My P85D (P64168) built December 2014 has been making a tea-kettle noise at highway speeds for the past several weeks, but I'm having trouble pinning down exactly where it's coming from. The car was in the Tyson's Corner service center this past week for the LTE upgrade (huge improvement in coverage) and to have this and another noise issue checked out (clicking from the rear seat area that started after the next-gen seats were finally installed). Neither of the noise issues were resolved; there was some kind of unexplained (to me, anyway) snafu requiring that the main battery pack be replaced. You can hear the whistle at about the 10-second mark in this video: Photo by Bob Vawter - Google Photos It's buried in the road noise (and probably the phone's noise-cancellation) so I have to turn up my speakers a bit for it to be audible. I'm wondering if anyone has experienced this before and/or has any ideas on being able to resolve it myself before I try scheduling another service appointment; it's consistent and lough enough to be disruptive. What I know: - It starts above 60mph and gets more intense at higher speeds. - The seals around the panoramic roof look clean and in good shape, but I don't have anything to compare it to. - From the driver's seat, it sounds like it's above and to the right. - From the passenger's seat, it sounds like it's above and to the left. - From the right-rear seat, it only sounds like it's from in front. - The radio is off. - The A/C compressor is turned off. - If I put the hvac into recirculation mode, the sound becomes fainter or diminishes entirely, regardless of fan speed. - When the hvac is in fresh-air mode, manually adjusting the fan speed will affect the intensity of the whistling. - Sometimes opening and closing the panoramic roof will cause the sound to stop or start, but it's been much more consistent in the past week. - It seems to happen more in the mornings and not after the car has baked in the sun at work, which could be a thermal-expansion issue or just the auto-hvac settings. Thank you for any thoughts on the matter.