C6 Coupe roof panel noise primer - Long post
 

If you are just looking for a fix to a noise problem skip to post #2.

If you are a 2009 owner with a roof panel noise problem, the information to contact the Assembly Plant can be found in post #3.

There has been a fair amount information posted as well as a fair amount of mis-information posted regarding the roof panel noises that may present on the removable roof panel of the coupe. I wanted to take a few minutes and try to corral the facts in to an easy to use post for people to reference. I will be citing the work of others as well as what I've learned along the way. If I reference a post or thread of yours and you would like it removed please just let me know.

First a little background:

The Corvette coupe has a removable roof panel. The panel is comprised of either a opaque painted SMC panel or a molded transparent polycarbonate panel. The panel is bonded to a magnesium frame. The panel assembly is attached to the car using basically four pins to locate it, two sliding fit clamps and a third latch style clamp as a safety retainer. The perimeter of the frame is mated with a rubber weather seal gasket to prevent wind and moisture from entering the drivers compartment. Half of the gasket seal is on the car at the windshield top frame and b pillar halo and half of the gasket is on each side of the roof panel. These four parts come together to form the complete weather seal.

The Corvette coupe panel is a fairly complex exercise in engineering. It must fit loosely enough such that it can be installed and removed with ease. It must fit tightly enough such that wind noise, moisture and the elements are not permitted to enter the cockpit. The complexity of the design continues when you consider the fact that the side gaskets of the roof panel become the upper window frame that would normally be occupied by a surrounding steel frame that encases the window on most every other car today.

The Corvette roof panel latch handle has undergone some changes during its life. From it’s introduction in 2004 until April of 2007 the latch remained unchanged from the factory and it was a nylon roller that was free to roll and move within the handle. It looks like this:

http://img.photobucket.com/albums/v6...l/100_2681.jpg

In April of 2008 during the 2008 model year complaints of roof panel latch rattle noises were being received and a temporary fix was introduced at the assembly plant to help cure the customer complaints. It was found that by isolating the roller they could minimize and in most cases eliminate latch noise and a campaign of putting an epoxy on the current design roller while the roller was redesigned. I don’t have a photo of a early 2008 latch but it is basically the roller above with a mass of a whitish epoxy cementing the roller in place.

In June of 2008, still during the 2008 model year the newly redesigned latch handles were made available to the assembly plant and were incorporated on the line on June 10th. The new design latch handle uses a plastic roller and it is immobilized with a wedge shape that interlocks with the handle. The new latch handle looks like this:

Attachment 48178992

A little about “noise.”

Noises in an automobile are generally perceived to denote poor quality or workmanship. One issue that we must keep in mind is that every owner is different. Each has a threshold if you will of what they consider acceptable. The roof panel being removable by definition means that it can move. Movement will contribute to sound as surfaces interact with each other. Most owners have never owned a car with a removable roof panel

Common causes of roof panel noise.

Latch handle rattle.

The latch handle design originally was a metal roller which engages a steel plate. Tolerance can allow the roller to vibrate which can produce a tapping rattle sound. Wear or tolerance in the roller itself can allow the roller to move side to side which can also tap the steel plate.


Thermal expansion.

The roof panel, the frame and the gasket materials all have a different coefficient of thermal expansion. All of these mating parts will heat up and expand at different rates. One by-product of this expansion causes to masses to try to occupy the same space and as such something must give.

Lubrication.

The gasket materials that support the removable roof panel are rubber and are prone to the effects of ozone, particle contaminants and wear. As the gaskets age they will become less compliant and less able to support the roof panel firmly and may contribute to movement and noise.

Fit.

Because the roof panel is a manufactured part it means that some allowable dimensional deviation or tolerance is going to be manufactured in. Most of this tolerance is accounted for in the engineering process but it is possible to have a component fall outside of that expected range. When this happens the parts won’t fit together as well as they were designed to fit together. A second contributor to this is an owner that may purchase an accessory transparent top that didn’t come with the car originally. These parts may not fit together perfectly. This will most commonly appear as a panel that sits too low or too high relative to the windshield frame and gasket. It is possible to realign the latch handle and the latch receiver by a simple adjustment of the torx bolt that holds each of them in place.

