Ok i've been scratching my head over this for weeks now i have developed a new noise from my 2004 320cd having previously being panic stricken since finding out about swirl flap faliure when i heard this whooshing noise i was convinced it was linked to this, so i have removed the flaps and replaced with pmw machined blanks,changed the breather,and cleaned the egr but i still have this strange whooshing noise its almost like a dump valve sound, once the turbo spools up above say 2000rpm there is a release of pressure/whoosh noise upon lifting off the gas and changing up gear the car otherwise seems fine doesn't smoke, not using oil,idles well,pulls strong plenty of boost just this noise i found a post by MikeM from oct 2008 with the same problem and i have pm'd this guy just wondered if anyone has any ideas really bugging me now:frown