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

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:

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

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.

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.

Originally Posted by doru

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.)

Originally Posted by edjack

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???)

Originally Posted by Fast Bob

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...

Idler pulley morning squeal = common, I put oil on it to verify, easy to replace

Thanks Blue for the reply.

Originally Posted by ztom

Idler pulley morning squeal = common, I put oil on it to verify, easy to replace

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?

have you used a mechanics' stethoscope to locate the origin of the noise when that happens? It shouldn't be hard to pin point the location. If you find the noise is indeed from the PS pump, try use the ATF from Redline.

Yeah, a stethoscope might help. It helped me locate a bad water pump. Mine didn't screech though, it made a rattling noise.

Would belts or pulleys cause a constant sound? The intermittent is throwing me off.

What happens when you raise the RPM's say to a steady 2500 or so?

Originally Posted by Fast Bob

Take a spray bottle with water in it....spray a little on the idler pulley....if the noise goes away, the pulley is bad

I soaked the idler pulley and then the 6-hills-5-valleys serpentine belt with Wisk. The noise abated but only slightly, and since it's intermittently loud and silent, I couldn't tell a thing from that test.

I can't imagine a stethoscope working safely because of the moving parts (I mean, you can't just put it on a pulley, can you?) But I'm looking online in AutoHauz for the stethoscope as I'm getting the cabin air filters anyway).

Luckily, I need to replace the serpentine belt (it has cracks); but while I'm at it, I'd rather not take it apart twice so may I ask what is the total list of possible components that could cause the intermittent squeal?

- idler pulley bearings (can be repacked with grease, right?)
- alternator bearings
- water pump bearings
- power steering pump bearings
- the 5-ribbed (6 valleys) serpentine belt

In cn90's diagram, I see a few more parts (do you think they have bearings that could cause that noise)?
- idler roller
- two other rollers
- hydraulic tensioner
- ???

I hate to take it apart twice just so it would be good to diagnose before getting all the parts. I will try the suggested 2500 rpm test if I can get a helper so that I can videotape the noise.

Originally Posted by bluebee

FYI the part numbers may be different for the M54 engine (different style of pulley I think). Last time I tried neither BMW nor an OE shop sold the M54 tensioner pulleys separately (they sell tensioner only). I didn't look on the internet. I hope you have better luck. Also some cars omit the idler roller pulley.

Originally Posted by edjack

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.

+1 on the pulley.

Mine is doing that now but only when stopped while in gear.

Call Bill at Bimmerclinic - He might help you out.
Also, check oembimmerparts,com for the parts you need, then shop around.

Originally Posted by scott0357

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.

Originally Posted by Shires

FYI the part numbers may be different for the M54 engine (different style of pulley I think.

It would be nice to find a diagram of the 2002 525 pulley system as I looked and can't tell where the two belts seem to go.

Plus, they lowered the number of ribs from 5 to 4 in cars built after 9/2002 (I have 5 valleys, 6 hills, which I think they call a 5-rib belt) so these pulleys change even within the model year!

Methinks we should get a group collection up so cn90 can buy a newer E39 so his pictures will correspond to all our BMWs!

I found I think a decent picture labeling half the parts, here:
A: Alternator belt tensioner pulley
B: Alternator belt idler pulley
C: Alternator pulley
D: Power steering pump pulley.

Originally Posted by bluebee

It would be nice to find a diagram of the 2002 525 pulley system

I would have thought RealOEM would have had a nice diagram; but I guess we have to piece it together for the 2002 (like cn90 did for the earlier engine version).

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)?

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.

Originally Posted by bluebee

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.

No! You don't put the stethoscope on the spinning pulley, you'll get hurt. Put it on the housing behind or closest non-moving part to the pulley. As you probe around the non-moving parts, the noise gets louder as the stethoscope moves closer to the source of the noise. Assuming the power steering pump pulley or bearing is bad, put the stethoscope on the power steering pump housing (behind the pulley), the noise would be the loudest at that point. As you move the stethoscope away from the PS housing, the noise gets quieter.

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)

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?