The next post in this thread will outline some of the areas that you can turn to in an effort to make your car as noise free as possible.

Paul :cheers:

Common fixes
 

Post #2

Here is a direct post of some of the more common remedies to roof panel noise. Remember, each owner is different and each car is different. As such, not everyone reacts the same way to the sounds presented to them. Not everyone can easily assign a cause to the noise they are hearing. Not every car will have the same issues and as such not every car will respond the same way to the fix that some other car has neither for better or for worse.

Lubrication

In most cases lubrication is going to help any condition that you may hear and it should be your first step towards a fix. Lubrication of the weather seals is noted in the manual and it is considered a periodic maintenance item. The most important places to apply lubrication are the front and rear gaskets, the latch handle “roller”, the latch handle receiver (depression in the steel plate) and each of the pins on the roof panel (two at each front corner facing down and two at each rear corner facing rearward. Here are photos of each place that you should consider lubricating either with a GM Superlube or a Silicone based lubricant like that used for O-rings.

Roller

Attachment 48178993

Plate

Attachment 48178994

Attachment 48178995

Front pins

Attachment 48178996

Rear gasket

Attachment 48178997

Front gasket

Attachment 48178998

Rear pins

Attachment 48178999


Rattles

Forum member mrtoner has provided the owner with an exceptional method of binding the roller on the latch handle by the use of a 5/32” e-clip which can be purchased at Lowe’s. This fix will not work on a 2009 car nor will it work on a late build (April-June 9th of 2008). It is designed to work on the original design roller assembly.

The details of his fix can be found in this thread:

http://forums.corvetteforum.com/show...846&highlight=

A second fix that has proven effective is the addition of a small o-ring to the front pin as viewed in this photo:

Attachment 48179000

The thread can be found here as posted by forum member Modshack.

http://forums.corvetteforum.com/show...4&postcount=41


The last course of action of course for pre 2009 owners is to have the latch handles replaced with the new design handle. These are becomming available through the service parts organization and can be ordered through you dealer. For those still under warranty it should be covered. The handle information is called out in TSB# 08-08-67-013A.

Here is a photo of the new design latch handle.

Attachment 48179001

Here is the text of the TSB and the new design handle part numbers:

Service Information
Document ID: 2182040
--------------------------------------------------------------------------------

#08-08-67-013A: Snap, Pop or Rattle Noise from Lift Off Roof Panel While Driving (Replace Front Lift Off Roof Panel Handles and Lube) - (Aug 25, 2008)

Subject: Snap, Pop or Rattle Noise From Lift Off Roof Panel While Driving (Replace Front Lift Off Roof Panel Handles and Lube)

Models: 2005-2009 Chevrolet Corvette

with Removable Clear Roof Panel (RPO CC3), Removable Sun Roof Panel (RPO CF7) or Dual Removable Roof Panels (RPO C2L)

--------------------------------------------------------------------------------

This bulletin is being revised to update the model year to include 2009. Please discard Corporate Bulletin Number 08-08-67-013 (Section 08 -- Body and Accessories).
--------------------------------------------------------------------------------

Condition
Some customers may comment on a snap, pop or rattle noise coming from the lift off roof panel while driving.

Cause
This condition may be caused by the nylon roller inside the left and/or right front roof panel latching handle becoming loose and causing the roller to move on the pin, creating the noise.

Correction

Replace the left and right front lift off roof panel handles (1) and lube. Refer to Roof Lift Off Panel Front Latch Handle Replacement in SI. The updated handles have a new design ramp insert in place of the nylon roller.

Technicians are to apply GM Super Lube® with PTFE, P/N 12371287 (in Canada, P/N 10953437) to both sides (left and right) at the following areas:

Apply GM Super Lube® around the entire guide pin ball (1) on the roof panel.

Apply GM Super Lube® inside the "pocket" of the stainless steel track (1).
Parts Information
Order the left and right handle for each lift off roof panel.

