Reported on Rennlist..
"FYI - car back from the dealer... apparently there is a technical bulletin on GT4s about a common failure of the oil separator unit (subsequently re-designed / upgraded by Porsche) resulting in a whining loud high pitched engine sound in the cabin at mid/higher revs (4,000 and above in my case).
If you have noise and your oil air separator part # is 9A110704200 or 9A110704201, then it needs upgrading to 9A110704202"
"FYI - car back from the dealer... apparently there is a technical bulletin on GT4s about a common failure of the oil separator unit (subsequently re-designed / upgraded by Porsche) resulting in a whining loud high pitched engine sound in the cabin at mid/higher revs (4,000 and above in my case).
If you have noise and your oil air separator part # is 9A110704200 or 9A110704201, then it needs upgrading to 9A110704202"