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Discussion Starter · #1 ·
Went to the dealer today and discovered some very disheartening information. According to GM's Document ID:2257485 all 2005-2010 corvettes may be affected by this problem. As listed on the document:

Condition/Concern:

Some customers may comment of a creak type noise in the rear of the car. This noise seems to be induced as the body of the vehicle flexes. An example of this would be turning into a parking lot where the entrance has an incline.

Recommendation/Instructions

Note: Prior to performing the procedure below, be certain that the noise is not related to any suspension components or the panel behind the seat. Common areas of noise can be the rear stabilizer links or "oil canning" on the panel behind the seats. Technicians should isolate the rear body panel behind the driver's and or passenfer's seat to determined if the noisse can be reduced. If the noise is corrected the panel is "oil canning" and transmitting the noise. Oil can noise can be reduced by adding a small crease in the metal to reduce panel movment or adding several dimples to add rigidity to the panel. If the noise is not suspension related or the body panel, it may be necessary to continue with this PI.

Remove the fuel tanks and inspect the frame on both the left and right side of the vehicle. If a void is found, it will be necessary to re-weld this area.

Important: When MIG welding, it will be necessary to use all safety precautions since the area of concern is near the fuel tank(s).

Grind this area clean were welding is needed.
MIG weld area utilizing all safety precautions.
After welding is completed, coat area with rust inhibitor to prevent future corrosion.

Re-evaluate vehicle.
Caution: To avoid personal injury when exposed to welding flashes or to galvanized (Zinc Oxide) metal toxic fumes while grinding/cutting on any type of metal or sheet molded compound, you must work in a properly ventilated area, wearing an approved respirator, eye protection , earplugs, welding gloves, and protective clothing. This information was taken from SI Document 824779. Use labor operation S0017 if welding of the frame is required.

I gathered some of this information from this thread:
http://www.z06vette.com/forums/f62/any-safety-issues-w-c6-z-suspension-113874/
I updated the numbers on the document to reflect what GM is showing today. I am in disbelief that this problem exist and yet GM seems to have done nothing to correct it. This updated bulletin just extends the years of affected vehicles up thru 2010.
It is also worth noting that the 2004-2009 XLR and V series are also listed on the document.

Please if anyone else has experienced this problem make it known here.

I am taking my car in on Wednesday to determine if the frame actually needs welding or if it is another issue as described in the document.
 

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I can imagine what could happen to my car if this "fix" was needed.:puke:
Fortunately, the only creaking I hear is my bones getting in and out of it!!:lol:
 

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The only issue I see with the above info is that the Cadillac XLR-V uses the same steel frame as the base Corvette and not the aluminum frame made at the Dana Plant for the Z06. So it would be extremely odd this issue effects aluminim frame Z06s and steel frame XLR-V but not base Corvettes.
 

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Discussion Starter · #5 · (Edited)
Apparently this affects all corvettes base, ZO6, & ZR-1 according to the bulletin. This seemed extremely odd to me being that the frames are made from two different materials. I was hoping someone here with more knowledge of the vehicle could post up explaining how this could be true.

If the dealer says they need to remove the fuel tank for further inspection I plan to take the car somewhere that has a peep hole camera. I would like to verify the problem actually exist before things are taken apart.


The only issue I see with the above info is that the Cadillac XLR-V uses the same steel frame as the base Corvette and not the aluminum frame made at the Dana Plant for the Z06. So it would be extremely odd this issue effects aluminim frame Z06s and steel frame XLR-V but not base Corvettes.
 

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I dunno.... I've had my car for 3 years. Not a peep out of the rear end! I lump this one in the "if it ain't broke don't fix it" category! :mug:
 

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I've had an annoying squeek behind the passenger seat since about the first week I've owned the car. It happens EVERY time I drive the car!! :mad:
 

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Due to the length of the weld and the angle it is at you might not see with that tool if the weld has just begun to crack with tanks in front of it
I saw one on a Z06 that races a lot and weld was more like a rip.

