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Video of cold idle engine intermittent squeal (how to determine cause)?

78K views 57 replies 17 participants last post by  Flo e60 520d 
#1 · (Edited)
Attached is a video of my cold idle engine intermittent squeal.

Debugging hints to isolate the cause are welcome.

I replaced the power steering reservoir fluid twice with a quart of Dexron VI which seemed to help a little - but it still came back (the power steering fluid container is empty so you see the white bottom; all the ATF sucked out twice filled the S. Pellegrino water bottle).

Caveat: This is my first video upload ever so I may screw it up.



Here is the video:
 

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#2 · (Edited)
Donna, I thought we need Dexron III, and is there a negative effect in using Dexron VI?
I am not sure what actually the difference is between the different Dexron labels: Dexron III vs. Dexron IV vs. Dexron VI. (I didn't see a Dexron V yet, and I purchased Dexron IV for my steering).
Also, from the pic, your ATF seems grey? This should not be normal - it's light pink.

Addendum: In this case (that grey color), I would try to get rid of as much as I can of that grey stuff - it will kill your steering rack (if it didn't already).
Here are some methods - beware though they are from a v8, which is different from ours - but close enough for procedure, including cleaning the reservoir which has a build-in filter.

GL
 
#5 · (Edited)
we need Dexron III ... is there a negative in using Dexron VI?
AFAIK, Dexron III no longer exists. According to what I had read, GM no longer "certifies" compliance with Dexron III; but not to worry. AFAIK, Dexron VI supercedes Dexron III specifications.

from the pic, your ATF seems grey?
There is no ATF in the picture; my ATF is blood red but what you see in the picture is the WHITE bottom plate of the empty power steering fluid reservoir. I had just sucked out all the fluid so that's why you see the white bottom. It's empty in that picture. (Of course, I filled it up before starting the engine; it took about half a quart.)

 

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#3 ·
The squeal sounds like a bearing, possibly an idler wheel, or alt/water pump/PS pump.

Pull fan, remove belts, and examine all the rotating machinery on the front of the engine. Be sure to mark the operating direction of the belts, so you can put them back on correctly.

The idler pulley bearings can be cleaned and repaced, if not worn or scored.
 
#6 · (Edited)
Pull fan, remove belts, and examine all the rotating machinery on the front of the engine.
I'll look for an M54 DIY. Seems to me I need to replace the belts (they have cracks) and identify whatever it is that is making the noise so that I can replace that too.

Unfortunately that means I'll be taking it apart twice! :(

Once to identify the culprit; the other to replace it. It would be nice to be able to identify the sqeaky wheel without having to remove the belts!

Note: I found an E46 DIY and an 330i M54 DIY (is a 330i M54 engine belt configuration the same as a 525i M54 engine belt configuration???)

 

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#4 ·
Take a spray bottle with water in it....spray a little on the idler pulley....if the noise goes away, the pulley is bad....if not, spray some on the belt...if the noise goes away, replace the belt.
 
#7 · (Edited)
Take a spray bottle with water in it....
I'm going to have to replace the belt anyway (it has 85K miles on it and has cracks).

I'm not sure which is the idler pulley so I'll look that up... ok. it seems to be related to the A/C and water pump so maybe a debugging hint is to run the AC to see if the sound changes...

 
#10 · (Edited)
I need a good diagram of which is the idler pulley. I suspect a search for "cn90" and "idler" will get it for me ... gimme a sec ...

Too bad. Cn90 didn't start any threads with idler pulley in them. Lemme search for something else ...

Ok, searching the Internet for cn90 and idler gets me closer (on bimmerboard) ...

Is this the idler pulley? Is the "idler roller" the same as the idler pulley?

 
#18 ·
have you used a mechanics' stethoscope to locate the origin of the noise when that happens?
How does this stethoscope look from Autohauz (since I'm already getting the filters and serpentine belt and maybe the idler pulley)?

The only problem I foresee is that those parts can rip your arm off so I am not sure HOW I'm going to get a stethoscope in there w/o getting coiled up in the belts, rollers, and fan!

