SOLVED!: E53 X5 3.0 sounds like dying banshee on fire when I take my foot of the gas

[IkirisTheX5]

@ahlem: When I go tomorrow to pick up my Harbor Freight stethoscope, what exactly will I be listening for? The car, no matter how long it idles or was driven beforehand, will simply not make the banshee scream at any RPM while stationary. Is there a tell tale sound I could pick up on in the stethoscope to alert me to faulty bearings?

[oldskewel]

Too bad it won't happen when in Park. And that is an important clue. It does point away from anything related to the drive belt, but I'd still consider that.

So I doubt the stethoscope will be useful.

Some tests you can still try:
- remove any of the optional plastic panels in the intake area. You'll be taking them off anyway, and just in case there is some aerodynamic whistling due to those you will rule that out when the problem appears.

- get the problem happening.
-- Go in to manual mode and see if that has any effect, while staying at about the same speed. Changing gears at the same speed will change engine RPM. Any change in the noise would narrow it down. For example, maybe it only happens in 5th gear, which would be a good clue.
-- vary speed and see if it changes, while in the same gear
-- shift into Neutral and see if it changes
-- gradual left turn vs. gradual right turn, while maintaining speed (will of course need to find road to cooperate)
-- accelerating vs. coasting vs. light braking

On the drive belt bearings ...
Figuring you'll be putting stuff off and on, you should set as much stuff aside as you can until the problem is solved. E.g., the fan shroud, but make sure any loose wires cannot contact the fan.
You can take the AC belt off and leave it off, just in case the problem is in the AC or the AC tensioner pulley. Test like that.
Similarly, can try with the engine fan removed.

Once you get to the pulleys, with the drive belt off, you can feel them for smoothness and wobble, while they are still installed. Ideally, you will find one of them that feels really loose and maybe even rattling. If not, it is a tough call on whether to just replace everything. Different people have different philosophies about when to bring out the parts cannon.

[bcredliner]

First, independent has said what they think isn't the problem, have they done any troubleshooting or said what the problem might be?

If there has been a check for trouble codes that is the first thing I would do. If it is the transmission related there should be trouble codes. There should be an error code for a vacuum leak and engine wouldn't run as it should.

Sometimes the circumstances associated with a problem are misleading and should be set aside, although, the sound usually helps. I agree that it sounds like a bad bearing or the clutch fan but that is a guess. When troubleshooting I don't remove anything unless it is absolutely necessary. I have damaged a perfectly good part, damaged something else in the process, broken a bolt off, made a mistake in reassembly and had to take it apart again etc. After checking for codes, I would start troubleshooting with stethoscope on the intake and then trace the sound to where it is the loudest. I don't think the engine will need to be hot or the sound present. If there is a problem with a bearing you should hear kind of a grinding noise rather than a constant hum. If you don't hear it cold try when engine is at operating temp. If you loosen a tensioner you should be able to tell if bearing is wobbling or bad without completely removing the belt. Check to see if one of the brackets are loose or broken at the same time. I never run the engine without all belts in place. It's too easy to overheat the engine and the block being aluminum that's high risk. Im addition BMW electronics are very sensitive to low voltage.

Secondary air pump comes on with a cold start to warm up cats. Usually turns off around a minute. It's unlikely it comes on after 30 minutes or stops making noise per your circumstances.

If you have always had the AC on when the noise starts turn if off when it happens so the clutch disengages.

I agree it could be the clutch fan since the level of engagement depends on the amount of heat reaching it. It should spin easily when engine is cold and be running consistent with RPMs when engine is at operation temperature.

There are other potential causes. Troubleshoot, troubleshoot, troubleshoot. It's not yet time to buy any parts.

[IkirisTheX5]

Thanks so much for your advise guys! I had a bit of a breakthrough last night after I ran the X5 for five hours straight mostly in traffic on a 101 degree Texas day…. The noise by that point was as bad as I’ve heard it, so empowered by my $4.99 Harbor Freight stethoscope I was finally able to recreate the sound while stationary by weighing down the gas pedal with the tire jack at around 2,000 rpm [link to video at bottom]. The only problem was I’ve never heard what a good vs bad bearing sounds like through a stethoscope. So for the components I could actually get to with the wand pretty much everything sounded like cacophonous ruckus. With the stethoscope off the screeching is so overwhelming (as you can hear in the video) that it sounds like it could be emanating from any part of engine (but almost definitely not the tranny).

