Engine noise

Page may contain affiliate links. Please see terms for details.

KRL

New Member
Joined
Jan 24, 2023
Messages
7
Location
Scotland
Car
Mercedes CLS 350D
Hi everyone,

Thanks in advance for any input/advice.

I recently bought my first Mercedes and need some help identifying a noise from under the bonnet that I haven’t heard in other brand cars I owned. It happens when the car engine is idling and can be heard as clicking/ticking noise, almost like a clock ticking every second. Is this something I should be concerned about? What could be the source? I recorded the sound and uploaded to YouTube if anyone wants to have a listen:

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

The car is a 2018 CLS 350d
 
Seems a touch louder then my 350d, or maybe the phone recording makes it seem louder.

Was that recorded when engine was cold.
 
Maybe a bomb......

Sounds totally normal to me
Thanks for your reply. Do you know which component it’s coming from? I’ve not heard that on other cars that I owned (also 6 cylinder diesels).
 
Seems a touch louder then my 350d, or maybe the phone recording makes it seem louder.

Was that recorded when engine was cold.
Thanks for the reply. The engine was warm, but it sounds the same cold as far as I could tell. Yes the loudness might be amplified on the video as I had my phone very close to the engine but it’s loud enough to be heard with the bonnet closed, standing next to the car.
 
Last edited:
Anyone else have any ideas? I’m curious to identify which component is generating that noise and why.
 
Is it constant or intermittent? Both my E classes have made the same sound but on both it seemed to come from underneath the drivers door area, both different engines, but same sound and only occasional, not as loud though (unless as above it is amplified by the phone). I put it down to DPF related and didn’t have any problems. I too would be interested to know what it is though.
 
  • Like
Reactions: KRL
Is it constant or intermittent? Both my E classes have made the same sound but on both it seemed to come from underneath the drivers door area, both different engines, but same sound and only occasional, not as loud though (unless as above it is amplified by the phone). I put it down to DPF related and didn’t have any problems. I too would be interested to know what it is though.

Took the car for a drive this morning and had a listen before and after. With the engine cold I could not hear anything but after I came back (about 30 min drive) the “clicking” was there 🤔
 
Timing chain springs to mind straight away after hearing video….

Thanks for the suggestion. Would timing chain noise be there consistently all the time regardless of the engine being warm or cold?
 
Your best bet would be to get a garage check it out, they will get to the bottom of it, if there is something wrong.

Please report back on the diagnosis.
 
Your best bet would be to get a garage check it out, they will get to the bottom of it, if there is something wrong.

Please report back on the diagnosis.

Spoke with the garage and they assured me that Mercedes-approved cars go through thorough checks before being sold and if there was something wrong they would pick it up during diagnostics. As much as I want to believe them there is always some doubt, the sound seem out of place to me but could be normal with Mercs. That’s something I was hoping to clarify/identify with help of others on this forum.
 
Sounds normal to me, it is a diesel after all and they work on much higher compressions than a petrol when the injectors force the fuel in hence the popping noise.
 
  • Like
Reactions: KRL

Users who are viewing this thread

Back
Top Bottom