"Grinding" noise when boost recedes..?
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Joined: Mar 2018
Posts: 198
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2019 C43 AMG
"Grinding" noise when boost recedes..?
Months ago I noticed a strange noise that only happens when the boost gauge slowly increases to about half and then recedes. As it recedes, there is kind of a “grinding” noise…almost like fan blades spinning and hitting the surround.
Took it to my local MB dealer and they acknowledged the noise being abnormal. Recorded a sound bite to send to MB Canada and they came back with the directions to replace drive shaft centre bearing and rubber mount.
A week later after ordering the parts from Germany and installing, the noise it still there.
Explaining to them again as too when the issue appears (turbo boost past half and receding) they decided to replace turbo charger assembly.
Ordering the turbo charger from Germany, another week passes, they install and the noise it still there.
Then on Friday they decide to order a front axle propeller shaft assembly from Germany and as you can guess…it takes about a week.
I love my car but this is getting a little ridiculous…it’s a 2019
Took it to my local MB dealer and they acknowledged the noise being abnormal. Recorded a sound bite to send to MB Canada and they came back with the directions to replace drive shaft centre bearing and rubber mount.
A week later after ordering the parts from Germany and installing, the noise it still there.
Explaining to them again as too when the issue appears (turbo boost past half and receding) they decided to replace turbo charger assembly.
Ordering the turbo charger from Germany, another week passes, they install and the noise it still there.
Then on Friday they decide to order a front axle propeller shaft assembly from Germany and as you can guess…it takes about a week.
I love my car but this is getting a little ridiculous…it’s a 2019
Thread Starter
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Joined: Mar 2018
Posts: 198
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2019 C43 AMG
The boost indicator will go to max on WOT, but the noise only happens when you slowly accelerate, the indicator gets too just over half and when it recedes the "grinding" noise appears.
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Joined: Jul 2020
Posts: 181
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From: Arizona
c450
My car makes the same noise during slow acceleration, went to two different dealers and they told me its normal? No issues with the sound apparently. After seeing this thread I think I am going to take my car back to the dealer and ask them to check it again.
Can you describe where the sound comes from?
Can you describe where the sound comes from?
Member
Joined: Jul 2020
Posts: 181
Likes: 21
From: Arizona
c450
"Sorry for the late post but had the car back at the dealer last week so they can road test the car without the traffic. Shop foreman immediately heard the noise around 1800-2300 rpm under load but he immediately said its not the normal knocking/pinging sound. Ran some diagnostics, didn't seem to have any errors, did another road test and finally determined it was clatter from insulation/heat shield in the engine bay and exhaust manifold area. He says it vibrates at certain frequencies but goes away past 2500-3000 rpm. They tightened up the area and made sure nothing was touching, so far so good. He did say these engines do sound loud/rough at times compared to Japanese cars engines which I have been used to.
Crossing my fingers hoping that noise does not come back."
Found this on a different forum
Crossing my fingers hoping that noise does not come back."
Found this on a different forum
Thread Starter
Member
Joined: Mar 2018
Posts: 198
Likes: 40
2019 C43 AMG
My car makes the same noise during slow acceleration, went to two different dealers and they told me its normal? No issues with the sound apparently. After seeing this thread I think I am going to take my car back to the dealer and ask them to check it again.
Can you describe where the sound comes from?
Can you describe where the sound comes from?
Sitting at light. Car is in Comfort. I accelerate normally (like your grandma is in the car) the boost gage slowly increases to half or just over and then car shifts. As the boost gauge recedes and resets the noise appears...only on receding, never while boost increasing. Sounds like if there were fan blades inside a metal cylinder and the blades are lightly rubbing the edges. Lasts for about 1 second and then disappears. Only really happens in shifts 1-2 and 2-3 and never seems to happen WOT.
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Super Member
Joined: Nov 2017
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2018 Mercedes C43 AMG Coupe
Are you sure it happens when receding? Sounds exactly like my wastegate rattle issue which occurs as it is building boost up to halfway. Try to get a sound clip for comparison.
I also had the exact same "heatshield/insulation tightening" procedure done like the other owner. We can't all have unfastened heatshielding... SUSPICIOUS
I also had the exact same "heatshield/insulation tightening" procedure done like the other owner. We can't all have unfastened heatshielding... SUSPICIOUS
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Joined: May 2021
Posts: 1,317
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From: Plainfield IL
Amg C43
I know it’s an older thread but I hear a similar thing but only hear it after installing new intake.
Not sound at wot but right around 30-40mph when boost recedes
maybe I put stock intake back on and see if I can hear it
Not sound at wot but right around 30-40mph when boost recedes
maybe I put stock intake back on and see if I can hear it
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Joined: Oct 2023
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2021 amg c43 cabriolet
Same sound and had back brake and rotors replaced . Dealer said chafing wrapped ..
Thought warped rotors were to blame and replace sound still there . It always happens when turning into parking garage or slowing down for a speed bump only seems to be 1500-2000 rpm .. and let foot off gas . got home and by a flug opened door and my foot goosed the gas pedal reaching for briefcase . I had sport exhaust on and just a tap and then that sound like chaffing fan blades as boost receded . I think it is loose heat shield s just getting the right vibration and casing whining chaffing metal noise . 👍 same sound when car not moving can’t be diff or bearings .
Last edited by diegobenzy; Oct 22, 2023 at 12:13 AM.
Thread Starter
Member
Joined: Mar 2018
Posts: 198
Likes: 40
2019 C43 AMG
Thought warped rotors were to blame and replace sound still there . It always happens when turning into parking garage or slowing down for a speed bump only seems to be 1500-2000 rpm .. and let foot off gas . got home and by a flug opened door and my foot goosed the gas pedal reaching for briefcase . I had sport exhaust on and just a tap and then that sound like chaffing fan blades as boost receded . I think it is loose heat shield s just getting the right vibration and casing whining chaffing metal noise . 👍 same sound when car not moving can’t be diff or bearings .
