Hi also just joined this thread as just noticed today fume smell in cab and same whoosing noise and thanks to all your threads, popped the bonnet and felt around the pipe carefully and loads of air escaping, mines a 204 2WD done 20K miles, just booked it in under warranty so hopefully the'll replace it with the new modified type but I least I know there is a modified type so I can check.
Same as me, 204 and mine went at 20k too.