Hi, I have an E61 530D and when I start it up and let it idle I can hear a noise coming from the right hand side of the engine compartment, that's the right hand side as you face the front of the car, its like air venting at engine speed and after a few minutes it stops. I have had my hand down the side of the engine feeling for air leaks and squeezing pipes but can't find anything. Anybody got any ideas? thanks Paneuro.

 

Been having a good look and found what could be a possible cause of the noise, the electric vacuum control valve? anybody got any thoughts / Paneuro