I will say that although I was convinced the sound was coming from the intake system somewhere, by either power of your guys’ suggestion or actual observation, I am now almost convinced it’s a bearing as well. You can hear in the video during the parts where I rev the rpms or remove the jack from the gas pedal how the screeching winds up or down in a “circular” motion like it must be coming from something spinning rather than air being sucked in or through a small space (eg. intake or vacuum related problem).

Yesterday I also took your guys’ suggestions regarding turning the a/c off, putting it in neutral, shifting gears manually, seeing if the sound changes when I turn, but it all came back inconclusive… the only sure things are that it happens when the car is good and warmed up (30 mins+),and is triggered only by releasing your foot off the gas above 2000 rpms and will continue until you either come to a complete stop or accelerate again. Shifting, turning, a/c don’t effect it at all. I have noticed that when I’m idling uphill the noise is slower to go away once I come to a stop.

Anyhow, next step? Would you all agree I need to remove the fan and belt and manually inspect all the bearings along the belt route?



EDIT: I failed to mention last time that at the end of the video I included the results from the OBD scan performed right after I recorded the screeching. There’s like 12 faults and I’m sure most of them have been there since before the noise (I should probably look into a few of those). If you guys notice anything you’ve dealt with before in the codes, advice on that is greatly appreciated also.

*** the EGR or secondary air pump or something was deleted from this car ages ago, before my time if that makes a difference.

VIDEO LINK:

https://youtu.be/qcqBsDuyIEo

[Fifty150hs]

Originally Posted by IkirisTheX5

Thanks so much for your advise guys! I had a bit of a breakthrough last night after I ran the X5 for five hours straight mostly in traffic on a 101 degree Texas day…. The noise by that point was as bad as I’ve heard it, so empowered by my $4.99 Harbor Freight stethoscope I was finally able to recreate the sound while stationary by weighing down the gas pedal with the tire jack at around 2,000 rpm [link to video at bottom]. The only problem was I’ve never heard what a good vs bad bearing sounds like through a stethoscope. So for the components I could actually get to with the wand pretty much everything sounded like cacophonous ruckus. With the stethoscope off the screeching is so overwhelming (as you can hear in the video) that it sounds like it could be emanating from any part of engine (but almost definitely not the tranny).

I will say that although I was convinced the sound was coming from the intake system somewhere, by either power of your guys’ suggestion or actual observation, I am now almost convinced it’s a bearing as well. You can hear in the video during the parts where I rev the rpms or remove the jack from the gas pedal how the screeching winds up or down in a “circular” motion like it must be coming from something spinning rather than air being sucked in or through a small space (eg. intake or vacuum related problem).

Yesterday I also took your guys’ suggestions regarding turning the a/c off, putting it in neutral, shifting gears manually, seeing if the sound changes when I turn, but it all came back inconclusive… the only sure things are that it happens when the car is good and warmed up (30 mins+),and is triggered only by releasing your foot off the gas above 2000 rpms and will continue until you either come to a complete stop or accelerate again. Shifting, turning, a/c don’t effect it at all. I have noticed that when I’m idling uphill the noise is slower to go away once I come to a stop.

Anyhow, next step? Would you all agree I need to remove the fan and belt and manually inspect all the bearings along the belt route?



EDIT: I failed to mention last time that at the end of the video I included the results from the OBD scan performed right after I recorded the screeching. There’s like 12 faults and I’m sure most of them have been there since before the noise (I should probably look into a few of those). If you guys notice anything you’ve dealt with before in the codes, advice on that is greatly appreciated also.

*** the EGR or secondary air pump or something was deleted from this car ages ago, before my time if that makes a difference.

