My $600+ (and counting) belt squeak odyssey...

AndyW · 03-20-2019, 11:00 PM

2012 135i N55.

So, over the past two months or so I have been trying to find what is causing my belt/pulley squeak noises on cold start until about 5 min of run time. Very annoying problem!

First, I have verified I do not have an OFHG leak (common cause). This squeak started back right after replacing the belt, so it's not oil leakage.

Also, it is not a PCV issue. Sound does not change when I open the oil cap.

My troubleshooting methods via water spray, stethoscope, and tube listening have been abject failures as whatever is causing this is likely causing the tensioner to oscillate, making IT make the noise, but it is not the source. I have been "90% sure" each time I have replaced something new, but still no joy.

Here is what I have replaced thus far.

- Tensioner and pulleys. Twice. Yes, twice. Now I have a spare set. Yay me. So I guess i am good in that department for the next 150K or so...Sound did get better after the second replacement - see videos below.

- Belt. Only the one time. Tempted to get another one, just to be sure...

- P/S pump. Only once.

- I just ordered a used Alternator for $100 on ebay that has a 30 day return policy.

Every time I have replaced something it seems to get better for a minute or so and then come back. I also can see the Tensioner vibrating a bit.

I have verified all the pulley torques are correct.

I really hope it is the Alternator(can you just replace the bearing?) New Alternator is $400.

The only two things left to replace if the Alternator doesn't work are the A/C compressor (but there is no change in the squealing/chirping when I disengage the A/C) and the Harmonic balancer (it doesn't look like it is wobbling very much). Both of those are pretty pricey parts.

Related: Anyone know why the Bentley manual wants some kind of special tools to lock the flywheel for N55 manual and automatic transmissions for replacing the harmonic balancer? I have a DCT so I am not even sure if this applicable and the N54 version requires no special tools. It's not like the thing is keyed in either case. Seems to me the only thing it might be preventing is rolling the crank in reverse (I assume reverse is CCW?).

TIA for any collective wisdom that can be provided...this is really driving me nuts!

Here is a video after replacing the belt, tensioner, both pullies and the P/S Pump.

Here is the sound (reduced to a chirp now) after replacing the Tensioner and both pullies, again. I replaced them one at a time and it seemed to reduce the most when replacing the larger idler pulley. Again, this was the second time for all.

Of note, when I replaced the P/S pump (long story why I replaced that first), it reduced to a chirp as well, then came back to the levels in the first video. When I replaced the belt/tensioner/pullies, it got a little better, then back to first video levels. I fully expect it will be back to the first video levels in a week. Granted, it was a lot colder when I did the initial replacements (in the 30's). Now it is in the 40's and 50's in the AM so that could be "helping".

Mybimmer · 03-21-2019, 06:22 AM

Trying another belt would have been the cheaper and first thing to rule out. You're gonna kick yourself if it's the belt dude.

AndyW · 03-21-2019, 07:42 AM

Quote:

Originally Posted by Mybimmer

Trying another belt would have been the cheaper and first thing to rule out. You're gonna kick yourself if it's the belt dude.

Well, I did replace it once...

tracer bullet · 03-21-2019, 08:07 AM

OEM belt? Even if it is, any chance it's not the correct width or something?

Wish I had a better idea, really interested in how you solve this. Mine only squeaks for 1/2 - 1 second after startup but I read these threads and wonder what will happen next and if there's a tried & proven solution.

Gizmo135i · 03-21-2019, 09:24 AM

Are you sure it’s the belt? It’s pretty common for the PCV valve to make a noise like that. The way to test it is to remove the oil filler cap while the noise is happening, if it goes away it means there is too much vacuum inside the crankcase which causes air to leak past the front or rear crankshaft seal and make a squealing noise.

Another thing that could cause that noise is the oil filter, if you have an aftermarket one installed you might want to change it with an oem filter and bmw oil. Variations in oil pressure could cause vanos timing to be off which could cause the same noise.

Also make sure the stem is still installed in the oil filter cap, sometimes it comes out with the filter and people throw it out.

Hope that helps!