PS: I have a friend coming over to help me videotape the noise since I need to rev the engine and film at the same time for that debugging test.

 

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#12 ·
Yeah, a stethoscope might help. It helped me locate a bad water pump. Mine didn't screech though, it made a rattling noise.
 
#21 ·
Maybe this is a better picture (does it include all the rollers & pulleys)?
(What's the difference anyway between roller, pulley, and tensioner anyway?)

A: Alternator belt tensioner pulley
B: Alternator belt idler pulley
C: Alternator pulley
D: Power steering pump pulley.

E = ?
F = ?
G = ?
H = ?
? = (are there others missing in this picture)?

 

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#22 ·
bluebee i'm have the same problem. ps pump loseing fluid once a week. what i had to do was get under the car and take down the engine sheild too see where the fluid was going too.
but my problem is a little different. i hit, well the rabbit wanted to die. but any ways after running over the little turd i started to have problems. most people need to either tighten some hose's or replace them, cn90 cover this in one of his diy's while working on something else, kind of killed two birds with one stone, or diy.
my problem, is when the rabbit went under, the boot that goes over the tierod, tore, and i think he knocked the tierod back some or enough to mess up the seal on the rack. good luck with finding the problem.
 
#24 ·
OK on the stethoscope.

I'm still confused which pulleys, rollers, and tensioners are in the M54 engine!

And I don't know how to tell if I have spring-loaded or hydraulic belt tensioners.

Is this guess correct yet?

A = alternator belt tensioner pulley
B = alternator belt idler pulley
C = idler roller?
D = power steering pump pulley
E = crankshaft pulley (aft)
F = AC compressor pulley
G = crankshaft pulley (fore)
H = AC belt tensioner
I = alternator pulley
Do I have spring-loaded or hydraulic belt tensioners?
(anything missing)

 

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#27 ·
Hello Donna.
BMW stopped using the mechanical belt tensioner, and is using the hydraulic one.
The mechanical one is more sturdy. The hydraulic one is more prone to failure and does not last as long. AFAIK nobody carries the mechanical tensioner anymore.
If you had that one (which I doubt), you will need to change to hydraulic, and you will need a conversion kit for Drive Belt Tensioner and the hydraulic tensioner. Also, the reason I posted that link before, is because for a strange reason, oembimmerparts still had that mechanical tensioner in stock (a few weeks ago, I believe). They were the only ones.

GL
 
#25 ·
I'm still working on creating an identification diagram for the 2002 525i M54 engine!

If I use CN90's 1998 as the example, do I finally have the right names for all the spinning objects yet?

A = water pump pulley
B = water pump to crankshaft roller
C = deflector roller (aka idler roller)
D = power steering pump pulley
E = crankshaft pulley, aft (for 5-ribbed serpentine belt)
F = air conditioning compressor pulley
G = crankshaft pulley, fore (for AC compressor belt)
H = AC roller pulley
I = alternator pulley

QUESTIONS:
1. Are these the right names for the 535i 2002 M54 engine?
2. What's the difference between a roller, a pulley, an idler, & a tensioner?
3. How do we know if we have hydraulic or spring-loaded tensioners?

 

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#30 ·
well i know mine leaks, and when it is low, on cold starts the pump will whine until the car warms up which at the same time fluid level seems to build up and stops unless it's real low.
 
#31 ·
I have a similar noise, 528i 1997, found that it is when the coolant is low, once I top it up it goes away, so I think it has to do with the water pump although the noise seems to come from the right hand side of the engine. I can't work out where I am loosing fluid from I will have to pressure test it.
 
#32 · (Edited)
when the coolant is low, once I top it up it goes away
Interesting. Easy enough to check. Will do.

Also, I flushed the power steering a few times with Dexron VI.
I bought new belts.
I picked up a mechanic's stethoscope.
And, while I was at it, I replaced the worn power steering reservoir cap o ring.

