Horrible Engine Knocking Sound at Start Up
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Joined: Feb 2017
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C43 Coupe
Horrible Engine Knocking Sound at Start Up
For the past few days my 2017 C43 coupe with 21k mikes has made a very loud rattling/knocking sound coming from the engine bay. I can’t identify the source.
I’ve checked the oil and it was somewhat low so I put a quart of Mobile 1 5w40 in which didn’t fix the issue.
I’ve noticed that the sound 99% of the time only makes this sound while my car is at somewhat of an incline.. if it’s on flat ground, it typically doesn’t make the sound. I was due for service anyways so I just dropped the car off at the dealership and showed them the videos.
If anyone knows what this issue is or know anything about it, please let me know so maybe I can help the dealership fix it.
I’ve checked the oil and it was somewhat low so I put a quart of Mobile 1 5w40 in which didn’t fix the issue.
I’ve noticed that the sound 99% of the time only makes this sound while my car is at somewhat of an incline.. if it’s on flat ground, it typically doesn’t make the sound. I was due for service anyways so I just dropped the car off at the dealership and showed them the videos.
If anyone knows what this issue is or know anything about it, please let me know so maybe I can help the dealership fix it.
Last edited by sherrrm; Dec 19, 2019 at 09:32 PM.
MBWorld Fanatic!
Joined: Mar 2017
Posts: 1,026
Likes: 282
From: Omaha, NE
'16 AMG GTS, '21 AMG GLE53
First I've seen anything like this on our cars. Tough to tell from the video, is it a metallic or plastic sounding impact? To me, it sounds like plastic - maybe something caught in a fan somewhere?
Super Member
Joined: Feb 2016
Posts: 697
Likes: 104
From: Taiwan
GLC43, X P100D, S P100D, CT200H
For the past few days my 2017 C43 coupe with 21k mikes has made a very loud rattling/knocking sound coming from the engine bay. I can’t identify the source.
https://youtu.be/1u8LHLtiLL4
https://youtu.be/CvmF4_nG6bo
I’ve checked the oil and it was somewhat low so I put a quart of Mobile 1 5w40 in which didn’t fix the issue.
I’ve noticed that the sound 99% of the time only makes this sound while my car is at somewhat of an incline.. if it’s on flat ground, it typically doesn’t make the sound. I was due for service anyways so I just dropped the car off at the dealership and showed them the videos.
If anyone knows what this issue is or know anything about it, please let me know so maybe I can help the dealership fix it.
https://youtu.be/1u8LHLtiLL4
https://youtu.be/CvmF4_nG6bo
I’ve checked the oil and it was somewhat low so I put a quart of Mobile 1 5w40 in which didn’t fix the issue.
I’ve noticed that the sound 99% of the time only makes this sound while my car is at somewhat of an incline.. if it’s on flat ground, it typically doesn’t make the sound. I was due for service anyways so I just dropped the car off at the dealership and showed them the videos.
If anyone knows what this issue is or know anything about it, please let me know so maybe I can help the dealership fix it.
