ROC OUT

About 7 months ago, I lubricated the rubber around the targa top on my C6 with GM dielectric silicone grease (or whatever is recommended in the owner's manual). Shortly thereafter, I started hearing a humming noise which seems to be coming from the portion of the roof panel near the passenger side sunvisor. The noise starts when I reach speeds of around 65 to 70 mph. and continues unless I slow down below 60 or speed up past 75 mph. I have never had problems with this in the past having owned the car since new in June of 2007.

Any idea what might be causing this noise? Anyone have this same problem. Will take the car in to the dealer if necessary but thought would try the forum first. Note, I assume it is wind noise but it may be a low tone vibration of some sort.

Thanks in advance.

Don

torquetube

If this was three years ago, it would be a near certainty that you were experiencing roof panel delamination. It's possible that you have one of the few cars that didn't get its roof panel replaced, or one of the cars with the unfortunate foam-injection non-fix.

Push up on the panel near where it makes the noise and see if you can get it to pull away at all from the magnesium frame. Also try pulling up from the outside edge. If any gap opens up, your roof is done and you're owed a new one.

Another possibility is that the roof latches are simply misadjusted, and the panel isn't being pulled down tightly enough against the weatherstripping. Does the roof panel appear to be aligned properly with the windscreen?

ROC OUT

Thanks, Torque! Yes, everything seems to be aligned properly.

I will try your recommendations to see what can be found. I will also take the top off and check out the alignment pins.

I have a 5-year extended warranty so replacement, if necessary, should not result in out-of-pocket costs to me.

Don

freeride59

I own a 2008 coupe and have the same problem at 67 mph. My noise sounds like a high frequency farting sound, that is coming from dead center near the rearview mirror. I put some electrical tape where the top meets the seal and it helped a little bit. It sounds like air getting underneath the seal ,and vibrating like a whoopie cushon.
Anyone else have this?

ROC OUT

I would say that your problem and my problem are identical given the descriptions of the noise we are experiencing. Once I have had a chance to try Torque's suggestions, I should know more.

c54u

i speculate that your windshield cowl is loose.....why not try taping it to the windshield and see if the noise is there at the higher speed that you hear the noise.

some noises will originate where you do not expect them to and reflect off other parts in your car.

of course i could be way off base here.

ROC OUT

Thanks for the response. However, I don't think I know what a windshield cowl is? Can you explain?

Boomer111

Outside bottom of front window fits over bottom of glass. It has been the cause of a noise like bee in a coffee can. A recommended fix is to apply a bead of silicon user the cowl to secure it to the glass.

Boomer111

Under the cowl

ROC OUT

Thanks, Boomer, I will check this also.

c54u

yeah, just like boomer111 said....it is the plastic piece at the bottom of the front windshield....you can tape the top of the cowl along the windshield to the windshield temporarily and take your car out to test to see if that stops the noise....if it does, put some silcone underneath the cowl to secure it to the windshield

Boomer111

What we endure for our Corvettes well being, it could be a DIY TV reality show. So many home remedies.

freeride59

Based on recommendations in this thread I examined the plastic cowl at the base of the windshield. Sure enough half of the clips were not connected and the cowl was hanging in the breeze. I looks like someone removed the cowl to change a widshield and never installed it properly. I just need to do a highspeed bonzia run to test out the repair.

Thanks for the advice, you guys are awesome!!

AirBusPilot

I actually had to use some clear silicone to "glue" it down on the passenger side. I wasn't really loose, but there was a small gap. That fixed it.

Danko

So, like me, you notice noise coming from the passenger side...... A month ago, I got up over 140 a couple times and REALLY heard some noise, but it was not the car. I am guessing you are married. You are, aren't you?

the law

My 09 coupe was making a noise that I thought was coming from roof on passengers side by sun visor. Dealer replaced the cowl and no more noise, check to see if cowl sets tight to windshield.

LTR

The humming noise was from the cowl at the bottom of the windshield. I used a silicone adhesive and ran a bead all the way across just under the top lip of the cowling. Quiet as ever now. My roof popping was eliminated by cleaning/greasing the seal, tightening the fasteners and adjusting the rear latch assembly. I had to heat up and bend my rear latch hook so it would clamp down tightly.