Here are some related references for xref purposes:
- Fixing the always-wet reservoir cap (magnum, others)
- Power Steering noise (bbmw528i, bluebee,maxout2008,
- Power steering leak (nc530i-2003)
- Cloudy power steering fluid (yknotsail)

 
#33 ·
I really couldn't tell much from the stethoscope. It all sounds loud no matter where I poke it.

All in all, unless I'm missing something fundamental, the mechanic's stethoscope is wholly useless for determining where this type of engine squeal comes from.

To whomever it was who suggested it ... have you ever tried it to locate a squeal?

If so, what's the trick ('cuz I'm missing it)?

 

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#36 ·
I really couldn't tell much from the stethoscope. It all sounds loud no matter where I poke it.

To whomever it was who suggested it ... have you ever tried it to locate a squeal?

There was a very loud constant squealing noise from my 2003 530i engine compartment, and I thought the engine was falling apart. Using the stethoscope, I identified that the noise was coming from the bearing of the alternator. After replacing the alternator, car was back to normal. Also just recently, another squealing noise was developed and it was intermittent. Again using the stethoscope, I identified the noise was from the tensioner (next to the water pump). It is true that everywhere sounds loud when listening w/ the stethoscope, but the noise is the loudest near the origin of the noise. You just need to have more practice w/ the stethoscope. You can start probing from the back of the engine bay where the noise is the lowest and slowly move the stethoscope toward the front. You should be able to tell which locations have the loudest noise. With more practice, you can play doctor for your car. :) When you probe the back of the power steering pump and the back of the tensioner or the alternator, the noises are loud but they sound different. Just play around and pay careful attention to different noises.
 
#34 · (Edited)
i worked for GM for quite sometime. we had a TSB (tech service bulletin) relating to belt pilling. pilling is caused from the belt material gathering in the lands and groves of various pulleys. that in turn would cause the belt to raise itself off the pulley and shift just enough to chirp or squeal. we also had to check for mis-aligned pulleys. PS pump was notorious for that. anyway, we had to go over each and every pulley with a wire brush and a pick to scrape all the pilling out. was a pain in the azz. once that was done the belt was replaced.
as for the stethoscope, use the longest screw driver or socket extension you have. wasnt uncommon for me to use my 30'' 3/8 extension or my breaker bar. then put your ear to the handle and listen... its easy once you get the hang of it and know what to listen for.
g/l
 
#35 ·
as for the stethoscope... its easy once you get the hang of it and know what to listen forl
No matter where I put the tip of the mechanics stethoscope, everything sounded hugely loud and tinny, with vibrations and growls and a cacophony of sounds emanating from every which way.

The fact nothing seemed different when the intermittent squealing occurred, indicates, to me, perhaps, it's a component isolated from the engine block.

The biggest problem was that I couldn't put the tip of the stethoscope on the idler pulley or the alternator pulley itself or any moving component.

So, the use of a stethoscope, at least in my hands, is busted.

 

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#38 ·
It looks like you have the right probing technique. Probe on the metal parts, not the pastic parts since metal is a better sound conductor. If you probe the back of the alternator and then the power steering pump, you should be able to tell the difference. Different bearings produce their own unique sound. Pay close attention and listen for 20s at each of these locations. I was a beginner at using the stethoscope and only took me a couple of minutes to be able to tell the difference in sounds from different parts.
The other way to do this is removing the drive belt, and spin the pulleys and tensioners by hand (don't start the car) and listen w/ the stethoscope. You should be able to tell the difference between a really bad bearing and a good one. Sometimes, bad bearings don't produce loud noise unless under tension, i.e. from the drive belt.
From my own experience, the noise does sound like a bad bearing from one of the tensioners. It doesn't sound like a bad power steering pump or alternator.
 
#39 ·
What would you buy ahead of time for a serpentine belt DIY R&R?

It looks like you have the right probing technique... the noise does sound like a bad bearing from one of the tensioners... It doesn't sound like a bad power steering pump or alternator.
Thanks. I will probe again, especially when the engine starts off stone cold and I won't be pre-occupied with taking a representative video.

