Interesting start up noise!

[highonthai]

When cold starting the 318i I get this strange nosie from boot that goes to the airbox. And it lasts until it's warmed up. What is in between the throttle body and the air box that would cause this sound?
Any help would be great!

Scott (new 318 guy)

[highonthai]

Ok, did some searching (should of done it first) and found out it is most likely the air pump. Guess I'll take a look at it in the morning.

Scott

[BMWDRIFTER]

it should sound like a quiet hairdryer.

[gsborden]

Sounds like water is getting into the air pump. When my air pump started going out, it made an awful noise.