Part Number
Description

19206591
Handle, Roof Lift Off Panel - Left

19206592
Handle, Roof Lift Off Panel - Right

12371287 (US)

10953437 (Canada)
GM Vehicle Care Super Lube® with PTFE

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation
Description
Labor Time

B9849*
Handle, Lift Off Roof - Front - Both - Replace
0.4 hr

Add
Second Lift Off Roof Panel Handle - Front - Both - Replace
0.3 hr

Add
Apply GM Super Lube®
0.1 hr

*This is a unique labor operation for bulletin use only. It will not be published in the Labor Time Guide.


Fit

As indicated you may find yourself in a position of having to adjust the fit of your roof panel. There are torx screws that hold the latch handle and the latch receiver plate in place on the car. An excellent thread on adjusting the receiver plate can be found here:

http://forums.corvetteforum.com/show....php?t=1489234

Here is a photo of the screw on the latch handle itself. It can be loosened and then retightened while it is in place and this may allow for the latch handle to shift in to a better fit on the plate.

Attachment 48179002

Thermal Expansion

Unfortunately there is very little that you can do about infrequent noises due to thermal expansion. The good news is that in most cases it will cure itself in just a few miles. As the car goes from a cool garage to the hot sunny day or having been parked in the hot sun and then driven away it is bound to make some noise. Once each of the materials comes in to thermal equilibrium the noises should stop.

Let me know if you have any questions.

Paul :cheers:

2009 Owners
 

If you are a Corvette owner with a roof panel noise the assembly plant wants to hear about it but especially if you have a 2008 or a 2009 car with the new design latch handle as pictured above. You can send a note to the assembly plant at the following link:

http://bowlinggreenassemblyplant.com/

Just click on the yellow owner feedback button and provide the information requested.

Great post! No issues with my '08 coupe (built 12/07) but I have not changed out the panel yet. The clear panel is in place while my painted panel awaits several coats of wax. :cheers:

Thanks, Paul.....:thumbs:

Lubrication of the seals has worked for me.

Another post that belongs in the FAQ sticky. Great job Paul!

Great info.

Thanks Dan. We'll take care of you when you do change out that panel if you need it. :yesnod::cheers:

Hi Paul:

Thank you for an incredible illustrated post that is clear, concise and most importantly factual with regard to what are actually the causes of "roof popping and creaking" that some owners have experienced.

I for one have an 08 C6 built in 11/07 that has experienced none of the associated problems that some members have had, but was ready to fix what wasn't broken.

As you know; your illustrated post gave me a much better understanding of the cause of the problem; how to prevent it and the steps Bowling Green engineers took in the interim as well as the ultimate redesign.

I for one have decided to leave well enough alone after consulting with you and am pleased to say that by following the maintaince steps that you outlined above; my 2 roofs have remained noise and problem free.

Thank you again Paul; you;re a true asset to the Corvette owners community.:cheers:

regards - Pete

Off topic Paul; there is one issue that perhaps the Corvette engineers can address and that problem is the following:

1. With the targa top removed and both window either up or down; there is a terrible amount of wind noise that enters the cabin cockpit that sometimes under highway speed is unbearable.

Not being an engineer; I've often wondered if perhaps a "clip on" type of lexan plastic wind deflector that could be attached or clipped onto the top leading edge of the windshield with the targa top removed would help deflect or buffer the oncoming wind over top of the vehicle and prevent it from "down drafting" into the cabin?

What I visualize is some type of lexan polycarbonate wind deflector that would be the width and shape of the windshield; perhaps 2-3" in height that would attach to the leading top edge of the windshied.

Perhaps this is something that could be offered as a Genuine Corvette Accessory; much like the wind deflection screen offered for the C6 convertible.

Tim, Jim and Dan. Thank you. :cheers:

Pete,

Thank you for the comments above. :cheers:

Regarding the deflecter, part of the problem with the C6 (and previous Corvettes) is that the rake of the windshield and the height of the roof panel causes a condition that puts the "B" pillar halo higher than the airflow. I agree with you about the turbulence that is created. The good news is that the C6 is better than any before it but the bad news is that is still exists.

Your idea has merit. So much so that it actually was released for the C4 and the C5. A company made a product for the C5 called the Windjammer. Most of the major catalog houses carry them. Here is the design for the C5 as shown at Mid America:

http://www.mamotorworks.com/corvette?frame=1.80

It seems that the C6 could use one as well but as of yet, no one has released it. Since the windshield and roof interface hasn't changed across the entire C6 model line the target audience would be pretty large. I'll see if I can find the right people to pass that along to.

