I have a BMW sedan 328i xDrive 2014 with about 65k miles on it.

For the last few months I have been noticing a distinct whirring noise when I drive the car at low speeds of around 25-30mph. I cannot hear it at higher speeds probably because the regular engine sound is louder.

It also sometimes jerks at low speeds when I step on the gas though this is not all the time.

I took it to a local place and he first said that the mechanic could not hear it. He said the alternator had problems and changed that.

My problem still occurs. What might be the problem? What should I do? I am reminded that something is not right whenever I it to the point that I feel like I should "rest" my car and use my wife's Highlander instead.

Checked the air intake to make sure air is only coming from where it's supposed to be? No loose connections or rips?

Not a mechanic at all but since X drive could be front differential issues.

Be more specific. Sound is constant or varies with speed? Front, rear? There's lots of rotating mass in play, need to narrow down to engine, trans, shafts wheels, etc.

Is it like this?

Or

I had a Saab 9-3 that sounded like this and it was the windshield gasket.

JSKolache said:

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Be more specific. Sound is constant or varies with speed? Front, rear? There's lots of rotating mass in play, need to narrow down to engine, trans, shafts wheels, etc.

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Sound is clearly heard at low speeds. The pitch goes up as you accelerate and after a point I cannot hear it because it may be too high pitched. If I don't press on the gas or just a little bit, it crawls and is a bit jerky.

Hard to say front or rear, I cannot tell. I will try to see if I will pay more attention today.

tk for tu juan said:

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Is it like this?

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No, it does not sound like this. The sound in the video sounds like a hurricane or a train approaching, the sound on my car seems like something is revolving and making the sound. It's whirring/humming.

tk for tu juan said:

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Or

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It's not this because I hear the problem at LOW speeds, not at higher speeds. So if I am driving at 25mph or below, I can hear the whirring clearly. It seems to increase in pitch if I increase speed from 10 to 25mph.

Choward4 said:

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Not a mechanic at all but since X drive could be front differential issues.

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Let me look that up. Is that an expensive repair?

Is a front differential repair on a BMW expensive?

aTm2004 said:

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Is a front differential repair on a BMW expensive?

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Cute, but I realize "expensive" is subjective. Google says $1277. Not cheap but doesn't break the bank even we go a bit more than that.

Choward4 said:

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Not a mechanic at all but since X drive could be front differential issues.

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You are probably right. I googled a bit and some places say whirring noises is one of the symptoms if a failing differentiator. I will get an appt to get it checked out.

You're right, in the grand scheme of things, $1k isn't that much. But for a car with <70k miles and a brand you know will have future issues with costly repair bills? They'll add up.

This is not my video but this is closest to what I hear.




One poster on the "bimmerpost" forum says he had the same problem and it was an "idler pulley".

I was gonna say maybe a tensioner

I had an idler pulley disintegrate on my 06 M5 at around 85k miles. No warning, luckily I was only doing 35 in the right lane. Buy a mechanics stethoscope and see if you can isolate the noise
https://www.harborfreight.com/mechanics-stethoscope-63691.html

infinity ag said:

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Choward4 said:

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Not a mechanic at all but since X drive could be front differential issues.

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You are probably right. I googled a bit and some places say whirring noises is one of the symptoms if a failing differentiator. I will get an appt to get it checked out.

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A failing what?

Oh a diff. Has the fluid ever been changed?

I have had 2 BMWs and once it gets past warranty, things break down and all are super expensive. I will never buy a BMW again. This is just not me but a bunch of friends who swears they will not get another one. Two BMWs at around 80K started Oil leaks, engine issues, etc.

Has anyone asked OP if it makes the same noise when the car isn't moving and you press the accelerator pedal?

No.

Did anyone suggest removing the belt, then starting the car (for a minute) to see if it still makes the noise?

No.

Has OP visited a BMW enthusiast forum specific to the car... to see if anyone else has experienced an identical set of clues?

No.

There you have it.

Medaggie said:

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I have had 2 BMWs and once it gets past warranty, things break down and all are super expensive. I will never buy a BMW again. This is just not me but a bunch of friends who swears they will not get another one. Two BMWs at around 80K started Oil leaks, engine issues, etc.

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A friend of mine who has had BMWs in the past said the same thing. My car has about 67k miles in 9 years.

JamesPShelley said:

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Has anyone asked OP if it makes the same noise when the car isn't moving and you press the accelerator pedal?

No.

Did anyone suggest removing the belt, then starting the car (for a minute) to see if it still makes the noise?

No.

Has OP visited a BMW enthusiast forum specific to the car... to see if anyone else has experienced an identical set of clues?

No.

There you have it.

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Has anyone asked OP if it makes the same noise when the car isn't moving and you press the accelerator pedal?

Yes, the sound was still there when the car isn't moving.



Did anyone suggest removing the belt, then starting the car (for a minute) to see if it still makes the noise?

Yes. A mechanic did it and the noise was still there. So it was from the engine.




Has OP visited a BMW enthusiast forum specific to the car... to see if anyone else has experienced an identical set of clues?

I went to bimmerfest or some such site, I was not able to find anything. I probably could have posted.

Ok, so the issue is resolved, and yes, it was an expensive fix. I had to give it to the dealer.

Quote:

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REPLACED BOTH ENGINE TIMING CHAIN, OIL PUMP DRIVE CHAIN,

GUIDE ASSEMBLIES AND ALL NEEDED HARDWARE

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Parts, $2000. Labor: $4700.
Total about $6700 and he took some off as a discount but then you add tax to it.

He sent me a video of the part and showed parts that had worn out. He said that the engine could fail in some time and if it did, the engine would have to be junked and that is about 21k basically making the car useless. True or not, I have to go with it.

Glad you got it fixed.

I don't know where you are located, but $6700 is an astronomical amount of money for a N20 timing chain replacement. Especially if it hadn't actually failed yet.

Like 2-3x what it should cost: 8-10 hours labor (@$150/hr) + $1000 parts = $2500 + tax.\

https://bmwinsights.com/bmw-timing-chain-replacement-cost/


The genuine BMW OEM kit is $676.

https://www.bimmerworld.com/Engine/Camshafts/Timing-Chain-Replacement-Kit-N20-RWD.html

What else did they do to the motor? Did they pull it to do the job?

If I were you I would go back through the receipt with the dealer and make them account for the labor hours and exact parts they replaced to get to $6700.

65,000 is a well under the recommended replacement time for this job (80-100k.)

For $6700 they must have torn apart and rebuilt the entire motor - which would make no sense unless the chain had already skipped.

I don't know the value of your time, but you have a valid case to be raising hell. If you bought it new/certified you should contact BMW NA -- because these motors got extended warranties up to 7/70k for the timing chain.

And if their dealer is screwing owners, they might act on your behalf as well.