Faint whistle from e53 3.0

[E53fan16]

Hi guys,

I'm getting a faint whistle on acceleration between 1-2k rpm. In addition, I'm getting codes P0104 and P0107. I had the mechanic check out the issues and he told me it's my CCV . The mechanic said it's not due to an intake leak. The whistle seems to be coming from the bottom of the vehicle opposed to the front engine bay. Also, when I shut down the vehicle I hear a quick sucking noise.

I was on the fence about it being the CCV, because I did the trick of removing the oil cap while in the engine is running and the oil was cap effortless to remove, no suction at all. I'm a bit puzzled.

He told me to order my parts. What are the parts associated with the CCV replacement?