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

[IkirisTheX5]

Hi fellow X’ers,

Although been reading and learning from Xoutpost the last couple of years since I adopted my beloved rescue 2002 X5 3.0 (that’s taken me from Texas to NYC to LA and back, and spent several nights at the Salton Sea, in Death Valley and the Badlands having never let me down), this my first official rookie post. So apologies for any gaffs, but I need help, serious HELP!

As of about 90 days, every time I drive the X5 for more than 30 mins straight a higher pitch squealing or whistling begins screeching out of the engine bay everytime I simply release my foot of the gas, and gets louder when I apply the breaks - then - like magic the ear-piercing screech instantly disappears when the truck comes to a full stop or I give it a little bit of gas. It’s so loud it literally sends people begging for change at interjections running off in pain, with ears covered.

Myself and two Indy mechanics I trust and respect have given up on her. So far we’ve changed:

- the valve cover
- the 90° rubber intake elbow boot
- the air filter unit including resonator box
- the DISA valve
- the brake booster
- have performed the smoke test on vacuum lines to no avail
- I sprayed a can of carb cleaner in/around all intake components to detect a breech of some sort - nothing

I don’t know what to do next and I can’t imagine the dealer-stealer can’t help anymore than what I’ve done at this point.

PLEASE PLEASE has anyone ever resolved this in their own vehicle or have any idea what I could check or replace next?

Xoxo

[ahlem]

Get a Harbor Freight stethoscope and check everything being driven by a fan belt.
It could be early bearing failure in any one of a number of accessory and idler pulley components. You can also pressurize various vacuum hoses to a couple psi separately and specifically with a regulator and blow gun with tapered rubber nozzles also from Harbor Freight. This is just a bit different than the smoke test but more of a Hiss test. Some internals of various vacuum devices could be failing and you wouldn't see it via a smoke test.

[cn90]

1+,

- My guess is the belt system, probably some dry pulley bearings...

- Search forum for "Partial cooling overhaul" I wrote a few yrs ago...

[IkirisTheX5]

Thanks for the suggestions guys. Maybe I should revisit those components. I sort of brushed off belts and pulleys after both my indy mechanics threw that notion out the window first. I never second guessed them because the causalities that contribute to the squeal don’t seem belt related. For instance what does me letting my foot off the gas have to do with a high pitch squeal/whistle coming from the engine only when it’s hot… My mind has always been on the intake system because what’s the one thing that closes when you no longer accelerate (take your foot off the gas), air and fuel to the engine, right? Besides so much of the intake is plastic it made sense for something to start whistling only once the engine warmed up and expanded something.

I’ll post a video of the sound in just a sec. maybe one of you guys will recognize it, coz I sure haven’t been able to.

[Fifty150hs]

Originally Posted by cn90

1+,

- My guess is the belt system, probably some dry pulley bearings...

- Search forum for "Partial cooling overhaul" I wrote a few yrs ago...

+2

Sounds like bearings for the idler and tensioner pullies. Had a similar issue several years ago. Used a stethoscope to pin it down. Replaced the pullies and no more noise.

[IkirisTheX5]

Originally Posted by Fifty150hs

+2

Sounds like bearings for the idler and tensioner pullies. Had a similar issue several years ago. Used a stethoscope to pin it down. Replaced the pullies and no more noise.

@Fifty150hs: thanks so much for sharing - that's a great start to my hierarchy list of most likely bearing components to fail in the M54.

You think I should go for a full accessory drive belt kit like the one in the link and knock out all potential problem areas along the belt route?

https://www.fcpeuro.com/products/bmw...iABEgKL8vD_BwE

[Fifty150hs]

Originally Posted by IkirisTheX5

@Fifty150hs: thanks so much for sharing - that's a great start to my hierarchy list of most likely bearing components to fail in the M54.

You think I should go for a full accessory drive belt kit like the one in the link and knock out all potential problem areas along the belt route?

https://www.fcpeuro.com/products/bmw...iABEgKL8vD_BwE

What year is your X? That may not be the right tensioners. I have an '06 and it has the "hydraulic" tensioner. That said, if you can't hear those bearings with your stethoscope, putting those parts in will likely cure your problem if those parts have bad bearings. My X didn't really make much noise at idle either, but with the stethoscope, using the little cone ended attachment, I could here a little bit of bearing noise in my pullies. That's why I went ahead an replaced them.

This is the tensioner my X has: https://www.fcpeuro.com/products/bmw...1287838797-1-2

[IkirisTheX5]

Here is a link to the VIDEO of the sound in question. To refresh, only appears after roughly 30 mins of driving in hot conditions and ONLY when I remove my foot of the gas and coast, then louder when I apply the brakes; disappears immediately when either gas is applied or car comes to a complete stop: https://youtube.com/shorts/GouqH96gN4o?feature=share

https://youtube.com/shorts/GouqH96gN4o?feature=share



(Sorry not sure yet how attachments work on this forum)

EDIT: Now with more video !

https://youtu.be/-blBjHFya0A

[andrewwynn]

take your belt off and run the engine after it’s warmed up of course. Definitely sounds like a bearing situation and I have worked on a car where the tensioner wore out and was angled a little bit I was actually able to repair it by cutting a counter angle in the mount.

That’s sad day when it warms up factor hints at a problem with the fan clutch. You can again wait for it to warm up pop off the fan And see if the sound goes away.

[IkirisTheX5]

[QUOTE=andrewwynn;1207344]take your belt off and run the engine after it’s warmed up of course.

That's a pretty ingenious diagnostic hack... I think I would need to be able to drive it at minimum 20 mins even if I take the belt off warm to convince myself the noise is/isn't there. Will an 18 year old X5 run for 20 mins in triple digit Texas summer heat w/ no belt?