Mine starts at around 35 mph. I took the deflector off (leaving the mounting hardware intact) yesterday before leaving for work to see if the wind noise would go away and sure enough, it was gone. So this morning the hardware came off and I will go without for now until I can find one that doesn't make any noise. I kind of like the way my front end looks with out it again...

 

after installing a ford bug deflector, I have a noticeable amount of wind noise.

 

Yep, thats why I took it off and it is now sitting in my garage waiting to sell it.

 

My big *** tow mirrors I got with the Max Tow package cause some wind noise. It may even drop MPG's.

 

Had a promble with our ford. Husband found it after taping everythig off. Try putting tape over seam on hood, right above grill, then drive and see if that works.

 

I have the same problem, just picked my truck up yesterday (2010 XTR screw) i also have 3 - 2009's with the same setup and they all have the same whistle from the windshield. i'm looking for a cure as it is slightly annoying. So far everything else is awesome on the truck. huge improvement in refinement over the previous generation.

 

Just a heads up, the Ford F150 bug deflector is what caused the whistle on my truck. Took it off and the whistle went away. But there is something to the factory windshield vs aftermarket. Even though I have been using the exact same part number - they are louder. The installer claims the glass all has to meet the same spec, that the only variable would be the seal - and they have paid particular attention to that on the last 2 installs.

Some research shows that the Platinum has an "acoustic" windshield - a thicker layer of the material inside the windshield. So we brought one of these in. Only problem is it does not have the F150 logo top center - I do like that...instead it has an ugly sensor for the automatic rain sensor system that the Platinum is equipped with. I think I may still try this as my next windshield, and hopefully the rear-view mirror covers over that sensor.

 

Just a suggestion for those of you experiencing wind noise from those ugly bug deflectors. Look into a clear bra. They are a bit more expensive but look a whole lot better and offer even more protection. I had the wind noise issue from a deflector on my previous vehicle and said never again. The other thing that can cause wind noise or whistling are some billet grills. Had this happen also!

 

I just bought a 2010 FX4 and had some wind noise and when I looked at all the doors, 2 out of four needed to be adjusted. When you shut them, does is sound hollow? If so it takes about 2 minutes for them to reset it. I still have some noise around the cabin, but I just crank up the sony!!!!!!!!!

Oh yeah, I bought a bug deflector for my 08 XCLT and it made a HUGFE amount of whistling and wind noise. The dealer proved this because when I went to pick it up he taped it up and no noise.

 

I assume this will work for everyone. its definetely the bug deflector in my case and what i did was take some stick on 3/4" wide x 3/8" deep/thick foam gasket/weather stripping and tuck it up in behind the bug deflector where the gaps are biggest (which is the top corners of the grill where the deflector offsets up) and this seemed to eliminate the "squeel" altogether!
Its a cheap and dirty but still concealed way to do this. Hope this is helpful for everyone.