BTW, I really did probe more than just a few seconds on each part; I was trying to show, in the video, the "technique", and didn't think people would have the patience to sit through a long period of each probe in the video. :)

I'm not at all sure what disassembly I need to replace the belts and test the tensioners ... so I will see if there's a specific thread for that (otherwise I'll hit up cn90's power-steering pump DIY which might be more than I need).

Since we're already half there, I might need to order the parts ahead of time.

May I ask ... in a "typical" serpentine belt replacement and noise-problem such as mine ... what would you typically buy ahead of time?

- main serpentine belt (I bought a new one already)
- a/c belt (I bought a new one already)
- tensioner 1 (???)
- tensioner 2 (???)
- power steering pump (???)
- (what would you buy ahead of time of a belt R&R ???)
 
#40 ·
You don’t need special tools to R&R the AC and drive belts. Just need a socket (15mm?), wrench and an extension bar, which you can use a 1” hollow pipe from any hardware store and slide it onto the handle bar of the wrench. Your car has two mechanical tensioners: One for the AC (H in your diagram) and one for the long drive belt (B in your diagram). See attached image. Remove the AC belt first, then the drive belt. Draw a picture of how the drive belt is positioned before removing it; you’ll need this picture as a reference when installing the belt. Put the socket (15mm?) on the bolt of the tensioner and rotate clockwise to release the tension, slide the belt off. Sometimes, it maybe helpful in removing the clutch fan to free up some work room. For that, you’ll need a special wrench, which you can buy from Ebay at a discount or from bavauto.com. If you see micro cracks on the belts, replace them. The belts are usually good for 60-70k mi.
 

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#41 ·
#43 ·
Cold Start Squeal

I have this same exact squeal on cold start-up on my 2003 525i.....im relieved to a certain extent that I know what the sound is.....however....I think Im going to live with it for a while....... If I get motivated in the Spring I guess I start wih replacing the idler pulley, 2 tensioners and belts....being that my car by Spring will be almost 8 years old with about 50K miles I think Im due for a belt replacement anyway.:dunno:
 
#44 ·
I have this same exact squeal ... Im going to live with it for a while...
My squeal started in about May and the car died in the middle of the road in about August, so, that gave me 4 months to consider it.

My squeal was intermittently loud and soft and only for the first few minutes (getting worse, of course, over time).

To this day, I do not know what the problem was because it was so hard (for me) to diagnose; but bear in mind that it will eventually show itself as a broken part at some point while you're driving.

I might conclude it was the alternator only because when I removed the alternator for testing, all three tests on the removed alternator failed. That tells me it was something there, perhaps bearings which heated up destroying the electronics.

Or, it could have been a slipping belt (in which case the model-year 2002 alternator frying at 90K miles was just coincidence); or it could have been any one of the pulleys or the idler roller (all of which spun dryly after being removed).

The only problem with waiting is that you'll get stuck in the middle of the road, like I was. If you can handle that, waiting will work just fine (it's what I did since I hate to replace stuff that isn't broken yet).
 
#45 ·
Living with it...

is not as easy as I thought....the sound is so annoying now that I know what the problem is and that is fairly easy to repair...I determined this weekend that I definitely have the mechanical tensioners on my vehicle when I was totally expecting the hydraulic type with my build date of 5/03....the two (2) mech. tensioners (im not going to bother to switch), idler/deflection pulley and two (2) belts are going to run me about $155 delivered from AutohausAZ....I think IM going to go for it in the next two (2) weeks.....now I just need the 32MM wrench and holding tool to remove the fan.
 
#46 · (Edited)
I definitely have the mechanical tensioners on my vehicle when I was totally expecting the hydraulic type with my build date of 5/03
Good that you figured out what you have.

As for "predicting" what it will be, the consensus is that there is no way to tell ... not by VIN ... not by year ... not by build date. Some said even calling the stealer won't help. You can have mechanical or hydraulic or both on any E39.

More details in this bestlinks thread:
- How to tell if you have spring drive belt tensioners or hydraulic belt tension (or both)

the two (2) mech. tensioners (im not going to bother to switch)
I agree with you.

