drive belt replaced, new one is now squealing

Cmjameson · 07-16-2019, 04:28 PM

had my car in the shop last week(2010 335i, n54), mechanic noticed my drive belt was worn so he replaced it. the next day my new belt was squealing which had never happened before, I brought it back to him and he just put lubricant on it, sound gone. he told me it just needs to break in. now a week later after a long drive my belt is squealing again. should I just go to auto zone and buy lubricant to put on it or should I bring it to a different mechanic and just get it replaced? this noise just started from my new belt so I believe the pulleys and bearings are all fine and its the belt specifically. could the belt have been installed wrong/misaligned or be the wrong type? I checked ofhg for leaks and looked for oil on the belt but its all dry, everything appears fine.

Tambohamilton · 07-16-2019, 05:14 PM

First, don't lubricate the belt! You can get spray stuff that helps them grip, but it's a temporary bodge.

If the new belt is good, which it probably is (because it presumably fits correctly), one or more of the pulleys is probably bad. Or the tensioner. Or the crank vibration dampener is about to disintegrate.

My dilemma would be, do you take it back to the mechanic who fobbed you off with the anti-slip nonsense, or do you pay someone else to sort out his mess?

Good luck with it either way!

e90yyc · 07-16-2019, 05:32 PM

Quote:

Originally Posted by Cmjameson

had my car in the shop last week(2010 335i, n54), mechanic noticed my drive belt was worn so he replaced it. the next day my new belt was squealing which had never happened before, I brought it back to him and he just put lubricant on it, sound gone. he told me it just needs to break in. now a week later after a long drive my belt is squealing again. should I just go to auto zone and buy lubricant to put on it or should I bring it to a different mechanic and just get it replaced? this noise just started from my new belt so I believe the pulleys and bearings are all fine and its the belt specifically. could the belt have been installed wrong/misaligned or be the wrong type? I checked ofhg for leaks and looked for oil on the belt but its all dry, everything appears fine.

Lubricating a belt is some bush league bull isht. I suppose next thing he’s gonna tell you is the belt is slipping and needs to be replaced

. I’ve also never heard of “breaking in” a belt. I’ve replaced mine once. Quiet from day one.

Cmjameson · 07-16-2019, 05:42 PM

ok ill take it to a more reputable shop, I used a kind of dumpy indy shop because their two blocks away and I didn't think simple things like this could be messed up. Im having a hard time believing the pulleys were bad because its ran seamlessly until the new belt was put on, do you think this job being botched could have damaged anything?

Tambohamilton · 07-16-2019, 06:04 PM

No, I doubt it will have caused any damage. May need to clean whatever the last shop used to stop the squeak off the pulleys. That said, they did manage to botch a belt replacement...

Explorerlyon · 07-16-2019, 08:43 PM

Belt slippage squeal usually only happens under acceleration then stops. If you have noise at idle or while steady smooth cruising, it's likely a pully. Replace the tensioner if it was not replaced with the belt.

nsjames · 07-16-2019, 08:48 PM

I'd be willing to bet he sprayed some lube at the backside of one of the tensioners and it was quiet for a week.

do not neglect this. broken belts kill n5x engines.

it's worth it to buy the complete kit.
This is an excellent opportunity to save some money, as it's a very easy DIY to do the belt and pulleys with minimal hand tools.

mweisdorfer · 07-17-2019, 07:24 AM

DO NOT use belt dressing. Something is a miss here.

I'd buy a kit from FCP Euro and take it to a reputable place that specializes in European Auto's and have them use your kit to replace the belt & pulleys etc.

charlieb · 07-17-2019, 08:00 AM

More than likely pulley (bearings) are worn out.
The last belt was stretched enough to not put as much pressure on the pulleys. The new belts is shorter putting more pressure on the bearings which is more than likely where the noise is coming from.

Wolf 335 · 07-17-2019, 08:08 AM

Quote:

Originally Posted by Cmjameson

had my car in the shop last week(2010 335i, n54), mechanic noticed my drive belt was worn so he replaced it. the next day my new belt was squealing which had never happened before, I brought it back to him and he just put lubricant on it, sound gone. he told me it just needs to break in. now a week later after a long drive my belt is squealing again. should I just go to auto zone and buy lubricant to put on it or should I bring it to a different mechanic and just get it replaced? this noise just started from my new belt so I believe the pulleys and bearings are all fine and its the belt specifically. could the belt have been installed wrong/misaligned or be the wrong type? I checked ofhg for leaks and looked for oil on the belt but its all dry, everything appears fine.

