random buzzing noise possibly coming from engine?

[alpine24v]

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I just bought my 2009 X5 4.8i a few weeks ago to replace my 2008 335i. I noticed last night when we were out to dinner that there was a random buzzing noise coming from the front end of the car at idle that lasted for about 10 seconds. that was the first time I've heard it (I was outside of the car). heard it for the second and third time tonight, both when the passenger side door was open and the car was at idle. the last time it was pretty loud, but still only lasted about 10 seconds or so. a/c was off both times tonight. I haven't noticed the noise from inside the car, so not sure how often it's doing it.

it's completely random it seems, so will be hard to reproduce at the dealer. any ideas on what it could be? I've tried searching to no avail.

thanks for your help!

[WWONG]

Sounds like the fuel pump priming. My 335i did that a lot.

[alpine24v]

Originally Posted by WWONG

Sounds like the fuel pump priming. My 335i did that a lot.

I know that sound. this isn't when I unlock the car before starting it up. it's much much louder and at idle.