Keep in mind it it could be the metal sheet by hatch floor behind seat is flexing and needs the fix GM states to do.

Apparently this affects all corvettes base, ZO6, & ZR-1 according to the bulletin. This seemed extremely odd to me being that the frames are made from two different materials. I was hoping someone here with more knowledge of the vehicle could post up explaining how this could be true.

If the dealer says they need to remove the fuel tank for further inspection I plan to take the car somewhere that has a peep hole camera. I would like to verify the problem actually exist before things are taken apart.
 

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That's too much work for the tech's around here. If I have the noise I'll do the repairs myself. My car isn't for some service dept. "specialists" to go on a search and finally destroy mission then xxxx up my car. It's bad enough I have to write up a spec for them to change a clutch. Then help them. I'd give it some serious thought before letting a dealership start to take my car apart unless I was 110% sure what the issue was.

Just my opinion. :mug:
 

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Discussion Starter · #10 ·
I got a hold of a fiber scope today. I have decided to put it on the rack of a local specialty shop to see what we can see before taking it to the dealer. I do not have much faith in their capabilities. Seems every time the car has ever bee there it comes back with a new scratch. :(

What really mkes this bad is the fact Chevy knows of the problem, yet seems to not care enough to fix it before releasing subsequent model years.
 

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I would do a little more work before taking it to a dealer. You have the scope, that's good, maybe you will find something. But you need to isolate the sound, get a friend and have them feel the panel behind your seat as you drive up an incline at an angle. Maybe have them get in the trunk and see if they "feel" the sound anywhere. Don't assume you need to weld the car which seems to be the approach you are taking. Be vigilant and check everything back there.

The panel behind the seat is well designed, weld along the top, folded edge at the floor and riveted to the bottom brace and a folded edge at the door opening and riveted again plus adhesive.

I would be darn sure of myself before taking it to a dealer and I would sign my name right next to the odometer reading on the service sheet and ask the service manager to do the same.

You are from KY, any chance you live somewhat close to the Dana plant? I would go on a tour and take photos and see what welds appear to be the issue. I have photos of the frame but I don't have any shots behind the seat panel which is what you really need. The guys at the plant were great and one pointed out every ground point on the C6 frame which I took photos of if anyone needs assistance in that area.
 

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Just so it is clear there is two different issues.

Some noise is due to the metal sheet behind seats of the hatch that has too much flex causing noise and as the TSB for this is to dimple or crease that sheet to make it more rigid.

Maybe to test that as causing noise is to move seats forward put something between seat and that back area and then move seats back to cause pressure against the sheet to prevent it from flexing and then test driving on a road that would cause some flex to suspension ?

The other issue but a serious one is weak weld to frame that under stress cracks and then allow movement.

I'd assume GM for cost saving had XXx frames built as the same batch at the same time so reason problem exists across model years.

I would do a little more work before taking it to a dealer. You have the scope, that's good, maybe you will find something. But you need to isolate the sound, get a friend and have them feel the panel behind your seat as you drive up an incline at an angle. Maybe have them get in the trunk and see if they "feel" the sound anywhere. Don't assume you need to weld the car which seems to be the approach you are taking. Be vigilant and check everything back there.

The panel behind the seat is well designed, weld along the top, folded edge at the floor and riveted to the bottom brace and a folded edge at the door opening and riveted again plus adhesive.

I would be darn sure of myself before taking it to a dealer and I would sign my name right next to the odometer reading on the service sheet and ask the service manager to do the same.

You are from KY, any chance you live somewhat close to the Dana plant? I would go on a tour and take photos and see what welds appear to be the issue. I have photos of the frame but I don't have any shots behind the seat panel which is what you really need. The guys at the plant were great and one pointed out every ground point on the C6 frame which I took photos of if anyone needs assistance in that area.
 

