AC makes whistling noise above 60 mph
#1
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My 2010 997.2 C2S makes an annoying whistling sound when I'm driving the car faster than about 60 mph. The noise is constant and occurs with all of the windows closed (this would seem to eliminate the mirror whistle as the source of the problem (?)). If the AC fan is turned off, the whistle noise stops. It sounds like the whistling sound is coming from the vent on the top of the dash on the passenger side. The car has made this noise since new. It's at the dealer now, but they have not yet been able to identify the source of the whistle.