AndyW · 03-21-2019, 11:43 PM

Quote:

Originally Posted by Gizmo135i

Are you sure it’s the belt? It’s pretty common for the PCV valve to make a noise like that. The way to test it is to remove the oil filler cap while the noise is happening, if it goes away it means there is too much vacuum inside the crankcase which causes air to leak past the front or rear crankshaft seal and make a squealing noise.

Another thing that could cause that noise is the oil filter, if you have an aftermarket one installed you might want to change it with an oem filter and bmw oil. Variations in oil pressure could cause vanos timing to be off which could cause the same noise.

Also make sure the stem is still installed in the oil filter cap, sometimes it comes out with the filter and people throw it out.

Hope that helps!

Good points. I did check the PCV vacuum thing early on after reading a thread when the problem first appeared. I'll open the oil cap again in the AM at cold start just to be sure. 99% sure this sound is not the PCV. I'll be posting a video shortly of the sound.

Never heard of the oil filter issue, but I change my own oil and have never had an issue or thrown that part away. Filter is OEM and oil is LiquiMoly...been using that for years on my BMW's with no issues. Thx for the suggestion tho'.

HyeWarrior · 03-22-2019, 03:23 AM

Lol sub'd

I have a very very similar sound and maintenance history. I was convinced it's my alternator too, but I've been lazy to tackle the project. Interested to see if it resolves for you!

AndyW · 03-22-2019, 07:53 AM

Quote:

Originally Posted by tracer bullet

OEM belt? Even if it is, any chance it's not the correct width or something?

Wish I had a better idea, really interested in how you solve this. Mine only squeaks for 1/2 - 1 second after startup but I read these threads and wonder what will happen next and if there's a tried & proven solution.

It's a gates but it is the correct width.

tracer bullet · 03-22-2019, 08:01 AM

Quote:

Originally Posted by AndyW

It's a gates but it is the correct width.

There are some spray-on belt dressings. I wouldn't think of that as a sway to actually solve this, but might be a temporary thing to see if it suddenly makes the noise go away... sort of a means to help decide on a next direction.

OkieSnuffBox · 03-22-2019, 08:28 AM

I swear I have the same thing at startup, or if the idle dips low, but my Indy guy has assured the tensioner and everything are fine.

MightyMouseTech · 03-22-2019, 11:45 AM

Best way I know to test if it's the belt is to put a bit of talc (baby powder) on the belt. If there is any oil contamination on the belt, the talc will absorb the oil and provide grip.

Usually the noise will go away instantly.

SoFloE82 · 03-23-2019, 04:26 PM

I had a the same sound which turned out to be a oil filter housing leak. The oil was leaking onto the belts causing a squeak. I know you replaced the belts and the noise remained so I doubt this is the issue but take a look. If you've spent some time under the hood, I'd think you would have caught it by now, but just take a second look at the valve cover. Make sure you dont have a small leak anywhere. I'm at 60K and I've had bother an oil filer housing leak and a valve cover gasket leak already. Good luck!

chrisw27 · 03-26-2019, 05:12 PM

Hi Andy, i am also interested in this, as i have what seems to be the same noise. It happens when the engine is fully up to temp, and even then only after spirited driving. It definitely came on after that bloody OFHG leak. So far i have only cleaned the belt and pulleys, next step is to replace them all.

Re the alternator, i believe changing both bearings - front and back - is possible. They are designed to be serviceable, and i have done this on my wife's e46. I have not seen a DIY for an n5x though...i would personally attempt this before paying $$$ for a replacement.

AndyW · 03-26-2019, 10:13 PM

Quote:

Originally Posted by SoFloE82

I had a the same sound which turned out to be a oil filter housing leak. The oil was leaking onto the belts causing a squeak. I know you replaced the belts and the noise remained so I doubt this is the issue but take a look. If you've spent some time under the hood, I'd think you would have caught it by now, but just take a second look at the valve cover. Make sure you dont have a small leak anywhere. I'm at 60K and I've had bother an oil filer housing leak and a valve cover gasket leak already. Good luck!

