Noise from rear of car when hitting bumps

romnation · 11-17-2020, 03:09 PM

I'm getting a very slight knock noise from the rear of the car when hitting bumps. Its quiet, but you can hear it with the radio completely off. Mileage is 60k. Doesn't seem to be anything inside the car causing the issue. What could this possibly be? All of my suspension components are original. I'm wondering if it could possibly be shocks / struts but I don't want to jump to any conclusions. Any ideas?

tracer bullet · 11-17-2020, 04:02 PM

In my experience with other cars it's always a worn strut. No gas pressure inside, and the shaft rattles a bit at times.

iamroddy · 11-17-2020, 05:13 PM

Worn swaybar links can also cause same/similar noises.

Lester · 11-17-2020, 06:37 PM

Have it inspected at a dealer or local oem/performance shop. If there is anything there to worry about, you will have a good idea about the scope and cost to repair.

jdt10768 · 11-23-2020, 11:55 AM

remove dead body from trunk, repeat test

dtla1 · 11-23-2020, 12:31 PM

Could also just be work strut mount, especially the top mount is a spongy type of foam materials.

Thunderguts · 11-25-2020, 05:22 PM

Quote:

Originally Posted by iamroddy

Worn swaybar links can also cause same/similar noises.

Can confirm. I replaced my sway bar and forgot to torque down one side and it made a slight knocking sound on bumps. I'm sure a worn link would do the same.

Thunderguts · 11-25-2020, 05:24 PM

Quote:

Originally Posted by jdt10768

remove dead body from trunk, repeat test

The dead ones are completely silent. They only make noise when they struggle.

11-17-2020, 03:09 PM	#1
romnation Private 18 Rep 69 Posts Drives: 135i Join Date: Jul 2016 Location: Chicago iTrader: (0)	Noise from rear of car when hitting bumps I'm getting a very slight knock noise from the rear of the car when hitting bumps. Its quiet, but you can hear it with the radio completely off. Mileage is 60k. Doesn't seem to be anything inside the car causing the issue. What could this possibly be? All of my suspension components are original. I'm wondering if it could possibly be shocks / struts but I don't want to jump to any conclusions. Any ideas?
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11-17-2020, 04:02 PM	#2
tracer bullet Brigadier General 2410 Rep 3,545 Posts Drives: '11 135i , '15 X3 35i Join Date: May 2011 Location: Saint Paul, MN iTrader: (1)	In my experience with other cars it's always a worn strut. No gas pressure inside, and the shaft rattles a bit at times.
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11-17-2020, 05:13 PM	#3
iamroddy Private First Class 86 Rep 117 Posts Drives: 128i Join Date: Sep 2020 Location: 613 iTrader: (0)	Worn swaybar links can also cause same/similar noises.
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11-17-2020, 06:37 PM	#4
Lester Brigadier General 295 Rep 3,350 Posts Drives: Join Date: Oct 2007 iTrader: (0)	Have it inspected at a dealer or local oem/performance shop. If there is anything there to worry about, you will have a good idea about the scope and cost to repair. __________________ 2008 135i, Jet Black, 6 spd, Canadian Sport package, black leatherette, manual seats, aluminum glacier trim, PDC. 1983 E21 Delphin, M10, 5 speed, LSD, MSW wheels, recaro seats, Hartge strut brace, rear sway bar. [SIGPIC][/SIGPIC]
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11-23-2020, 11:55 AM	#5
jdt10768 Lieutenant 330 Rep 529 Posts Drives: 2013 128i MSport 6MT Join Date: Sep 2018 Location: Columbia, SC iTrader: (0)	remove dead body from trunk, repeat test
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11-23-2020, 12:31 PM	#6
dtla1 Colonel 828 Rep 2,232 Posts Drives: 2011 135i, Space Grey Join Date: Apr 2014 Location: Silicon Valley iTrader: (2)	Could also just be work strut mount, especially the top mount is a spongy type of foam materials.
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