This doesn't seem to qualify as an appearance or performance mod, so I hope this is the right place to post for help. My 08 CTS has an aftermarket moonroof that the prior owner had installed. It's a nice feature and all, but the wind noise at 45+mph is just not acceptable. It sounds like having a window that is slightly-open ('cracked') all the time. The roof has no leaks, and the seal seems to be in great condition. The glass seems thick enough, but I'm no expert in that regard. I've dealt with it until now, but I'm looking to finally fix the only thing that bothers me about my great car. Any ideas on how to quiet this noise down? Thanks!
Moonroof wind noise
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Since this is an aftermarket moonroof, It may be very difficult to troubleshoot it here because it did not come with your car. While I have a Pano-moonroof, it is stock... It could be a issue with the way the aftermarket moonroof was installed. I would imagine it involves cutting a large portion of the roof and praying all the measurements are correct. I would try to ask a place that installs aftermarket moonroofs if they can trouble shoot it. This is kind of like getting an aftermarket heated steering wheel in your car and then asking CTS owners why it is not working.
Good luck!
Good luck!
Yes, I suppose the question is for a matter that is much more general than the specific aims of the forum. Calling an installer is a great idea. After searching around, I'm also considering trying out a deflector visor. Thank you for your reply, and I will do my best to discover a solution 
'14 CTS-V LongRoof; Audi RS6 Avant; '16 ATS-V Sedan gone; '10 CTS LongRoof gone
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I agree with your last post...looking for some type of lexan deflector to mount in front.
Have you determined where the noise is specifically coming from, i.e., the front of the sunroof or the rear or sides? If not from the front, then the value of the deflector may be diminished.
Have you determined where the noise is specifically coming from, i.e., the front of the sunroof or the rear or sides? If not from the front, then the value of the deflector may be diminished.
As tinman mentioned, a deflector may help. I have a feeling you may just need a better seal in between the glass and the roof. Just out of curiosity, could you post pics? I have never seen an aftermarket sunroof and it would be interesting to see how they adapted one to the CTS (controls etc) and what size they went for.
The noise kinda seems to be coming from the center of the roof, but it's kinda hard to tell. I have never had any leaking problems during rain or washing, but I suppose it could still be some kind of seal problem.
I'm not sure if this is the correct way to troubleshoot the problem but it's a thought. Have one person go around the outside seal with compressed air set at a relatively low PSI and another person inside feeling for a leak.
When you say sounds like a window slightly 'cracked' open, are you talking like an inch or two, or ex: 1/10 inch. I'd think a seal issue would be like the latter and sound like a 'hiss' or 'whistle'. If it's more a low-frequency 'buffeting' sound could be aero. maybe the factory does a better job acoustically isolating the glass. Kind of a goofy idea, but maybe you could fabricate a test deflector (strip of thick cardboard with folded legs/supports at each end, tape) just to see if it makes any noticeable difference.
'14 CTS-V LongRoof; Audi RS6 Avant; '16 ATS-V Sedan gone; '10 CTS LongRoof gone
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I appreciate your line of thought, but how will this pass any speed while driving (being cardboard)? The noise doesn't appear until 45 mph is reached. Good thought, I just don't think it will hold up at speed. Or maybe this, a thought that just came to while while typing. Use that same piece of cardboard and tape it over the front of the sunroof glass to see if a deflector would work. Or instead of that, just try some duct tape over various parts of the glass (just the front, just one side then the other, just the back...) to see if the leakage is taken car of. Just do parts of the glass to eliminate parts of the noise...keep thinking.
I'm 99% sure it is an aerodynamic problem. There is no hissing or whistling, and it is more like having the window open an inch or two. Not quite the same, as it doesn't sound like air is getting in, but a similar wind noise. The curvature of the roof puts the air flow pretty much blasting straight into the sunroof glass, which is probably what I'm hearing. [btw the seals are in fine condition, and not old/dry like they look in the picture -- that white stuff is tree pollen from last weekend that I haven't washed out yet] I have a bigger issue to worry about now, but it sounds like I need to eventually talk to a specialty shop about noise dampening via new glass or some kind of lining. I'm just not that keen on the double-sided tape that is required to fit a deflector, as I would always be worried about it flying off -- I know the 3M Extreme would be good to replace whatever crap comes on it, but I'm not sure about even the best tape holding up to that much consistent pressure. Plus, the deflector might not even do any good. I truly thank you all for helping get some ideas out. I'll update if I am able to come up with a solution
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