I've looked multiple times and had the OFHG leak on my 335i N54 (and fixed it). At this point I'd be happy to have an OFHG leak be the cause!

AndyW · 03-26-2019, 10:14 PM

Quote:

Originally Posted by chrisw27

Hi Andy, i am also interested in this, as i have what seems to be the same noise. It happens when the engine is fully up to temp, and even then only after spirited driving. It definitely came on after that bloody OFHG leak. So far i have only cleaned the belt and pulleys, next step is to replace them all.

Re the alternator, i believe changing both bearings - front and back - is possible. They are designed to be serviceable, and i have done this on my wife's e46. I have not seen a DIY for an n5x though...i would personally attempt this before paying $$$ for a replacement.

Everywhere I've looked it seems like you have to buy the whole alternator unit. If the $100 one fixes the problem, I'll look at redoing the bearings on the one I remove, tho, if I can get the parts.

AndyW · 03-26-2019, 10:38 PM

Found this...https://www.maniacelectricmotors.com...042106052.html

AndyW · 03-26-2019, 10:48 PM

On a related note from looking at several DIYs...you really have to remove the OFHG to remove the Alternator? Kinda ridiculous IMO.

thibb001 · 03-27-2019, 11:06 AM

I would try replacing with OEM belt. I had the same squeak a few weeks ago and it turns out i gota little bit of oil on my belt after changing out my oil filter housing gasket. I couldn't see oil on the belt but as soon as i changed it no squeak.

dtla1 · 03-27-2019, 06:32 PM

Any other Oil Leaks around the car? Like Rear Main Seal, or the Oil Pan Gasket itself? Your test for releasing the pressure on the PCV by opening the filler would prob make it go away, but a tiny leak somewhere could cause a whistle like this.

Mybimmer · 03-27-2019, 08:48 PM

Also check belt direction. Some have a rotation direction shown by arrows on the belt.

AndyW · 03-27-2019, 08:56 PM

Quote:

Originally Posted by dtla1

Any other Oil Leaks around the car? Like Rear Main Seal, or the Oil Pan Gasket itself? Your test for releasing the pressure on the PCV by opening the filler would prob make it go away, but a tiny leak somewhere could cause a whistle like this.

Thx. No other leaks.

AndyW · 03-27-2019, 08:57 PM

Quote:

Originally Posted by Mybimmer

Also check belt direction. Some have a rotation direction shown by arrows on the belt.

I don't recall the belt being directional, but I'll check it!

