HELP! 318ti making funny sound on startup

[GoNuts]

Hi all, pretty much a n00b when it comes to what is making what sound on my car.. It is making a sound like a warbling fan.. The sound starts after the engine sounds like a compressor has been started ( which is about 5 seconds after start and when it is idling )
It only does it at the first start of the day

Here is a YouTube link of the sound

http://www.youtube.com/watch?v=ygdoVZpBpeU&sns=em
In the video I brought the revs up to about 1 1/2-2 and it really makes the noise louder

Thanks for watching and reading! Any ideas??
-Elan

P.S the noise goes away after a minute or so o.O

[HotChickenStrips]

That's the A.I.R. pump, the ones used on many BMW's have a tendency of separating at the top, they are held together with rivets but over time they break and fall off.

If you need more info let me know and I'll give you my number so I can text you some more info.

[GoNuts]

Originally Posted by HotChickenStrips

That's the A.I.R. pump, the ones used on many BMW's have a tendency of separating at the top, they are held together with rivets but over time they break and fall off.

If you need more info let me know and I'll give you my number so I can text you some more info.

Thanks man! Pm'd