metallic rattle on startup-then goes away (exhaust)

NORAGRETS · 10-02-2013, 06:47 AM

i have this kinda low frequency metallic rattle on cold starts only that seems to subside as soon as the engine revs drop to normal idle...

i tried taking a sound clip/video of it but it doesn't really come out that well so it would be useless to post...the exhaust completely drowns it out (straight pipes/catless, yaddah)

17,000 miles on the car...Berk axle back/berk mids/AR DP...never had any issues aside from midpipe knock on subframe...could this be it? rocks in exhaust? wastegate? loose bolts? (had them checked 2k miles ago) faulty hangar?

help!

jbertino · 10-02-2013, 07:20 AM

Quote:

Originally Posted by Twhill19

i have this kinda low frequency metallic rattle on cold starts only that seems to subside as soon as the engine revs drop to normal idle...

i tried taking a sound clip/video of it but it doesn't really come out that well so it would be useless to post...the exhaust completely drowns it out (straight pipes/catless, yaddah)

17,000 miles on the car...Berk axle back/berk mids/AR DP...never had any issues aside from midpipe knock on subframe...could this be it? rocks in exhaust? wastegate? loose bolts? (had them checked 2k miles ago) faulty hangar?

help!

Ive had the same thing for the last month . I think it is just waste gate rattling

BrewRifle · 10-02-2013, 08:25 AM

Most likely waste gate rattle. Mine does it as well.

RimasRS · 10-02-2013, 09:50 AM

My guess could be dual mass flywheel

marc@x-ph.com · 10-02-2013, 09:53 AM

I would have said that it could be your exhaust flap, but then you have an upgraded exhaust.

so yeah It's most probably your wastegates.

To be sure, try to recreate the noise after startup. slight tap on the throttle or may be rev to 3k, let the throttle go and wait for it.

NORAGRETS · 10-02-2013, 09:56 AM

Quote:

Originally Posted by marc@x-ph.com

I would have said that it could be your exhaust flap, but then you have an upgraded exhaust.

so yeah It's most probably your wastegates.

To be sure, try to recreate the noise after startup. slight tap on the throttle or may be rev to 3k, let the throttle go and wait for it.

Happens every cold start but to be honest the exhaust is so loud from 2.5k rpms I can't tell haha

Miko226 · 10-02-2013, 10:59 AM

I have the same as well it is Waste gate rattling might be getting close to the time to swap them out if it gets worse

jbertino · 10-02-2013, 11:05 AM

Quote:

Originally Posted by Miko226

I have the same as well it is Waste gate rattling might be getting close to the time to swap them out if it gets worse

Mine just started doing it. But my rattle isn't really noticeable whole driving

Miko226 · 10-02-2013, 12:49 PM

Quote:

Originally Posted by jbertino

Mine just started doing it. But my rattle isn't really noticeable whole driving

Yeah same here not very noticeable if at all while driving

MZWIE · 10-02-2013, 01:02 PM

Almost guaranty it is Waste Gate rattle. While stopped, rev engine and quickly release throttle. You will always hear rattle as RPM's decrease and excess pressure is released.

There is post in the E90 that shows how to adjust the rods in the WG to eliminte rattle. Hard to access, but doable.

NORAGRETS · 10-02-2013, 04:48 PM

Quote:

Originally Posted by e34m5

Almost guaranty it is Waste Gate rattle. While stopped, rev engine and quickly release throttle. You will always hear rattle as RPM's decrease and excess pressure is released.

There is post in the E90 that shows how to adjust the rods in the WG to eliminte rattle. Hard to access, but doable.

Thanks guys cars going in Monday to get checked out I'm not mechanically gifted enough to mess with myself I'll make it worse haha

NORAGRETS · 10-02-2013, 04:49 PM

17k is a little soon no?

NORAGRETS · 10-03-2013, 12:57 AM

100% wastes. Played with the throttle a lot in my garage in gear/neutral etc...sounds like quiet metallic fluttering...increases with rpm's...decreases as they fall. Doesn't 17,500 miles seem a little early for wastegates??