Which belt brand and part number did they use on your car?

Try to locate the writing on the belt, should say CONTITECH 7PK 1860

07-16-2019, 04:28 PM	#1
Cmjameson New Member 0 Rep 7 Posts Drives: 2010 335xi Join Date: Jul 2019 Location: Long island iTrader: (0)	drive belt replaced, new one is now squealing had my car in the shop last week(2010 335i, n54), mechanic noticed my drive belt was worn so he replaced it. the next day my new belt was squealing which had never happened before, I brought it back to him and he just put lubricant on it, sound gone. he told me it just needs to break in. now a week later after a long drive my belt is squealing again. should I just go to auto zone and buy lubricant to put on it or should I bring it to a different mechanic and just get it replaced? this noise just started from my new belt so I believe the pulleys and bearings are all fine and its the belt specifically. could the belt have been installed wrong/misaligned or be the wrong type? I checked ofhg for leaks and looked for oil on the belt but its all dry, everything appears fine.
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07-16-2019, 05:14 PM	#2
Tambohamilton Brigadier General 3058 Rep 3,910 Posts Drives: E91 330d Join Date: Apr 2019 Location: Herefordshire iTrader: (0)	First, don't lubricate the belt! You can get spray stuff that helps them grip, but it's a temporary bodge. If the new belt is good, which it probably is (because it presumably fits correctly), one or more of the pulleys is probably bad. Or the tensioner. Or the crank vibration dampener is about to disintegrate. My dilemma would be, do you take it back to the mechanic who fobbed you off with the anti-slip nonsense, or do you pay someone else to sort out his mess? Good luck with it either way!
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07-16-2019, 05:42 PM	#4
Cmjameson New Member 0 Rep 7 Posts Drives: 2010 335xi Join Date: Jul 2019 Location: Long island iTrader: (0)	ok ill take it to a more reputable shop, I used a kind of dumpy indy shop because their two blocks away and I didn't think simple things like this could be messed up. Im having a hard time believing the pulleys were bad because its ran seamlessly until the new belt was put on, do you think this job being botched could have damaged anything?
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07-16-2019, 06:04 PM	#5
Tambohamilton Brigadier General 3058 Rep 3,910 Posts Drives: E91 330d Join Date: Apr 2019 Location: Herefordshire iTrader: (0)	No, I doubt it will have caused any damage. May need to clean whatever the last shop used to stop the squeak off the pulleys. That said, they did manage to botch a belt replacement...
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07-16-2019, 08:43 PM	#6
Explorerlyon Private First Class 108 Rep 148 Posts Drives: Porsche 986 Acura TL-SHAWD BMW Join Date: May 2019 Location: USA iTrader: (0) Garage List 2007 E90 335xi [0.00] 2006 E90 330i [0.00] 2012 Acura TL SH-AWD [0.00] 2001 Porsche 986 [0.00]	Belt slippage squeal usually only happens under acceleration then stops. If you have noise at idle or while steady smooth cruising, it's likely a pully. Replace the tensioner if it was not replaced with the belt.
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07-16-2019, 08:48 PM	#7
nsjames Brigadier General 2440 Rep 4,330 Posts Drives: 08 328xi Touring Join Date: May 2017 Location: ohio iTrader: (0)	I'd be willing to bet he sprayed some lube at the backside of one of the tensioners and it was quiet for a week. do not neglect this. broken belts kill n5x engines. it's worth it to buy the complete kit. This is an excellent opportunity to save some money, as it's a very easy DIY to do the belt and pulleys with minimal hand tools.
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07-17-2019, 07:24 AM	#8
mweisdorfer Major General 1903 Rep 6,968 Posts Drives: 2007 Black/Black 335i e90 Join Date: Apr 2011 Location: Holly, MI iTrader: (0) Garage List 2007 BMW E90 335i [0.00] 2008 bmw x5 [0.00]	DO NOT use belt dressing. Something is a miss here. I'd buy a kit from FCP Euro and take it to a reputable place that specializes in European Auto's and have them use your kit to replace the belt & pulleys etc.
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07-17-2019, 08:00 AM	#9
charlieb Enlisted Member 21 Rep 41 Posts Drives: 2007 328i Manual Join Date: Jun 2019 Location: New York iTrader: (0)	More than likely pulley (bearings) are worn out. The last belt was stretched enough to not put as much pressure on the pulleys. The new belts is shorter putting more pressure on the bearings which is more than likely where the noise is coming from.
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