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First understand that Aluminum has definate performance advantages by saving weight but gives up some endurance and reliability due to it being a "softer" and therefore more maleable and possibly weaker metal than steel.
However if engineered correctly, manufactured correctly and combined in the proper alloy it can be a reasonable substitute for steel.

1. The most common failure is the Aluminum A-Arms, especially after an off course shunt or accident. Most common problems are inability to align or a vibration and or uneven or undue tire wear. One should always suspect and check the A-Arms for trueness after a shunt or accident.

2. The Aluminum frame on a C6 Z06 IS suitable for competition but needs additional stiffening.
Note that the factory added additional gussetting to the front and rear frame end pieces when they switched from Steel to Aluminum.
I recommend the following when preparing the Aluminum frame for competition:
A. Complete the shock/A-Arm mount welds.
B. Add additional gussetting in the mid frame sections
C. Use a thicker tunnel plate:
Good = 1/8" Steel (stong but heavy)
Better = 1/4" Aluminum (lightest)
Best = 3/16" Titanium (strongest and equal in weight to Aluminum but expensive).
D. Install additional frame stiffeners:
- at least a BK Auto or Hardbar Harness bar
- SCCA approved 4 point roll bar (better)
- SCCA approved roll cage. (best)

For a dual use car that sees occasional competition I would first do C. & D. appropriate to class rules.
For a National level or Pro competition or a dedicated race car I would consider all of the above (A+B+C+D).
 

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Discussion Starter · #14 ·
Thanks Paul I appreciate your advice.
I probably should have given a little more history but sometimes get lazy when it comes to typing.
I have been chasing this noise for about two weeks before turning to these forums for help. That is when I discovered the older bulletin about the frame and decided to visit the dealer to verify the document.
Previous to the dealer visit I have had the car to a local shop trying to diagnose the problem. The shop owner does a lot of work on suspension and engines for guys in this area that track or autox their cars. He has set up several cars for me for autox and he is also corner balanced this car for me, so I trust his opinion. Both of us felt that the noise was not coming from the panel behind the seat and he felt confident that it was not a suspension component.
I purchased this car with a 1012 miles on the odometer and it was suffering from the delaminating roof problem that has been widley talked about here and other forums. The car now has 5300 miles on the odometer and I wonder if the time spent driving the car with the defective roof panel could have caused additional stress on the frame. The roof panel was fixed at about 1200 miles.
I did not know you could tour the dana plant and this is great information for me, thanks again. I will try and get there late this week or early next armed with my camera and notebook.


I would do a little more work before taking it to a dealer. You have the scope, that's good, maybe you will find something. But you need to isolate the sound, get a friend and have them feel the panel behind your seat as you drive up an incline at an angle. Maybe have them get in the trunk and see if they "feel" the sound anywhere. Don't assume you need to weld the car which seems to be the approach you are taking. Be vigilant and check everything back there.

The panel behind the seat is well designed, weld along the top, folded edge at the floor and riveted to the bottom brace and a folded edge at the door opening and riveted again plus adhesive.

I would be darn sure of myself before taking it to a dealer and I would sign my name right next to the odometer reading on the service sheet and ask the service manager to do the same.

You are from KY, any chance you live somewhat close to the Dana plant? I would go on a tour and take photos and see what welds appear to be the issue. I have photos of the frame but I don't have any shots behind the seat panel which is what you really need. The guys at the plant were great and one pointed out every ground point on the C6 frame which I took photos of if anyone needs assistance in that area.
 