03-20-2019, 11:00 PM	#1
AndyW Supreme Galactic Commander (one galaxy over...) 667 Rep 1,777 Posts Drives: '08 E93, '12 E82, '13 E93 M3 Join Date: Feb 2012 Location: Washington, USA iTrader: (5)	My $600+ (and counting) belt squeak odyssey... 2012 135i N55. So, over the past two months or so I have been trying to find what is causing my belt/pulley squeak noises on cold start until about 5 min of run time. Very annoying problem! First, I have verified I do not have an OFHG leak (common cause). This squeak started back right after replacing the belt, so it's not oil leakage. Also, it is not a PCV issue. Sound does not change when I open the oil cap. My troubleshooting methods via water spray, stethoscope, and tube listening have been abject failures as whatever is causing this is likely causing the tensioner to oscillate, making IT make the noise, but it is not the source. I have been "90% sure" each time I have replaced something new, but still no joy. Here is what I have replaced thus far. - Tensioner and pulleys. Twice. Yes, twice. Now I have a spare set. Yay me. So I guess i am good in that department for the next 150K or so...Sound did get better after the second replacement - see videos below. - Belt. Only the one time. Tempted to get another one, just to be sure... - P/S pump. Only once. - I just ordered a used Alternator for $100 on ebay that has a 30 day return policy. Every time I have replaced something it seems to get better for a minute or so and then come back. I also can see the Tensioner vibrating a bit. I have verified all the pulley torques are correct. I really hope it is the Alternator(can you just replace the bearing?) New Alternator is $400. The only two things left to replace if the Alternator doesn't work are the A/C compressor (but there is no change in the squealing/chirping when I disengage the A/C) and the Harmonic balancer (it doesn't look like it is wobbling very much). Both of those are pretty pricey parts. Related: Anyone know why the Bentley manual wants some kind of special tools to lock the flywheel for N55 manual and automatic transmissions for replacing the harmonic balancer? I have a DCT so I am not even sure if this applicable and the N54 version requires no special tools. It's not like the thing is keyed in either case. Seems to me the only thing it might be preventing is rolling the crank in reverse (I assume reverse is CCW?). TIA for any collective wisdom that can be provided...this is really driving me nuts! Here is a video after replacing the belt, tensioner, both pullies and the P/S Pump. Here is the sound (reduced to a chirp now) after replacing the Tensioner and both pullies, again. I replaced them one at a time and it seemed to reduce the most when replacing the larger idler pulley. Again, this was the second time for all. Of note, when I replaced the P/S pump (long story why I replaced that first), it reduced to a chirp as well, then came back to the levels in the first video. When I replaced the belt/tensioner/pullies, it got a little better, then back to first video levels. I fully expect it will be back to the first video levels in a week. Granted, it was a lot colder when I did the initial replacements (in the 30's). Now it is in the 40's and 50's in the AM so that could be "helping". __________________ Best, Andy '12 E82-PS2,Stoptechs,Clubsports+M3 bits,Accusump,Wagner DP+EVO III FMIC,ERCP,BMS Intake,Mason Strut Bar,Wedge Tune Last edited by AndyW; 03-22-2019 at 12:07 AM.. Reason: New info.
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03-21-2019, 06:22 AM	#2
Mybimmer Private 20 Rep 85 Posts Drives: F20 118d & E82 135i Join Date: Oct 2015 Location: Emerald VIC, Australia iTrader: (0)	Trying another belt would have been the cheaper and first thing to rule out. You're gonna kick yourself if it's the belt dude.
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03-21-2019, 08:07 AM	#4
tracer bullet Brigadier General 2403 Rep 3,534 Posts Drives: '11 135i , '15 X3 35i Join Date: May 2011 Location: Saint Paul, MN iTrader: (1)	OEM belt? Even if it is, any chance it's not the correct width or something? Wish I had a better idea, really interested in how you solve this. Mine only squeaks for 1/2 - 1 second after startup but I read these threads and wonder what will happen next and if there's a tried & proven solution.
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03-21-2019, 09:24 AM	#5
Gizmo135i Second Lieutenant 116 Rep 264 Posts Drives: 135i n55 Join Date: May 2016 Location: Park Ridge NJ iTrader: (0)	Are you sure it’s the belt? It’s pretty common for the PCV valve to make a noise like that. The way to test it is to remove the oil filler cap while the noise is happening, if it goes away it means there is too much vacuum inside the crankcase which causes air to leak past the front or rear crankshaft seal and make a squealing noise. Another thing that could cause that noise is the oil filter, if you have an aftermarket one installed you might want to change it with an oem filter and bmw oil. Variations in oil pressure could cause vanos timing to be off which could cause the same noise. Also make sure the stem is still installed in the oil filter cap, sometimes it comes out with the filter and people throw it out. Hope that helps! Last edited by Gizmo135i; 03-21-2019 at 09:36 AM..
