Whirring Fan Sound When Braking

jclaib7 · 02-13-2016, 07:49 PM

Any idea what this is? It's whirring fan sound when i'm braking. It stops when the vehicle comes to a halt. It only happens when braking. When I turn off the fan the sound goes away.

???

FactorX81 · 02-14-2016, 12:09 PM

I have the same noise braking and turning left. I did a search and found that the blower motor bearing tends to rust and needs to be cleaned and lubed to get rid of the problem.

Horigan · 02-14-2016, 07:55 PM

You can access the blower shaft by removing the cabin filter under the hood and maybe getting access to the blower shaft to spray it with lubricant, though your cabin will smell like it for a while. I just replaced the blower as I know the noise will return. BMW made it relatively easy to replace after you remove the glove box. See Pelican parts for videos on E90s that are applicable.

Suhb · 02-15-2016, 04:10 PM

Moisture gets in and rusts the bearing as someone pointed out. I had mine replaced under warranty and warned the service department that it would come back if the moisture leak persists. Sure enough, 2 years after the replacement, the noise it back and I'm out of warranty. I guess I'll be opening it up to lube it.

jclaib7 · 02-18-2016, 05:05 PM

Why would applying break pressure make this louder?

Suhb · 02-19-2016, 04:18 PM

No idea. But the sound worsened for me too under braking and turns. Quieted down at a full stop.

Horigan · 02-21-2016, 08:13 PM

The mild side loads during braking and turning make the rusty bearing get louder.

02-13-2016, 07:49 PM	#1
jclaib7 First Lieutenant 142 Rep 324 Posts Drives: 2018 M2 Black Shadow Edition Join Date: Jul 2013 Location: United States, Beverly Ma. iTrader: (2)	Whirring Fan Sound When Braking Any idea what this is? It's whirring fan sound when i'm braking. It stops when the vehicle comes to a halt. It only happens when braking. When I turn off the fan the sound goes away. ??? __________________ 2018 M2 Black Shadow Edition
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02-14-2016, 12:09 PM	#2
FactorX81 First Lieutenant 29 Rep 363 Posts Drives: 2010 135i, 2014 Ford Escape Ti Join Date: Nov 2009 Location: NJ iTrader: (0)	I have the same noise braking and turning left. I did a search and found that the blower motor bearing tends to rust and needs to be cleaned and lubed to get rid of the problem.
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02-14-2016, 07:55 PM	#3
Horigan Private First Class 23 Rep 110 Posts Drives: 2011 135i M-Sport Join Date: May 2013 Location: Seattle WA, USA iTrader: (0)	You can access the blower shaft by removing the cabin filter under the hood and maybe getting access to the blower shaft to spray it with lubricant, though your cabin will smell like it for a while. I just replaced the blower as I know the noise will return. BMW made it relatively easy to replace after you remove the glove box. See Pelican parts for videos on E90s that are applicable.
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02-15-2016, 04:10 PM	#4
Suhb First Lieutenant 119 Rep 377 Posts Drives: 2010 128i Coupe 6-Speed Join Date: Dec 2012 Location: PA iTrader: (3)	Moisture gets in and rusts the bearing as someone pointed out. I had mine replaced under warranty and warned the service department that it would come back if the moisture leak persists. Sure enough, 2 years after the replacement, the noise it back and I'm out of warranty. I guess I'll be opening it up to lube it.
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02-18-2016, 05:05 PM	#5
jclaib7 First Lieutenant 142 Rep 324 Posts Drives: 2018 M2 Black Shadow Edition Join Date: Jul 2013 Location: United States, Beverly Ma. iTrader: (2)	Why would applying break pressure make this louder? __________________ 2018 M2 Black Shadow Edition
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02-19-2016, 04:18 PM	#6
Suhb First Lieutenant 119 Rep 377 Posts Drives: 2010 128i Coupe 6-Speed Join Date: Dec 2012 Location: PA iTrader: (3)	No idea. But the sound worsened for me too under braking and turns. Quieted down at a full stop.
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02-21-2016, 08:13 PM	#7
Horigan Private First Class 23 Rep 110 Posts Drives: 2011 135i M-Sport Join Date: May 2013 Location: Seattle WA, USA iTrader: (0)	The mild side loads during braking and turning make the rusty bearing get louder.
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