only appears when i start moving with car very slowly (e.g. when i R or D, and only first few meters, then sound disappears). Sound also comes up when turning off the car.

When moving car (D or R) ticking depends on speed (faster i move the faster is ticking, but it disappears at around 5km/h ~ 3mph (i park car in garage so i can hear it very clearly).
Also, it doesnt happen all the time. There are times when i start the car and no sound can be heard.

Also, when i turn off the car it does ~5 fast ticks (as heard on video).

I have friend with exact same car and it also can be heard on his car (he is older man so he didnt hear it but i heard it when he parked in my garage).

I was with car to mechanic who works only MB cars and he told dont know what is it, but it is OK (he told he had cars with these sound and couldnt figure out what is it but there wasnt any problem with engine or transmission)

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I asked AI and ChatGPT says this:

👉 Swirl flap servomotor or EGR servomotor on the OM642

This is exactly what it does: • when shifting into D/R → the load changes, the flaps adjust briefly → a click/ticking sound • when starting to move forward/backwards → the servo adjusts the position again • after switching the engine off for 1–2 seconds → the flaps return to their “home” position, the servo calibrates → tick-tick-tick

🔊 What does the sound look like? • not metallic • not deep • not knocking • more like an electrical clicking, as if a small gear inside the servomotor is working • fast frequency: tick tick tick tick • lasts only short (1–2 seconds)

Why does it happen?

Inside the swirl flap servomotor (or EGR servo) there is a plastic gear. When it gets slightly worn, the servo tries to “find” the end position and this typical stronger clicking noise appears.

Is it a serious fault?

❌ No. It’s extremely common and does not endanger the engine or the transmission. The car drives normally. Diagnostics often doesn’t detect it at all.

Can it be fixed?

Yes, but it’s not necessary unless it gets worse: • replacing the swirl flap servomotor (approx. €100–200 depending on supplier) • sometimes replacing the whole intake manifold (if the flaps have play), but that’s rare

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I have listened to your diesel sound track for tickings and I heard none.