VIDEO LINK:

https://youtu.be/qcqBsDuyIEo

Sounds similar to mine only mine was a little more "musical", but it would not make much if any noise at idle only as the revs came up. But, I could definitely hear noise in the bearings at idle with the stethoscope using the cone end as a "directional microphone". Had to get it pretty close to really pin it down, but once it got close it was very obvious there was a bad bearing there. I think you're dealing with idler/pulley bearings. Could also be the bearings on the tensioner pully. Mine went bad at about 180,000 miles. I don't know the mileage you've got, but based on your sig it sound like a lot. IMHO replacing all the idler and tensioner pullies wouldn't hurt and it's not very expensive. If you are high mileage, they're likely to die soon anyway.

[oldskewel]

LOL nice video

That is a huge, positive change that you can get the sound when in Park. It now rules out problems with the wheels, wheel bearings, diff, AT, CV joints, aerodynamic effects, etc.

You've definitely got some things going on with the codes there, not all (any?) of which could be caused by a bad pulley bearing.

So I'd reset the codes and see what comes back. You may as well work through them, largely independent of the noise. And it could be that you've got a hose that fell off and is causing many things, including the sound.

But now that you know the noise can happen when parked, it brings anything driven by the belt much more into the prime suspect area. Be very careful with the stethoscope and spinning things like the fan - it can be dangerous.

LOL, if all those codes are real (they come back after reset), this might actually be a time when a parts cannon approach has a good chance of fixing something.

But really, I'd start working through them. The sound may be one of the toughest things to track down, and maybe you'll fix the sound as you chase down the codes. Pay attention to when the codes come back. Check often.

[IkirisTheX5]

Originally Posted by oldskewel

LOL nice video

That is a huge, positive change that you can get the sound when in Park. It now rules out problems with the wheels, wheel bearings, diff, AT, CV joints, aerodynamic effects, etc.

You've definitely got some things going on with the codes there, not all (any?) of which could be caused by a bad pulley bearing.

So I'd reset the codes and see what comes back. You may as well work through them, largely independent of the noise. And it could be that you've got a hose that fell off and is causing many things, including the sound.

But now that you know the noise can happen when parked, it brings anything driven by the belt much more into the prime suspect area. Be very careful with the stethoscope and spinning things like the fan - it can be dangerous.

LOL, if all those codes are real (they come back after reset), this might actually be a time when a parts cannon approach has a good chance of fixing something.

But really, I'd start working through them. The sound may be one of the toughest things to track down, and maybe you'll fix the sound as you chase down the codes. Pay attention to when the codes come back. Check often.

——

All good advice. The codes are quite daunting to me. I think I want to start out by changing all the bearing laden components along the accessory drive belt then see what codes I have left and whether that horrible noise goes away. Another person, or maybe even several, have mentioned that at high mileage (mine is approaching 180k and I drive it pretty hard) that it’s a good idea to change all those parts out anyways because if they haven’t gone yet, they will soon.

My only issue now is choosing the right overhaul kit. I’m probably just going to purchase whichever seems most comprehensive and turn it over to my Indy mechanic. I just can’t picture me not losing my mind changing out something like 7 or 8 components and two belts in my driveway in the middle of the Texas summer and without a lift… that’s just not going to end well.

There’s so many iterations of kits out there. If anyone has any recommendations, much appreciated. Leaning towards this one at the moment:

https://m.eeuroparts.com/Parts/47270...yABEgLVZvD_BwE

[Crowz]

My sons e46 325i makes a noise very similar to that and on his its a bad power steering pump or a bad alternator bearing. Leaning towards the power steering since it doesnt work. If he ever comes back by sometime I will try to make a vid of his car. He's to lazy to change either but thats whats doing it on his.


Taking the belt off makes the sound go away is how we diagnosed it.


At least you will know for sure if its an accessory by removing the belt. Of course you cant run it long that way since the water pump isnt turning with the belt off.

[Crowz]

One thing thats different on his that I didnt mention was that the sound only happens at idle or slightly above idle. Giving it gas makes it go away.

[andrewwynn]

Definitely sounds like a bad bearing. The fan clutch engages when hot which changes the load on the belt and the dynamic changes a lot when coasting the engine.


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