Whining sound when AC on (video attached) Possible AC Compressor Clutch going bad?

mayno · 08-28-2017, 04:44 PM

have about 135K miles...had my serpentine belt replaced around 65K. anyway, I hear a whirring/squealing when RPMs go above 2500 to 3000 RPMs. if i put the car in neutral and rev, the whirring sound is still present and gets louder, the higher the RPM gets. any ideas on what this may be? how many belts does the e90 have? just the s-belt? or others? thanks.

Edit: discovered the sound only happens when the AC is on so it's definitely not the serpentine belt. any ideas on what it is? the AC is still very cold and runs great.

mayno · 08-29-2017, 10:20 AM

bump

BluesDriver · 08-29-2017, 02:19 PM

That sounds like a bearing going bad. Take off the belt and see if any of the pulleys are making noise or feel very loose.

mayno · 08-31-2017, 12:14 AM

so i isolated the sound. it only occurs when the AC is on. what could it be? the AC compressor, needs a recharge or something? the AC is still very cold. keep in mind, that i have had this car since 2007, and i leave the AC on "always" unless it's cold I use the heater, but that's like 2 months out of the entire year, i need the heater.

KentD · 08-31-2017, 05:49 AM

AC clutch slipping on engagement? Bad A/c compressor bearing?

mayno · 09-01-2017, 06:16 PM

i read on this forum that it could be the blower motor bearing... just don't know yet if that's the problem or if it's the AC compressor clutch.

it may be the AC compressor clutch since it gets louder with higher RPMs. the bearing in the Blower motor i don't think is RPM related.

zooch7 · 09-01-2017, 06:55 PM

AC whine can also be a slow leak/ running out of charge

mayno · 09-01-2017, 08:26 PM

but it's still very cold air. hard to associate a slow leak with the fact that it gets louder with the higher RPMs only.

cybermgm23 · 09-02-2017, 06:18 PM

could be a defective belt tensioner. as the ac engages it puts more strain on the belt thus causing is to slip if the tensioner is bad.

bobkat09 · 09-03-2017, 01:28 PM

Quote:

Originally Posted by zooch7

AC whine can also be a slow leak/ running out of charge

+1. Had similar noise. A/C needed recharging

siphor1989 · 09-04-2017, 07:08 PM

Quote:

Originally Posted by zooch7

AC whine can also be a slow leak/ running out of charge

When my ac was low on charge, the whine could only be heard in the cabin. The noise the OP has seems to be mechanical like a bad compressor bearing or clutch.

08-28-2017, 04:44 PM	#1
mayno Captain 72 Rep 613 Posts Drives: 2007 335i / 2018 BMW 430i Conv Join Date: Dec 2006 Location: So Cal iTrader: (0)	Whining sound when AC on (video attached) Possible AC Compressor Clutch going bad? have about 135K miles...had my serpentine belt replaced around 65K. anyway, I hear a whirring/squealing when RPMs go above 2500 to 3000 RPMs. if i put the car in neutral and rev, the whirring sound is still present and gets louder, the higher the RPM gets. any ideas on what this may be? how many belts does the e90 have? just the s-belt? or others? thanks. Edit: discovered the sound only happens when the AC is on so it's definitely not the serpentine belt. any ideas on what it is? the AC is still very cold and runs great. Last edited by mayno; 09-01-2017 at 08:27 PM.. Reason: added video
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08-29-2017, 10:20 AM	#2
mayno Captain 72 Rep 613 Posts Drives: 2007 335i / 2018 BMW 430i Conv Join Date: Dec 2006 Location: So Cal iTrader: (0)	bump
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08-29-2017, 02:19 PM	#3
BluesDriver Private 16 Rep 87 Posts Drives: 2011 328i Coupe Join Date: Nov 2011 Location: Los Angeles iTrader: (0)	That sounds like a bearing going bad. Take off the belt and see if any of the pulleys are making noise or feel very loose.
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08-31-2017, 12:14 AM	#4
mayno Captain 72 Rep 613 Posts Drives: 2007 335i / 2018 BMW 430i Conv Join Date: Dec 2006 Location: So Cal iTrader: (0)	so i isolated the sound. it only occurs when the AC is on. what could it be? the AC compressor, needs a recharge or something? the AC is still very cold. keep in mind, that i have had this car since 2007, and i leave the AC on "always" unless it's cold I use the heater, but that's like 2 months out of the entire year, i need the heater. Last edited by mayno; 08-31-2017 at 12:15 AM.. Reason: edit
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08-31-2017, 05:49 AM	#5
KentD New Member 4 Rep 9 Posts Drives: BMW E90 328i 2008 Sport Manual Join Date: Aug 2017 Location: Ottawa iTrader: (0)	AC clutch slipping on engagement? Bad A/c compressor bearing?
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09-01-2017, 06:16 PM	#6
mayno Captain 72 Rep 613 Posts Drives: 2007 335i / 2018 BMW 430i Conv Join Date: Dec 2006 Location: So Cal iTrader: (0)	i read on this forum that it could be the blower motor bearing... just don't know yet if that's the problem or if it's the AC compressor clutch. it may be the AC compressor clutch since it gets louder with higher RPMs. the bearing in the Blower motor i don't think is RPM related.
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09-01-2017, 06:55 PM	#7
zooch7 Private First Class 22 Rep 100 Posts Drives: 08 335i Join Date: Jun 2016 Location: Eugene, OR iTrader: (0)	AC whine can also be a slow leak/ running out of charge
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09-01-2017, 08:26 PM	#8
mayno Captain 72 Rep 613 Posts Drives: 2007 335i / 2018 BMW 430i Conv Join Date: Dec 2006 Location: So Cal iTrader: (0)	but it's still very cold air. hard to associate a slow leak with the fact that it gets louder with the higher RPMs only.
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09-02-2017, 06:18 PM	#9
cybermgm23 Second Lieutenant 54 Rep 297 Posts Drives: E90 328i, Jet Black Join Date: May 2016 Location: San Francisco iTrader: (0)	could be a defective belt tensioner. as the ac engages it puts more strain on the belt thus causing is to slip if the tensioner is bad.
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