this little sound clip is something maybe some of you have heard,,,,but maybe not,,,,this is a rattle noise coming from the exhaust system,,,,there is a metal spring clip that breaks and causes the metal flap inside the muffler tip to flap around and cause this rattling noise.
Here is the metal spring clip,,,,it is attached to a electric motor that opens and closes that flap inside the muffler tip,,,,and for some reason sometimes that metal spring clip breaks,,,,so we just put a new one back on and the noise goes away,,,,now some of you may have heard a rattle noise from your muffler tip during cold start,,,now that muffler flap is differs,,,that one is vacuum controlled and on that one,,,,the flap inside the muffler goes bad and rattles in the morning,,,,so to fix the vacuum controlled one,,,,we replace the rear muffler section.
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bmwtechnician 
i believe the 3 series is vacuum operated because I’ve indeed had that one go on me.
Is the 750 Li vacuum or electric?
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I believe it’s vacuum,,,,I would have have to check when I’m at work,,,,not 100% sure.
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This is some really good information about mufflers. I like that you explained that the rattling noise could be created because a spring clip has come loose. It seems like it would be smart to take your car into an auto shop if it is making any sort of odd noise.
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I’m glad I can help
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hi, Lately I Have Been Hearing this rattle coming from the exhaust
i checked the car in many places and no errors at all , engine is running perfect nothing is effected by this issue and you can hear it only when i’m revving and after driving it minimum 20 minutes so at cold start when i rev the engine i cant hear anything
it’s very wired cause when i’m revving the engine after 20 minutes of driving you can hear it
but if i wait 5 minutes the rattle goes away and on cold start everything is just perfect also when driving i never hear anything
i will be so glad if you can help on this
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Thanks for the video,,,,,,sounds like a exhaust rattle of a heat shield rattling,,,,,you need to lift up the car and have some one inside the car reving it while you are under the car looking for the rattle noise.
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thanks a lot man, i did so and they found that the rattle coming from the muffler (this silver box at the end of the car )
what could it be ? and why when i’m driving i don’t hear anything? only hear it after driving it directly and revv ? if i wait 5 minutes rattle is gone ?
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That metal box is to open and close the exhaust flap at certain times,,,,so you probably hear the rattle noise when the exhaust flap is at a certain position then is rattles.
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is it urgent to be done now as i’m really busy now and they need 4 days to check the exhaust system
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can i drive the car normally with this thing ?
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In my 2012 328i, the metal spring clip is missing (here is the part, if somebody is looking https://parts.bmwofsouthatlanta.com/products/Fixing-bow/10178580/18307620323.html) and I bought a new one. But the problem is I am unable to install it. The electric motor and the exhaust valve are never aligned and I even tried to loosen (by loosening 3 10 mm bolts) the motor to have more space, but still couldn’t. Would really appreciate any tips on how to install the spring clip.
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Lol,,,,,yes it kind of sucks,,,,there is a installation position the motor has to b put into so the spring clip can be installed,,,the only way to do that is with you hooked up to a diagnostic equipment.
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Really appreciate the prompt response! Can you tell me what diagnostic equipment I would need?
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Really appreciate the prompt response! Can you tell me what diagnostic equipment I would need?
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I only use the BMW diagnostic tool,,,,I’m sure some other diagnostic tool might work
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Hi can you please tell from where i can order it
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You can buy the muffler spring at the dealer
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What ?
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