RimasRS · 10-03-2013, 02:40 AM

Quote:

Originally Posted by Twhill19

100% wastes. Played with the throttle a lot in my garage in gear/neutral etc...sounds like quiet metallic fluttering...increases with rpm's...decreases as they fall. Doesn't 17,500 miles seem a little early for wastegates??

Disconnect vacuum lines from two vacuum tanks and see if you still here it... You will discover that it is not wastegates...

NORAGRETS · 10-03-2013, 02:48 AM

Quote:

Originally Posted by RimasRS

Quote:

Originally Posted by Twhill19

100% wastes. Played with the throttle a lot in my garage in gear/neutral etc...sounds like quiet metallic fluttering...increases with rpm's...decreases as they fall. Doesn't 17,500 miles seem a little early for wastegates??

Disconnect vacuum lines from two vacuum tanks and see if you still here it... You will discover that it is not wastegates...

I'm clueless on wastes what do you think it is?

NORAGRETS · 10-03-2013, 02:49 AM

Quote:

Originally Posted by RimasRS

Quote:

Originally Posted by Twhill19

100% wastes. Played with the throttle a lot in my garage in gear/neutral etc...sounds like quiet metallic fluttering...increases with rpm's...decreases as they fall. Doesn't 17,500 miles seem a little early for wastegates??

Disconnect vacuum lines from two vacuum tanks and see if you still here it... You will discover that it is not wastegates...

Just loose vac lines?

yawn · 10-03-2013, 06:45 AM

Quote:

Originally Posted by Twhill19

Quote:

Originally Posted by RimasRS

Quote:

Originally Posted by Twhill19

100% wastes. Played with the throttle a lot in my garage in gear/neutral etc...sounds like quiet metallic fluttering...increases with rpm's...decreases as they fall. Doesn't 17,500 miles seem a little early for wastegates??

Disconnect vacuum lines from two vacuum tanks and see if you still here it... You will discover that it is not wastegates...

Just loose vac lines?

If you disconnect the vacuum lines and the sound disappears, most likely your wastegates. If there is no change, then most likely not your wastegates.

RimasRS · 10-03-2013, 07:14 AM

Quote:

Originally Posted by sharkatron

If you disconnect the vacuum lines and the sound disappears, most likely your wastegates. If there is no change, then most likely not your wastegates.

+1

lakylester · 10-04-2013, 08:06 PM

I agree with mostly everyone. I had the same issue. If you are decelerating in an enclosed space you can hear the rattle as well.

livnpaintball2 · 10-11-2013, 09:11 AM

He has a N55 not a N54.

