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      02-25-2015, 08:21 AM   #1
wings516
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Loud "pang" noise from exhaust on startup

Just recently started noticing this noise once the temp dropped below 32F.

On cold startup, about 5-20 seconds in there is a very loud metallic "PANG" or "TINK" noise coming from the exhaust area. Very audible from the interior and my coworker said it was loud as hell from the outside. It only happens once very shortly after startup, doesn't matter if it is in Drive, Park, or Reverse.

Anyone else having this issue or know what might be causing it?
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      02-25-2015, 08:28 AM   #2
nyalpine90
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im not sure if its same thing i experience, but i think the exhaust might be loose...it rattles on start up..

in my case there were 2 bolts missing, 1 loose bolt..
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      02-25-2015, 08:33 AM   #3
wings516
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Hm, I wish it was a rattle. The exhaust is very stable and clean sounding up until the pang noise, and then it is back to normal as soon as it does it and I won't hear it again until the next cold start. I'll double check for connections though.
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      02-25-2015, 09:00 AM   #4
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Could be the flap on the exhaust. It activates to speed you warming of the engine. Try golf tee mod by disconnecting the wire in the trunk left cubby hole after you lift up the cover.
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      02-25-2015, 09:01 AM   #5
nyalpine90
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are u still under warranty?
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      02-25-2015, 11:35 AM   #6
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Yeah, I get that noise relatively often when the exhaust is cold. Never had a chance to get it looked at.
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      02-25-2015, 02:59 PM   #7
lawfarm
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Quote:
Originally Posted by wings516 View Post
Just recently started noticing this noise once the temp dropped below 32F.

On cold startup, about 5-20 seconds in there is a very loud metallic "PANG" or "TINK" noise coming from the exhaust area. Very audible from the interior and my coworker said it was loud as hell from the outside. It only happens once very shortly after startup, doesn't matter if it is in Drive, Park, or Reverse.

Anyone else having this issue or know what might be causing it?
A poster below nailed it.

The X3 has a flap in the exhaust that closes under normal conditions, and opens under full throttle application to enhance exhaust flow. What you're hearing is that flap shutting shortly after engine startup, in cold weather. Totally normal.
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      02-25-2015, 06:07 PM   #8
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This is (unfortunately) normal. The exhaust flap freezes up, and when it opens on cold starts in really cold weather you sometimes (often) hear a loud clang or pang. The first time my wife's X3 made the noise I was alarmed, but it is completely normal.
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      02-26-2015, 09:26 AM   #9
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My X5's exhaust did the same thing, I always figured it was just something really quickly loosening back up as the metal expanded do to the quick warm up.

It definitely wasn't the flapper valve though, since I had the M Performance exhaust which doesn't have one.
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      02-26-2015, 02:36 PM   #10
lawfarm
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Quote:
Originally Posted by ND40oz View Post
My X5's exhaust did the same thing, I always figured it was just something really quickly loosening back up as the metal expanded do to the quick warm up.

It definitely wasn't the flapper valve though, since I had the M Performance exhaust which doesn't have one.
On the X3, if you stand outside it when it is cold and have someone start it, you can watch the change in the exhaust when the valve closes. It's the flapper valve.
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      02-26-2015, 04:20 PM   #11
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Quote:
Originally Posted by lawfarm View Post
On the X3, if you stand outside it when it is cold and have someone start it, you can watch the change in the exhaust when the valve closes. It's the flapper valve.
If the flapper valve was causing the noise, rather then thermal expansion, then you'd hear it every time the flapper valve opened and closed, not just when it's cold out. If your flapper valve is making noise as it operates, you'll probably want to have that looked at.
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      02-27-2015, 08:45 AM   #12
wings516
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Heh, another normal condition noise. And I just fixed my sunroof noise!

I'll WOT her a few times on the way home to see what happens, though it might be difficult to hear it over everything. I'll also try the flapper mod via cable disconnection.

Yep! Still another 62,000 miles on the warranty
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