Whistle noise from engine

[zimster28]

I have the annoying whistling noise coming from my engine. Regardless of being in Park or Drive, when I step on the accelerator the whistle is there. As soon as my foot is off it stops. I called my dealer and he said it could be the vent valve at the back of the engine. Only a $650.00 part to replace, however he said it should be covered under CPO. I know others have mentioned a tear in the intake tube. I checked and did not see anything. Anyone else have any experience on this subject? Dealer did niot seem certain that it was covered, but I set an appointment to have it checked out. My car is MY 2002 X5 3.0i.