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Discussion Starter · #1 ·
I am the owner of a 2017 model 2.1 Diesel AMG premium plus and have noticed over the last few weeks a pinking metallic sound when accelerating , when I take my foot of the accelerator the sound stops . I plan to take to the dealer for a look but wondering if anyone else has had this problem . It happens when hot or cold . No noise when just idling .
 

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Yes it’s a common characteristic with this engine and has been discussed many times, some put the noise down to when the car is going through a regen cycle, or using a low grade fuel etc, I pay no attention to it anymore and 2 years down the road nothing has come of it so just put it out of your mind and enjoy your car. A few have taken it to the dealers only for a no fault found diagnosis.
 

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Discussion Starter · #3 ·
Ok , thank you . I am sure the sound was not there at first . Will possibly try some premium fuel on my next fill to see if it makes any difference .
 

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Discussion Starter · #4 ·
Well the sound is getting louder over the last few days . Pleased in a way as dealer will be able to hear it clearly and hopefully find the cause .
 

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Yes its definitely a "characteristic" of the OM651 engine in either the A200d or A220d.
Ive had both, and they both make this noise. If anything its slightly worse in ECO mode.

I find its happiest on shell regular Diesel. The super diesel stuff does nothing for it.
And definitely dont put Asda Diesel in the tank as they run like crap on it.
 

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Discussion Starter · #7 ·
Well the car went in for it’s first service and as mentioned in answers to my post the dealer confirmed that it is a characteristic of this engine but if it gets any louder let them know . It doesn’t happen all the time but I am struggling to find any sort of pattern when the noise appears . It may be something pre and post DPF regeneration but cannot be sure .
On a positive note I did mention that I had a couple of rattles when going over bumps , I seriously expected that they would not be cured but the technician report stated that they had tightened a few areas but not exactly what . Anyway the rattles have gone so I suspect they had had other reports and knew where to look and resolve.
 

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Discussion Starter · #11 ·
I know this will temp fate but for a few days I have not heard the tiny rattle on acceleration . Also I have noticed that the exhaust is not popping as much after stopping . So , as we know the exhaust temperature has to be raised to turn the DPF soot content into ash . So my thoughts are it maybe the extra fuel injected to increase this temperature that is causing the tiny rattle . Be nice to hear if anyone else has the same thoughts .
 

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Discussion Starter · #12 ·
Well , the tiny rattle has returned louder than previously , must be something wrong as really don’t think it should sound like this . It happens every time you accelerate and stops once you take your foot of the pedal .
I know people are saying it’s a characteristic of the car but I just can’t believe it should sound like this for a premium brand car . I suppose another trip to the dealers coming up for me .
 

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Are you sure its not the oval exhaust tips rattling ?.
I had a loose one on mine, and it was making a right racket. Just had to bend some tabs on it so it fitted tighter. Problem solved.

Just put your hand on each exhaust tip (when cold), and give them a good wiggle and see what happens.
Obviously this is only on a FaceLift car. Sept 2015 onwards.
 

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Discussion Starter · #14 ·
I will certainly check this tomorrow . I think it must be exhaust related as only happens on acceleration and stops when just cruising . Thank You
 

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Discussion Starter · #15 ·
Definitely not the exhaust tips . Completed a 160 mile round trip today and the noise was continuous on every acceleration so know it’s not the DPF regeneration as has been suggested .
 

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I think you need to keep pestering your dealer about this one while the engine is still under warranty.

I do 800 miles a week in mine at the moment, and only get this sound very occasionally in Eco mode at light throttle when in slowish traffic.
I assume it has all the latest software updates ?.
 

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Can you advise what happened to the running of the cars when yours failed ?
When the exhaust flap fails, you get a check engine light and it goes into limp mode.
(Very slow laggy gear changes if auto), and 2000 max rpm.

My dealer said they get these alot with high mileage drivers like me. The unit gets so hot at higher rpm and the motor housing melts.
A terrible bit of design really. Putting a motor direct mount onto an exhaust pipe with the motor housing made of plastic. What did they think was going to happen......
 

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Discussion Starter · #18 ·
It had its first service at the dealers on the 4th June , I mentioned it but they said it’s normal which I find hard to believe . I assume they would carry out any updates during the service . Will see how it goes and return if it carries on . I get the feeling they try to blag you the first time as did say return if it gets worse . The sound is like a flap opening and closing tapping as it happens, this is why I have mentioned the exhaust flap as a possible culprit . My only other thought currently is a cylinder combustion issue . It will take time but I will get to the bottom of it eventually . Thanks for your reply .
 

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Discussion Starter · #19 ·
Well , the noise was really at its worst this evening . This is definitely not normal . Will be calling dealer tomorrow to get looked at . Luckily 2 years of warranty left . I don’t think they will be saying it’s a characteristic this time . It’s sounds absolutely awful .Wish me luck !!!
 

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Discussion Starter · #20 ·
Booked in on Thursday , will advise how it goes and hopefully what’s causing the noise and required remedy which won’t be turn the radio up ?
 
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