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03-22-2019, 03:23 AM	#7
HyeWarrior Major 747 Rep 1,119 Posts Drives: 2012 135i DCT Join Date: Aug 2010 Location: San Dimas, CA iTrader: (1)	Lol sub'd I have a very very similar sound and maintenance history. I was convinced it's my alternator too, but I've been lazy to tackle the project. Interested to see if it resolves for you!
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03-22-2019, 08:28 AM	#10
OkieSnuffBox Major 1803 Rep 1,011 Posts Drives: '13 135i Join Date: Jan 2018 Location: OKC, OK iTrader: (0)	I swear I have the same thing at startup, or if the idle dips low, but my Indy guy has assured the tensioner and everything are fine.
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03-22-2019, 11:45 AM	#11
MightyMouseTech Major General 4338 Rep 6,196 Posts Drives: 13 135i 6MT LeMans Blue MSport Join Date: Feb 2013 Location: Ottawa, Canada iTrader: (0)	Best way I know to test if it's the belt is to put a bit of talc (baby powder) on the belt. If there is any oil contamination on the belt, the talc will absorb the oil and provide grip. Usually the noise will go away instantly.
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03-23-2019, 04:26 PM	#12
SoFloE82 Private 6 Rep 43 Posts Drives: 135i Join Date: Sep 2011 Location: SoFlo iTrader: (0)	I had a the same sound which turned out to be a oil filter housing leak. The oil was leaking onto the belts causing a squeak. I know you replaced the belts and the noise remained so I doubt this is the issue but take a look. If you've spent some time under the hood, I'd think you would have caught it by now, but just take a second look at the valve cover. Make sure you dont have a small leak anywhere. I'm at 60K and I've had bother an oil filer housing leak and a valve cover gasket leak already. Good luck!
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03-26-2019, 05:12 PM	#13
chrisw27 Private 7 Rep 71 Posts Drives: E82 135i N55 DCT Join Date: Apr 2015 Location: Sydney, Australia iTrader: (1)	Hi Andy, i am also interested in this, as i have what seems to be the same noise. It happens when the engine is fully up to temp, and even then only after spirited driving. It definitely came on after that bloody OFHG leak. So far i have only cleaned the belt and pulleys, next step is to replace them all. Re the alternator, i believe changing both bearings - front and back - is possible. They are designed to be serviceable, and i have done this on my wife's e46. I have not seen a DIY for an n5x though...i would personally attempt this before paying $$$ for a replacement.
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03-26-2019, 10:38 PM	#16
AndyW Supreme Galactic Commander (one galaxy over...) 667 Rep 1,777 Posts Drives: '08 E93, '12 E82, '13 E93 M3 Join Date: Feb 2012 Location: Washington, USA iTrader: (5)	Found this...https://www.maniacelectricmotors.com...042106052.html __________________ Best, Andy '12 E82-PS2,Stoptechs,Clubsports+M3 bits,Accusump,Wagner DP+EVO III FMIC,ERCP,BMS Intake,Mason Strut Bar,Wedge Tune
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03-26-2019, 10:48 PM	#17
AndyW Supreme Galactic Commander (one galaxy over...) 667 Rep 1,777 Posts Drives: '08 E93, '12 E82, '13 E93 M3 Join Date: Feb 2012 Location: Washington, USA iTrader: (5)	On a related note from looking at several DIYs...you really have to remove the OFHG to remove the Alternator? Kinda ridiculous IMO. __________________ Best, Andy '12 E82-PS2,Stoptechs,Clubsports+M3 bits,Accusump,Wagner DP+EVO III FMIC,ERCP,BMS Intake,Mason Strut Bar,Wedge Tune
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03-27-2019, 11:06 AM	#18
thibb001 Private 12 Rep 55 Posts Drives: 2009 BMW 135i Monaco Blue 6MT Join Date: Jul 2017 Location: Atlanta, GA iTrader: (0)	I would try replacing with OEM belt. I had the same squeak a few weeks ago and it turns out i gota little bit of oil on my belt after changing out my oil filter housing gasket. I couldn't see oil on the belt but as soon as i changed it no squeak.
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03-27-2019, 06:32 PM	#19
dtla1 Colonel 828 Rep 2,232 Posts Drives: 2011 135i, Space Grey Join Date: Apr 2014 Location: Silicon Valley iTrader: (2)	Any other Oil Leaks around the car? Like Rear Main Seal, or the Oil Pan Gasket itself? Your test for releasing the pressure on the PCV by opening the filler would prob make it go away, but a tiny leak somewhere could cause a whistle like this.
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03-27-2019, 08:48 PM	#20
Mybimmer Private 20 Rep 85 Posts Drives: F20 118d & E82 135i Join Date: Oct 2015 Location: Emerald VIC, Australia iTrader: (0)	Also check belt direction. Some have a rotation direction shown by arrows on the belt.
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