matteoflaim

I just bought a 2019 c43 amg with 45000 km on it, pretty well maintained car.

When i start the car there is a rattling noise underneath the car (i’m thinking it’s my heat shield) is this a common problem or has anyone had this before. Thanks

MJ50

moved to W205 AMG forum...

C43HeartBoost

Not a common problem that I am aware of (separate and distinct from the interior creeks that permeate the w205 platform). Does the problem get better or go away when the car warms up? When rattling, does it get better or worse with RPM? Can you tell if it is from the lower front, middle or back of the car?

matteoflaim

When the car warms up it gets quieter aswell as when the rpm’s are dropping when starting it gets quieter, i cannot here it when i drive or go thru high rpm’s as the exhaust is quite loud. I’d also say it would be in the middle to back area baby

C43HeartBoost

Do you have the “performance exhaust” - the one with the button to open and close valves? If so, it could be a valve issue. Due to the fact that it gets better when warm, I doubt it is a heat shield issue (from a root cause standpoint). Your goal should be pinpointing the general area where the sound is coming from (perhaps have someone else start your car when cold, while you are outside the car).

W205C43PFL

Perhaps record the sound for us to listen as well if it picks up.

matteoflaim

Ahyes i do, if so would that be a big issue? I am not to great with cars this is my first performance car if you could say.



I will do that to get a better pinpoint tomorrow aswell as take a video and send it with the sound, thanks a lot.

Hungalow

Op.....if you are new to our. platform, injectors are very loud and ticky upon starup, even worse if started in a garage. Plus the slight delay for the oil to reach upper engine parts when cold. As long as sound goes away or is acceptable when hot and does not get worse or louder. Should be good.

4npower

It's the turbo wastegate flapper doors. These cars cold start with the wastegates open until the vacuum pump builds enough pressure to close them(usually less than 30 seconds), so the flappers will rattle until they are seated/pulled shut. This is also why these cars are so loud for the first 30ish seconds and then "calm" down.

W205C43PFL

This is most likely it therefore it could be normal.

matteoflaim

hey guys, thanks for the help again, i took a video of the sound to show, let me know what you guys think.

W205C43PFL

Hmmm strange I don't hear anything abnormal what timestamp is the sound at?

4npower

Yep, sounds good and normal👍

matteoflaim

[QUOTE=W205C43PFL;8807353]Hmmm strange I don't hear anything abnormal what timestamp is the sound at?


it’s from about 5 seconds to 8 seconds in the video, it’s almost just a faint rattle that you hear come on then starts to get quieter as rpm falls towards end of vid. you will hear the car start and about 1-2 seconds after that the sound comes on.

Seems like not a big issue, car runs smoothly was just more so curious.

W205C43PFL

[QUOTE=matteoflaim;8807472]Ya so I don't hear anything abnormal from your video, I initially thought your device didn't pick up the sound but then you said you can hear it at 5 seconds to 8 seconds and from what I hear, nothing out of the ordinary. Enjoy your car as it doesn't seem like there is anything wrong with it.

W205C43PFL

If you are still concerned however, maybe try filming the video from the engine bay although the injectors might overwhelm the sound you might be referring to.