Possible Solution to problem whistling noise.
I purchased a 2008 Altima 2.5 S, and when the window is down, there is the same annoying whistling sound that you discribe. I get this noise between 40 and 60 mph. I did a little "detective" work and I discovered that if I covered the side view mirror with a towel, I did not hear the noise. I examined the mirror and saw that on the botton portion of the mirror, there is a seam. I purchased for a few dollars a clear silicone adhesive sealer, put down a narrow bead in the seam, and 99% of the whistling noise is gone. I felt this was a better solution than going to the dealer, who would either not do anything, or do the same thing I did, or worse, replace the side view mirror. That could open a whole other can of worms. If you take your time, the silicone seal will not be visable...and it worked for me. Hope this helps.
Last edited by Lscarlt; 05-12-2008 at 05:07 AM.