10-02-2013, 06:47 AM	#1
NORAGRETS Colonel 442 Rep 2,046 Posts Drives: 2017 F80 M3 ZCP BSM 2012 E82 1 Join Date: May 2012 Location: Boston, MA iTrader: (0) Garage List 2017 BMW M3 ZCP LCI [0.00]	metallic rattle on startup-then goes away (exhaust) i have this kinda low frequency metallic rattle on cold starts only that seems to subside as soon as the engine revs drop to normal idle... i tried taking a sound clip/video of it but it doesn't really come out that well so it would be useless to post...the exhaust completely drowns it out (straight pipes/catless, yaddah) 17,000 miles on the car...Berk axle back/berk mids/AR DP...never had any issues aside from midpipe knock on subframe...could this be it? rocks in exhaust? wastegate? loose bolts? (had them checked 2k miles ago) faulty hangar? help! __________________ 2017 F80 ZCP BSM - Klein Innovation. ActiveAutowerkes. AR Design. BootMod3 Paul Johnson. EvRw. Project Gamma. RW Carbon. UCP. UUC. Hawk. Dinan. NGK. Macht Schnell. TMS. VR. aFe. RIP - E82 135i - 7/7/2021
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10-02-2013, 08:25 AM	#3
BrewRifle Lieutenant Colonel 420 Rep 1,678 Posts Drives: 2011 MCB E92 M3 Join Date: Jun 2013 Location: Austin, Texas iTrader: (4) Garage List 2011 BMW M3 [7.56] 2013 BMW X3 35i [0.00] 2009 BMW 135i [8.00]	Most likely waste gate rattle. Mine does it as well.
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10-02-2013, 09:50 AM	#4
RimasRS Colonel 85 Rep 2,438 Posts Drives: BMW X3 SD Join Date: Sep 2010 Location: Europe iTrader: (0)	My guess could be dual mass flywheel
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10-02-2013, 09:53 AM	#5
marc@x-ph.com Captain 15 Rep 678 Posts Drives: 2010 e92 335i Join Date: Sep 2013 Location: USA iTrader: (0)	I would have said that it could be your exhaust flap, but then you have an upgraded exhaust. so yeah It's most probably your wastegates. To be sure, try to recreate the noise after startup. slight tap on the throttle or may be rev to 3k, let the throttle go and wait for it.
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10-02-2013, 10:59 AM	#7
Miko226 Captain 61 Rep 722 Posts Drives: 11' 335d Join Date: Nov 2012 Location: Boca Raton, FL iTrader: (0)	I have the same as well it is Waste gate rattling might be getting close to the time to swap them out if it gets worse __________________ 11' m57 335d 165k Miles - JR 2, ATM Full Exhaust & Intake, Wagner FMIC, AAR Boost Pipe, AAR Swirl Delete, AAR EGR Delete 08' n54 135i FBO E85 - SOLD
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10-02-2013, 01:02 PM	#10
MZWIE Lieutenant Colonel 388 Rep 1,660 Posts Drives: M2 Join Date: Jun 2007 Location: GEORGIA iTrader: (0)	Almost guaranty it is Waste Gate rattle. While stopped, rev engine and quickly release throttle. You will always hear rattle as RPM's decrease and excess pressure is released. There is post in the E90 that shows how to adjust the rods in the WG to eliminte rattle. Hard to access, but doable.
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10-02-2013, 04:49 PM	#12
NORAGRETS Colonel 442 Rep 2,046 Posts Drives: 2017 F80 M3 ZCP BSM 2012 E82 1 Join Date: May 2012 Location: Boston, MA iTrader: (0) Garage List 2017 BMW M3 ZCP LCI [0.00]	17k is a little soon no? __________________ 2017 F80 ZCP BSM - Klein Innovation. ActiveAutowerkes. AR Design. BootMod3 Paul Johnson. EvRw. Project Gamma. RW Carbon. UCP. UUC. Hawk. Dinan. NGK. Macht Schnell. TMS. VR. aFe. RIP - E82 135i - 7/7/2021
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10-03-2013, 12:57 AM	#13
NORAGRETS Colonel 442 Rep 2,046 Posts Drives: 2017 F80 M3 ZCP BSM 2012 E82 1 Join Date: May 2012 Location: Boston, MA iTrader: (0) Garage List 2017 BMW M3 ZCP LCI [0.00]	100% wastes. Played with the throttle a lot in my garage in gear/neutral etc...sounds like quiet metallic fluttering...increases with rpm's...decreases as they fall. Doesn't 17,500 miles seem a little early for wastegates?? __________________ 2017 F80 ZCP BSM - Klein Innovation. ActiveAutowerkes. AR Design. BootMod3 Paul Johnson. EvRw. Project Gamma. RW Carbon. UCP. UUC. Hawk. Dinan. NGK. Macht Schnell. TMS. VR. aFe. RIP - E82 135i - 7/7/2021
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10-04-2013, 08:06 PM	#19
lakylester Private First Class 11 Rep 130 Posts Drives: 135i, A4 Join Date: Sep 2011 Location: nj iTrader: (0)	I agree with mostly everyone. I had the same issue. If you are decelerating in an enclosed space you can hear the rattle as well.
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10-11-2013, 09:11 AM	#20
livnpaintball2 Second Lieutenant 36 Rep 260 Posts Drives: E82 N54 Join Date: Mar 2013 Location: Dfw iTrader: (0)	He has a N55 not a N54.
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