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Thanks Paul I appreciate your advice.
I probably should have given a little more history but sometimes get lazy when it comes to typing.
I have been chasing this noise for about two weeks before turning to these forums for help. That is when I discovered the older bulletin about the frame and decided to visit the dealer to verify the document.
Previous to the dealer visit I have had the car to a local shop trying to diagnose the problem. The shop owner does a lot of work on suspension and engines for guys in this area that track or autox their cars. He has set up several cars for me for autox and he is also corner balanced this car for me, so I trust his opinion. Both of us felt that the noise was not coming from the panel behind the seat and he felt confident that it was not a suspension component.
I purchased this car with a 1012 miles on the odometer and it was suffering from the delaminating roof problem that has been widley talked about here and other forums. The car now has 5300 miles on the odometer and I wonder if the time spent driving the car with the defective roof panel could have caused additional stress on the frame. The roof panel was fixed at about 1200 miles.
I did not know you could tour the dana plant and this is great information for me, thanks again. I will try and get there late this week or early next armed with my camera and notebook.
Call ahead on the tours, they may just be organized thru the NCM...
 

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Discussion Starter · #16 ·
Thanks, I have made contact with their engineering department to see if they had any diagrams they could e-mail that may help in my quest for answers. I may not need to make the trip.

Call ahead on the tours, they may just be organized thru the NCM...
 

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Thanks, I have made contact with their engineering department to see if they had any diagrams they could e-mail that may help in my quest for answers. I may not need to make the trip.
I wouldn't be surprised...they told us the frames are sold to GM for $3k. Pretty open to just about anything you asked.
 

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I would never let a hack at a dealership weld anything on my car. particularly aluminium. These guys can screw up an oil change. Go to a specialty welding shop if you need the repair. If they weld it I will assure you it will break again , and then you have a big mess on your hand.
 

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Went to the dealer today and discovered some very disheartening information. According to GM's Document ID:2257485 all 2005-2010 corvettes may be affected by this problem. As listed on the document:

Condition/Concern:

Some customers may comment of a creak type noise in the rear of the car. This noise seems to be induced as the body of the vehicle flexes. An example of this would be turning into a parking lot where the entrance has an incline.

Recommendation/Instructions

Note: Prior to performing the procedure below, be certain that the noise is not related to any suspension components or the panel behind the seat. Common areas of noise can be the rear stabilizer links or "oil canning" on the panel behind the seats. Technicians should isolate the rear body panel behind the driver's and or passenfer's seat to determined if the noisse can be reduced. If the noise is corrected the panel is "oil canning" and transmitting the noise. Oil can noise can be reduced by adding a small crease in the metal to reduce panel movment or adding several dimples to add rigidity to the panel. If the noise is not suspension related or the body panel, it may be necessary to continue with this PI.

Remove the fuel tanks and inspect the frame on both the left and right side of the vehicle. If a void is found, it will be necessary to re-weld this area.

Important: When MIG welding, it will be necessary to use all safety precautions since the area of concern is near the fuel tank(s).

Grind this area clean were welding is needed.
MIG weld area utilizing all safety precautions.
After welding is completed, coat area with rust inhibitor to prevent future corrosion.

Re-evaluate vehicle.
Caution: To avoid personal injury when exposed to welding flashes or to galvanized (Zinc Oxide) metal toxic fumes while grinding/cutting on any type of metal or sheet molded compound, you must work in a properly ventilated area, wearing an approved respirator, eye protection , earplugs, welding gloves, and protective clothing. This information was taken from SI Document 824779. Use labor operation S0017 if welding of the frame is required.

I gathered some of this information from this thread:
Any safety issues w C6 Z suspension ?
I updated the numbers on the document to reflect what GM is showing today. I am in disbelief that this problem exist and yet GM seems to have done nothing to correct it. This updated bulletin just extends the years of affected vehicles up thru 2010.
It is also worth noting that the 2004-2009 XLR and V series are also listed on the document.

Please if anyone else has experienced this problem make it known here.

I am taking my car in on Wednesday to determine if the frame actually needs welding or if it is another issue as described in the document.
Thank you for posting this. This is EXACTLY what I am experiencing. Took my car to Nimnicht cheverlot and after spending 2600, 2 days later the noise is still there. GRRRRR. Found this post and this is exactly what is happening. Trading the car in soon and hope this is not going to be a problem.
 
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