Ml 350 bluetec engine noise om642 engine
Thread Starter
Junior Member
Joined: Jul 2020
Posts: 16
Likes: 4
Ml 350 bluetec
Ml 350 bluetec engine noise om642 engine
Hello,
I have a ml350 bluetec diesel 2012, 107k miles on the clock. Noticed this noise from the passenger side of the engine. Sounds like a knock or a hiss. It is very pronounced. An indy mechanic told me it is normal, but it does nor sound like it to me. Please help what can it be?
Links to sound in the videos below:
https://youtu.be/k995O8dVRgQ
https://youtu.be/iAeSgyzsmww
Thank you so much to anyone who can give me an opinion!
I have a ml350 bluetec diesel 2012, 107k miles on the clock. Noticed this noise from the passenger side of the engine. Sounds like a knock or a hiss. It is very pronounced. An indy mechanic told me it is normal, but it does nor sound like it to me. Please help what can it be?
Links to sound in the videos below:
https://youtu.be/k995O8dVRgQ
https://youtu.be/iAeSgyzsmww
Thank you so much to anyone who can give me an opinion!
Thread Starter
Junior Member
Joined: Jul 2020
Posts: 16
Likes: 4
Ml 350 bluetec
Thanks for your reply. From my knowledge timing chain stretch can be heard only at cold start, and this was after I drove the car a bit. I fear it is either an injector seal, or something much worse, like a bearing knock. This is my first diesel, and I can't really understand what is a normal noise and what is not. Scratching my head here....
Senior Member
Joined: Jul 2017
Posts: 487
Likes: 114
From: DFW, TX
Ml350 bluetec
At this point, I would get a 2nd opinion from another shop. Diesels make rattling noises due to compression ignition, most noticeable with the older style US pickup trucks. Less noticeable in our Bluetecs. That knocking sound is definitely not normal.
Out Of Control!!
Joined: Sep 2018
Posts: 14,679
Likes: 4,578
From: unbegrenzt
2017 GLE350 4MATIC
Not sure what we are trying to hear. I listened to and watched both videos.
Sounds very much like a diesel engine.
If it is something with a periodic nature then it is related to the induction or exhaust system.
Is it higher, or lower, on the engine?
Is it toward the front, or the rear, of the engine?
You said it is on the passenger side, this is where a lot of induction hardware is located.
Search this site. There are some threads on (I think) intercooler and charge pipe failures.
Search this site.
Sounds very much like a diesel engine.
If it is something with a periodic nature then it is related to the induction or exhaust system.
Is it higher, or lower, on the engine?
Is it toward the front, or the rear, of the engine?
You said it is on the passenger side, this is where a lot of induction hardware is located.
Search this site. There are some threads on (I think) intercooler and charge pipe failures.
Search this site.
Thread Starter
Junior Member
Joined: Jul 2020
Posts: 16
Likes: 4
Ml 350 bluetec
Not sure what we are trying to hear. I listened to and watched both videos.
Sounds very much like a diesel engine.
If it is something with a periodic nature then it is related to the induction or exhaust system.
Is it higher, or lower, on the engine?
Is it toward the front, or the rear, of the engine?
You said it is on the passenger side, this is where a lot of induction hardware is located.
Search this site. There are some threads on (I think) intercooler and charge pipe failures.
Search this site.
Sounds very much like a diesel engine.
If it is something with a periodic nature then it is related to the induction or exhaust system.
Is it higher, or lower, on the engine?
Is it toward the front, or the rear, of the engine?
You said it is on the passenger side, this is where a lot of induction hardware is located.
Search this site. There are some threads on (I think) intercooler and charge pipe failures.
Search this site.
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Thread Starter
Junior Member
Joined: Jul 2020
Posts: 16
Likes: 4
Ml 350 bluetec
Thank you to everyone for your answers. I wanted to know what the engine noise was, but I am also hearing a faint thump coming from below the car when I press the gas on 50-60 mph. I do not hear it at low speeds or city driving. I fear something with the transfer case. Both the noise from below and the noise in the engine brought me to the stealership for a full diagnosis. In the waiting room now anxious to know what they will tell me. I will let you know once I get the results.
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Junior Member
Joined: Oct 2009
Posts: 64
Likes: 0
From: New York City
2014 ML63
Having very similar sound, after water pump was changed, and mechanic changed one of the injectors ( after he saw carbon build up / and fuel leakage from one of the injectors on passenger ride)
and we can correct the issue, will be a month now . trying to avoid opening up the valve cover .