It appears that switching from mechanical to hydraulic is somewhat "problematic" because it's not always a 1:1 fit (you'd think it would be ... ). Apparently you have to get a fitment kit (it is said); plus, nobody says either one is better than the other.

More information in this bestlinks thread:
- Changing from Mechanical tensioner to Hydraulic tensioner for your serpentine belt drive

now I just need the 32MM wrench and holding tool to remove the fan.
See this bestlinks thread for details on the tools:
- How to make your own BMW special cooling & belt drive system counterhold tools (1)

For one users' belt-drive system overhaul, see this DIY here:
 
#47 ·
I received my parts from Bavauto and they sent me aftermarket tensioners and idler pulley manufactured by "uroparts"....they were doing a price match to autohausaz which were OE parts by "INA".....who the heck is uroparts?....I think I'm sending these back.....at least the belts were conti!
 
#48 ·
idler pulley manufactured by "uroparts"....
The recommended brands are listed here:
- Recommended parts & brands for a complete drive belt system overhaul (1)

I don't see anyone mention "uroparts" so maybe we should dig a bit further to see if "uroparts" is also recommended or not.

Here's the short list:
- alternator/ps/wp drive belt (CRP-Contitech)
- A/C compressor drive belt (CRP-Contitech)
- idler roller (INA is OEM, can also get SKF)
- A/C belt tensioner (INA is OEM, can also get SKF or Ruville or Lemfoerder)
- alternator/ps/wp belt tensioner (INA is OEM, can also get SKF, Ruville, or Lemfoerder)
- alternator, 120Amp (Bosch and Valeo are OEM; replace yours with the same as you're taking out)
- viscious fan clutch (Behr is OEM, Sachs is recommended brand, MFC is not recommended)
 
#49 · (Edited)
Getting slightly off-topic here...

but here is a few cellphone pics for the record of these "uroparts". They appear to be close matches to the OEM from what I can tell.

Update...I returned these things today..the Customer Service rep. at BAVAUTO had never heard of "INA"....I re-purchased everything from another vendor.
 

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#50 · (Edited)
the Customer Service rep. at BAVAUTO had never heard of "INA"
Wow. That's a shock. Sometimes I wonder about these guys, whether they're lying or just plain ignorant (note, I didn't say styupid because that's a different problem altogether).

Reminds me of the time I brought my BMW to the dealership for violent shudder and they professed to know nothing about it - even though - I found out later - it's a well known and very common problem (under certain circumstances).

You can only conclude they're ignorant or they're lying ... and you really can't tell which from which. Sorry about that.

Now, by saying that, please understand that I AM IGNORANT too ... but I don't work as a Bavauto or BMW parts person so my expectation of knowing a UROparts from a INA is different. For all I know, it could be the same company with different brands (witness Axxis and PBR & Repco & BendixMintex & MetalMasters, etc. for example).

It's a shame if Bavauto doesn't know this. I'll bet Mark at EAC Tuning or one of the OEMBimmerparts guys would know all about it (and give a recommendation around that experience).

NOTE: INA is "clearly" marked on the OEM tensioner!
 
#52 ·
Thanks to Blue I was able to do the Vanos reseal, pulley and bearing on my newly purchased 530i. Once I got the parts I was able to finish the Vanos, pulley and belt replaced in two days. I hope the alternator and the thermostat lasts for another 20-25k miles as my budget is tight right now.
Anyhow, thanks for the excellent DIY!
 
#53 · (Edited)
I was able to do the Vanos reseal, pulley and bearing on my newly purchased 530i.
Good for you.

BTW, I just ran into this nice video of the BMW idler pulley, before and after, showing the noise that is made in the dry idler pulley versus the new replacement part.

http://sport-with-you.ru/view.php?video=acZ96Jr0zC4&feature=youtube_gdata_player&title=BMW+Idler+Pulley+Noise+%3A+Before+%26+After+%2F%2F%2F+330i+%28E46%29

And, here's a video of a BMW mechanical tensioner pulley noise, both before and after.

http://sport-with-you.ru/view.php?v...tle=BMW+Tensioner+Pulley+Noise+///+330i+(E46)
 
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