Whining sound?? Any idea what this is?

StudioWizard · Post by **StudioWizard** » Sat Jan 27, 2024 6:47 am

Hey all

My car has an intermittent whining sound coming from the engine area. I've taken it to my mechanic a couple of times and he's actually not sure what is causing it for sure. He says it might be the alternator bearings or some other part going bad in the unit, or it could be a belt, or....???

It typically happens when the engine is cold and typically goes away after driving it for about 10-15 minutes, but then sometimes it comes back even after driving for an hour... hence, intermittent. And frustrating!

Anyway, here's a link to a very short video to see if anyone has heard this sound and knows what it is.

https://youtube.com/shorts/r9gAzb6z5ok?feature=share

Much appreciated!!

Trav · Post by **Trav** » Sat Jan 27, 2024 10:47 am

When you say you have taken it to your mechanic, have you actually paid him to diagnose it or just stood asking advice? He isnt going to tell you the answer. But it does sound like a small bearing.

Stevepj · Post by **Stevepj** » Sat Jan 27, 2024 12:48 pm

Search for noisy oil filter or oil filter noise on here, that might be your problem. When were the oil and filter last changed?

j3nks79 · Post by **j3nks79** » Sat Jan 27, 2024 12:55 pm

Take the belt off and run it.
If the noise goes then it’s either the tensioners rollers or alternator. Quite simple to diagnose.
If it’s not that the a crushed in oil filter can also make a whistle type sound.

StudioWizard · Post by **StudioWizard** » Sat Jan 27, 2024 4:26 pm

Trav wrote: ↑Sat Jan 27, 2024 10:47 am When you say you have taken it to your mechanic, have you actually paid him to diagnose it or just stood asking advice? He isnt going to tell you the answer. But it does sound like a small bearing.

I've paid him many thousands of dollars already to fix a multitude of things to get this car back into top shape, including rebuilding the tranny, so yeah, he was going to make his money.

StudioWizard · Post by **StudioWizard** » Sat Jan 27, 2024 4:27 pm

Stevepj wrote: ↑Sat Jan 27, 2024 12:48 pm Search for noisy oil filter or oil filter noise on here, that might be your problem. When were the oil and filter last changed?

It was changed in the last couple of months, but it was doing this before the oil change (and after).

StudioWizard · Post by **StudioWizard** » Sat Jan 27, 2024 4:30 pm

j3nks79 wrote: ↑Sat Jan 27, 2024 12:55 pm Take the belt off and run it.
If the noise goes then it’s either the tensioners rollers or alternator. Quite simple to diagnose.
If it’s not that the a crushed in oil filter can also make a whistle type sound.

He suggested changing the alternator out as the first step, but said he felt it was a waste of money at this point. His view that as long as the car runs fine, leave it. My view is that I'm not getting any younger and I want to enjoy the car NOW, which doesn't include hearing a whining sound. haha Also, I don't want the alternator to fail on me when I'm going somewhere important... if that's what it is.

Is it pretty easy to remove the belt?

j3nks79 · Post by **j3nks79** » Sat Jan 27, 2024 5:41 pm

StudioWizard wrote: ↑Sat Jan 27, 2024 4:30 pm
j3nks79 wrote: ↑Sat Jan 27, 2024 12:55 pm Take the belt off and run it.
If the noise goes then it’s either the tensioners rollers or alternator. Quite simple to diagnose.
If it’s not that the a crushed in oil filter can also make a whistle type sound.
He suggested changing the alternator out as the first step, but said he felt it was a waste of money at this point. His view that as long as the car runs fine, leave it. My view is that I'm not getting any younger and I want to enjoy the car NOW, which doesn't include hearing a whining sound. haha Also, I don't want the alternator to fail on me when I'm going somewhere important... if that's what it is.

Is it pretty easy to remove the belt?

Yes 5 mins.
You need to find another mechanic. He’s sounds useless

StudioWizard · Post by **StudioWizard** » Sat Jan 27, 2024 7:10 pm

Point well taken.

Thanks!

PDJ · Post by **PDJ** » Sat Jan 27, 2024 9:46 pm

StudioWizard wrote: ↑Sat Jan 27, 2024 6:47 am intermittent whining sound

Is this when your wife is in the car, try driving it without her in the car....

StudioWizard · Post by **StudioWizard** » Sat Jan 27, 2024 10:09 pm

No, that's a louder more constant sound. LOL

StudioWizard · Post by **StudioWizard** » Sun Mar 10, 2024 11:45 pm

So the problem has been found. It IS the alternator. My mechanic replaced the belts (it was time anyway), the water pump (somebody put a crappy plastic in there previously), pulleys and belt tensioner. It wasn't cheap, but I do notice a difference in the engine smoothness.

Replacing the alternator is more expensive than I thought... somewhere around $1000 USD. There are "mobile" mechanics that come to you in a van. Do you guys have that in Europe? I've never tried it here in the US, but the cost is 30% cheaper since they don't have to pay rent.

Any thoughts about that?

tomaszmk · Post by **tomaszmk** » Mon Mar 11, 2024 1:04 pm

My alternator just died - previously had whining sound over 4k rpm.
I think i will go for refurbish job - cost around 130$

I just need to get it off the car, and take it to the workshop.

StudioWizard · Post by **StudioWizard** » Mon Mar 11, 2024 5:52 pm

So, they'll refurbish your alternator? My mechanic says once they die, they're done, but maybe that's what BMW tells him to say. haha

Is yours OEM?

StudioWizard · Post by **StudioWizard** » Mon Mar 11, 2024 5:59 pm

At what point does a failing alternator throw a code? Mine is starting to whine A LOT, but no codes. My mechanic thinks I could let it go until it fails, which could be quite some time (although that whining sucks!!).

And even though it's not showing up as a code yet, is it affecting the performance of the car?

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