Humming / Vibration In Dash Area @ 80 mph
12-16-2012, 11:07 PM
#21
This is exactly the same area the noise I am hearing is coming from. Interesting in that it comes and goes. Didnt notice if when it was worse if the wind blowing and direction had any impact. I am thinking if the wind speed is up, combined with a car going 80 mph in the right direction, might increase the amount of noise I am hearing.
Going to drive the car again this week to work on the highway and see if I get the same noise. If so, its going into GM for a look. If not, and I took it to GM, I am sure I'd get the standard "Dealer can not duplicated condition. No repair required."
Thanks for the ideas as I will check them out.
Going to drive the car again this week to work on the highway and see if I get the same noise. If so, its going into GM for a look. If not, and I took it to GM, I am sure I'd get the standard "Dealer can not duplicated condition. No repair required."
Thanks for the ideas as I will check them out.
12-16-2012, 11:22 PM
#22
Drifting
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Location: O'Fallon Missouri
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George,
99% chance you have a crack in the cowl covering at he bottom of your windshield. Simple GM part and replacement. You cando it yoursel as I did.
Lift the hood and check below your wiper blades. Had a separation of mine. To confirm it I placed some duck tape over the crack at noise was gone.
Changed the cowl out and problem solved. Think the part cost $50 through GM Parts direct online.
99% chance you have a crack in the cowl covering at he bottom of your windshield. Simple GM part and replacement. You cando it yoursel as I did.
Lift the hood and check below your wiper blades. Had a separation of mine. To confirm it I placed some duck tape over the crack at noise was gone.
Changed the cowl out and problem solved. Think the part cost $50 through GM Parts direct online.
12-16-2012, 11:55 PM
#24
Race Director
Vey common problem, buzzing of the windshield cowl.
The cowl doesn't have enough material at the corner of passenger side bend against the glass.
Plus it is a welded two piece and can tear at the seam. Even without the tear it can/will vibrate.
I replaced mine but some will use clear silicon under the cowl attaching to the glass. Can get a little messy just because of the limited contact area available.
At this time I know of no GM design change available.
The cowl doesn't have enough material at the corner of passenger side bend against the glass.
Plus it is a welded two piece and can tear at the seam. Even without the tear it can/will vibrate.
I replaced mine but some will use clear silicon under the cowl attaching to the glass. Can get a little messy just because of the limited contact area available.
At this time I know of no GM design change available.
02-03-2014, 08:04 PM
#27
Racer
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to be honest i am not too thrilled at the prospect of having to tape and glue my high performance sports car together, surely there must be a proper fix? i wouldnt go as far to say a recall but at least GM should recognize the issue and advise dealerships to fix the problem rather than b/s us and say they cant replicate it
03-09-2014, 10:00 AM
#31
Race Director
Always had all five clips too.
If you mess with it while on the car it is easy to tear the weld (between the two different material) and things will be worse regarding the buzzing.
This last time I replaced it myself and added caulk at the 5 clips that attach to the bottom of the glass.
So far so good but my hearing is pretty bad now so who knows for sure. No one else has complained but I am usually alone when driving the vette.
Maybe this is GM thinking.....most of their owners are old farts.
03-12-2014, 02:28 PM
#32
Drifting
two sided tape under the cowl in the offending area solves the problem
If nothing else, silicone bead under it with masking tape over it to hold it down until the caulking dries.
PITA but an easy fix
Yes, GM should fix it. I'm sure they addressed it on the c7
If nothing else, silicone bead under it with masking tape over it to hold it down until the caulking dries.
PITA but an easy fix
Yes, GM should fix it. I'm sure they addressed it on the c7
02-11-2017, 08:15 PM
#33
A Bummer of a Hummer in the C6
Yes... the C6 windshield cowl on the passenger side from the end to almost the middle either has or develops a looseness or a gap in some areas and does not fit or adhere as closely to the windshield as on the driver side. It's a design or material flaw courtesy of designers and manufacturers.
So, gently using the edge of you fingers carefully lift the edge of the rubber on the cowl where it meets the windshield and with a wet paper towel clean any dirt, dust or debris out of the area behind the rubber and on the windshield. You just need to lift the edge ever so slightly as you work your way across from about the middle of the windshield to the passenger corner. Now go back with a dry paper towel to remove any moisture or remaining residue. Go to an auto parts store and buy a small tube (maybe $6-7) of clear silicone sealant and cut the screw on filler tip off at about the 2nd or 3rd notch to create a bead of 1/16 to 1/8 inch (small bead... but not micro bead). Starting at the middle of the windshield if possible, then gently lift the edge of the rubber on the windshield cowl and letting your fingers to lead the way of keeping the gap open, begin to fill the gap behind the rubber (and onto the windshield) with your bead of silicone sealant all the way to the corner. After you gently press or allow the rubber molding to settle or conform back to the windshield you may notice some silicone sealant oozing out above the rubber where it meets the windshield. Gently wipe the majority away with a dry paper towel and clean up the balance of any silicone ooze (on the windshield or on the rubber of the cowl) with a paper towel on which you have placed some standard rubber alcohol. Just keep using the paper towel with the alcohol to keep cleaning up the area by gently wiping ithe silicone residue away.
Let it "set up" for a while or overnight. You can even add a slight weight to the passenger corner of the rubber cowl (a brick) to help it maintain contact and get a good seal.
Good luck!
So, gently using the edge of you fingers carefully lift the edge of the rubber on the cowl where it meets the windshield and with a wet paper towel clean any dirt, dust or debris out of the area behind the rubber and on the windshield. You just need to lift the edge ever so slightly as you work your way across from about the middle of the windshield to the passenger corner. Now go back with a dry paper towel to remove any moisture or remaining residue. Go to an auto parts store and buy a small tube (maybe $6-7) of clear silicone sealant and cut the screw on filler tip off at about the 2nd or 3rd notch to create a bead of 1/16 to 1/8 inch (small bead... but not micro bead). Starting at the middle of the windshield if possible, then gently lift the edge of the rubber on the windshield cowl and letting your fingers to lead the way of keeping the gap open, begin to fill the gap behind the rubber (and onto the windshield) with your bead of silicone sealant all the way to the corner. After you gently press or allow the rubber molding to settle or conform back to the windshield you may notice some silicone sealant oozing out above the rubber where it meets the windshield. Gently wipe the majority away with a dry paper towel and clean up the balance of any silicone ooze (on the windshield or on the rubber of the cowl) with a paper towel on which you have placed some standard rubber alcohol. Just keep using the paper towel with the alcohol to keep cleaning up the area by gently wiping ithe silicone residue away.
Let it "set up" for a while or overnight. You can even add a slight weight to the passenger corner of the rubber cowl (a brick) to help it maintain contact and get a good seal.
Good luck!
Last edited by 2009 ZR1; 02-11-2017 at 08:20 PM. Reason: misspelled words
05-16-2017, 07:22 PM
#34
Heel & Toe
Dash vibration
I have read another post sometime back on this. There is a plastic cover at the bottom of the windshield (outside) that may be vibrating at highway speeds. Try taping it tightly to the windshield and bring it up to highway speed and see if that stops it. Hope this helps. 
