Weird humming/"mooing" sound from exhaust side of engine? Got a video.

[fs454]

I've noticed this noise on and off since I bought the car a couple months ago, but today I could hear it sitting in traffic so I decided to shoot a video of it today after it seemed to become more noticeable.





It's an odd humming noise that sometimes will cycle on and off every ~8 seconds at idle, other times it's continuous. After about 38 seconds in the video it starts fluctuating. Any ideas? It definitely doesn't sound normal.


Thanks in advance!

[Merq]

Did you ever figure out what was making the noise? My N55 started doing this as of late and it's driving me insane not knowing what's causing it.

[Dackelone]

Might be your wastegate vacum actuator(s) ? The DME adjusts the duty cycle at these actuators to control boost and spool up response.

I would go consult with your dealer, since you have this video to show them.

[fs454]

Dropped the car off yesterday, my SA saw the video and thought it was probably a belt tensioner issue, but they'll let me know tomorrow when they actually diagnose it.

[Dmacc]

That noise is coming from your boost solenoids. I had the same thing happen to me, but the noise went away before I could replace them, if it persists, and you happen to throw a 30FF under boost code, i would replace your boost solenoids.

They're about $100 each

[christopherkriens]

Same issue here. http://www.1addicts.com/forums/showthread.php?t=717218

[Dmacc]

Originally Posted by christopherkriens

Same issue here. http://www.1addicts.com/forums/showthread.php?t=717218

The video is set to private

[135IS]

that is one annoying sound

[christopherkriens]

The video is set to private

Fixed

[fs454]

Of course, I get the car back and they "could not reproduce the issue" so nothing was done. I'm now driving cross country from Massachusetts to California with this issue. They claimed that there was nothing stored in the DME either.

Does this always mean that I'm not holding full boost? Or do the symptoms vary?

[christopherkriens]

Did you ever get this fixed?

I did try to crack the oil cap open a little like you suggested, but it didn't have any effect. I got the same response when I mentioned it at the dealer- they couldn't reproduce the issue.

Other than the sound, I haven't noticed any other affects..

[graves4r6]

I got the same noise on my F10 535i. Dealer could not find the problem and It's bothering me. Did you get it fixed? Please let me know. Thanks...

[graves4r6]

To OP,

Did you get it fixed?

Thanks,

N

[fs454]

Hey guys, haven't gotten it fixed yet. When I brought it in pre-crosscountry trip, they claimed they couldn't replicate the issue of course, so I had to embark on my 3400-mile trip worrying about it the whole time.

I've started shooting a video at least once a week on my phone documenting how often I hear it, so maybe that will help me get it fixed next time. I'll keep this thread updated.

[graves4r6]

OK...after going to two different dealerships finally the third one found the problem . They said the noise came from the pressure converter (Boost Solenoid). They replaced it and the annyoing noise is gone!

[Dmacc]

Originally Posted by Dmacc

That noise is coming from your boost solenoids. I had the same thing happen to me, but the noise went away before I could replace them, if it persists, and you happen to throw a 30FF under boost code, i would replace your boost solenoids.

They're about $100 each

I win glad you got it fixed OP!

[fs454]

Originally Posted by Dmacc

I win glad you got it fixed OP!

Not fixed! Haven't gotten a positive response from the dealer regarding it. My fuel pump violently died yesterday morning so I had it towed to Century West BMW here in Los Angeles. Figured I'd try again on this issue while I was in a new dealership, showed the video on my phone and still am not sure if they dealt with it or not.

I'm due to get the car back today, but it seemed as though he was thinking I'm trying to explain wastegate rattle. I brought up my tribulations with my last dealer visit back in MA and said I had turned to the internet for answers and came up with boost solenoids as the potential cause. We'll see later if they took care of it or not.

[IancoleTX]

If the noise goes away when you engage throttle above 0% then I also have this

[fs454]

Originally Posted by IancoleTX

If the noise goes away when you engage throttle above 0% then I also have this

Yeah this is exactly it, that's how I described it to them yesterday, got the car back and again they "could not replicate issue".

Ugh.