The only problem that I ever had with them was that when you take it off I was never really sure where I would put it if I was travelling. They appear to be pretty large.

Paul :cheers:

This may help also.

I recently installed a vettebin and partition. With the top stowed in the back, windows down, I’d say the wind noise and turbulence has decreased about 40% due the partition. Before the partition, with the windows down and going 50 mph or greater, the pax seat belt flapped so hard against the seat, I would have thought an AH-1W Super Cobra was overhead. Now, there is not enough wind in the cabin to move the belt up to a speed of, opps, better not say. :D

Great summary... Thank you... :cheers:

This write up should be included in the sales brochure as a disclosure/disclaimer of the product, so that the potential owner is not "surprised" when the noises start to occur...

About quality... Some people claim to not have any noise in their cars, if this is accurate, in other words if some cars make noise and some don't, would you agree that this would be an indicator of poor quality? Perhaps not of the design itself but of the final assembly? A product of high quality should have consistancy (sp) ...

I definitely have the noises in my 2006 and will now try the methods provided here. I have been very hesitant to take this in for warranty service because I know it will have to be dealt with by the body shop who will hold the car all day and try a 5 minute fix that I could just try myself. Thanks for detailing these nicely here. I really will try them out. The noises have been annoying.

Great info! :cheers:

Great question and I do agree with your comment about consistency and I agree with you on quality playing a role in the noises. Knowing what I know about the Corvette assembly process and automotive assembly and supply (I worked several years as an engineer in the automotive supply chain) I don't think that I would attribute statistical distribution and dimensional variation to poor final assembly quality perse. What I fear is that complacency and the supply chain is actually a major contributor.

For my reasons behind that, the real noise issue did not start to become prevalent until the 2008 model year. Pardon the pun but previous model years simply had "noise level" problems meaning nuisance types. These are the problems that I attribute to thermal expansion and lubrication above. I'm afraid that something changed in the supplier's process. That could mean a new tool, periodic maintenance or sharpening of the existing tool or worst case something happened that forced the supply to a backup supplier.

It could also mean that the part went out to bid as part of a required year over year cost avoidance or cost reduction process which is unfortunately all too common in the automotive supply process. Cost of parts manufacturing goes up every year. The automotive buying public are very sensitive to price increases in new car purchases so the manufacturers have to reduce costs just to break even. This allows competition among suppliers based on price.

There is always going to be some variation (no matter how small) in a manufacturing process. It has to be worth it to the supplier to keep that variation as small as possible. Automotive manufacturers seldom are able to provide that incentive. The assembly plant receives parts in lots (batches) and they inspect them based on statistical measures that are designed to identify the least number of parts required for inspection to provide the greatest odds of finding a defect. Sometimes those levels aren't adequate. The suppliers are also required to maintain and submit statistical data from their inspection process for review. If the process capability doesn't match the quantity inspected or the distribution of defects is flat across the tolerance it is almost guaranteed that some defective parts will make it in to the final assembly.

There is very little that the plant can do to "inspect in" a suppliers quality. The nature of this part makes any defect other than a flagrant one to be detected in the process. Flat tire, sure. Bad fuel pump sure. A roller that may be .003" smaller than it should be, a little more difficult. Combine all of that with a JIT supply chain and an assembly line that moves regardless it is a better than average chance that a problem can occur in one of the 2,800 parts that go in to the Corvette.

Sorry to be so long. Just my thoughts on the topic.

Paul :cheers:

Keep us posted about your progress. :yesnod:

Great post Paul. :thumbs:

I replaced the old style roof latches with the new style latches (and lubricated the slide bar) on my 08 glass top several weeks ago. The roof rattle was gone instantly...and 1,500 miles later things are still nice and quite up top. :rofl: :rofl: :rofl:

Gene...:cheers:

Paul

Excellent write-up, and helps explain to the more non-technical people why some things happen.

Sometime, it would be a great pleasure to meet you and talk.

:cheers: