0Anthony @ LGMotorsports

Alright,

Typically I'm the one that everyone goes to for answers but now I have one for you guys.

Anyone have a dash rattle in their C6Z?

Seems to be speed related more than anything, as well as temp related. Doesn't do it when it's over 70 degrees outside, nor does it do it below 65 mph. Isn't RPM related and it has no noticeable vibrations inside the car. The dash has never been apart short of me changing the shifter and it did it before and after shifter install. Has done it over the past 2 sets of tires.

Almost sounds dead nuts in the center of the dash but short of pulling the entire assembly out of the car I can't find anything loose.

It's a 3LZ car if that makes a difference.

2StrikeHtr

Could it be the rattle I've read about from the o-ring that goes bad in the oil tank ?
It had a TSB issued at some point in the past.

Not sure if that would fit the bill as you're describing with the temps and mph; but, with noises anything's possible !

VetteVinnie

Yes! And I only just recently figured out what was causing it. The cowl under the wiper blades has a rubber strip against the windshield, and on the passenger side it has started to separate. The wind was getting under it and causing it to flutter, making a horrendous buzzing sound. I tested the theory by taking a piece of duct tape and taping it to the windshield, and the sound went away. So I bought a new cowl from the dealership (I think it was around $80-90) and installed it over this last weekend. Problem solved!

May not be your problem, but it's something to look for.

0Anthony @ LGMotorsports

That would explain why it does it vs speed for sure. Wonder why it only does it when it gets colder out though.......

I'll grab some tape and seal it off on the drive home and see if I can make it go away.

NOSZ06

Adam_W

AWESOME !

I've had the same buzzing sound from the dash at high speed, and I read some threads saying it could be this vs. that, etc.

But this is the first thread where I read the "duct tape test" and that's what I did not: no tape, buzz is there. With tape, Buzz is gone!

Thank you!

QUESTION:

How do I find the part number or official name of the "Cowl" for my 2008 Z06?

How does one install it? If I'm not very technical or handy, should I just as the dealer service department to install it?

Bluewasp

I had a dash rattle dead center of the dash as you describe. It would appear randomly with no influence from vehicle speed or engine rpm. It drove me crazy

I took it to the dealer and their corvette tech was able to determine the sound was coming from the plastic tubes that connect the dry sump canister to the intake. I believe they are vent lines. The tubes were vibrating against the door for the air con filter housing.

He used a few wire ties to hold them in place and the problem never returned.

I can post pictures of the lines if necessary. Just let me know.

Good luck

Dirty Howie

Anthony

You already know this ....... sounds travel through our cars and can be coming from unthought of places.

My rattle that I swore was in the dash turned out to be the 3 piece air dam. One of the side pieces would vibrate against the center piece as they were worn and the connector loose from too much track wear

Thanks again for supporting the 2013 Corvette Challenge


DH

rabrooks

I have the same issue. Its easy to deal with when you know what it is. The cowl under the wiper on my passenger side is loose to the windshield in certain weather conditions. When I drive the car regularly, there is no problem. When the car sits, it vibrates against the windshield and buzzes throughout the cabin. You can tape it down or slip something under it to prevent the contact. Mine was most evident over 60 mph.
Cheers

Les

Shrinkage? I had that happen once in some really cold water and it scared the hell out of me.

Wass

I had the same problem, and it was the cowl under the passenger wiper. If you look closely, you can see where it separates, or lifts from the windshield. Easy to test with duct tape. I sealed it with clear silicon.

VetteVinnie

It was fairly simple to replace. There are caps over the nuts on the wipers that just pop off, then remove the nuts to remove the wiper arms. It takes a torx bit to remove the screws (I forget what size). Then its just a matter of removing the washer nozzles to transfer them to the new cowl.

EDIT: Just remembered, you also need to remove the rubber weather strip and under it are four metal clasps holding the top part to the bottom part. Those four clips need to be removed. I just used a screwdriver. But be careful. I lost one of them somewhere down in the engine compartment. I only have three holding it on now (which seems fine).

Part number is 25778761.

0Anthony @ LGMotorsports

Now I can't get the stupid thing to do it again to test....

blackbeast99

I too had the same problem...windshield cowl. I had to go at least 85-90mph + to hear it (and radio off). Used some sealant to fix it.

Wass

I've read several posts in the past where the high speed (+60 MPH) windshield cowl noise would go away if the A/C recirculate button was on.

WhiteKnight

I just ran into the same problem. Saw this thread, went and checked my cowl and sure enough it was lifting up almost all the way across. I tried silicon and I couldn't make it lay down enough to hold. Then I tried 3M weatherstrip adhesive and that didn't work either. Bought a new cowl and installed it - problem solved. I love this forum.

Adam_W

WhiteKnight - can please share with me the part number for the Cowl, and where you ordered it from?

Thanks!

WhiteKnight

From Evil427 above: Part number is 25778761.

One of my local chevy dealers had it in stock. There are two parts but you should only need 25778761; this part spans the windshield and passenger side. Another part covers the driver side edge of the windshield adjacent to the fender; you should be able to reuse that piece.

Adam_W

Thank you WhiteKnight and Evil427 (sorry I didn't see your response above earlier) !

This forum is awesome for support on so many issues that come up with our cars.

One problem down, ten to go

0Anthony @ LGMotorsports

Mine was up slightly at the middle of the windshield.....replaced it with a new one and it looks to do the exact same thing as far as fitment goes.

However it's a rare December in Dallas today and it's going to be almost 80 the next two days so I don't think I'll get a chance to check the rattle until later this week when it cools off later in the week to see if it rattles then.