C5 Fender issues
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Advanced
Joined: Dec 2013
Posts: 79
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From: Akron OH
C5 Fender issues
Has anyone had or have this problem? Paint started to look as getting stress marks on front fenders only, body man sanded them down and the cracks were in the fender material itself. So far he was able to save one fender but I had to purchase one. The paint is original car Has never been resprayed.
Melting Slicks
Joined: Jul 2010
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From: McGrady NC
St. Jude Donor '15-'16
That looks perhaps like a defective fender that has finally started failing, letting the crack or separation work through the paint layers. Are you sure he car has never been in a fairly significant front end wreck? Perhaps body stress from a hard pot hole bounce? Or being jacked up at a point in the wrong place can put odd stresses on the body. Just guessing at this point as I've never see such a problem.
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That does look like stress cracks have developed but with that low mileage it's hard to imagine it happening.
Racer
Joined: Feb 2001
Posts: 298
Likes: 1
From: San Antonio Texas
We have just over 115k on our C5. One fender has been replaced due to collision damage and the other is factory original. Neither have had any cracks like this. I haven't seen anything like this any of our friends' C5s. They certainly do look like stress cracks that have now shown up through the paint....
Intermediate
Joined: Oct 2014
Posts: 45
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From: az./ut. border
Look @ the mounting holes to determine if it has been pushed back. It may have been an attempt to adjust hood/fender gaps. These will come back without grinding & laminating. I know this, I do this for a living.
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Drifting
Joined: Mar 2013
Posts: 1,496
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From: Little Rock Arkansas
I agree with the stress crack issue and this post...
... is likely alluding to what the issue is. I'll explain.
The C5's fenders, in a bit of an oddity sort of design compared to other cars, is made out of RRIM urethane. This is the same material that the front and rear fascias are made out of. They are not SMC, like the doors, rear quarters, and other harder body materials are made out of.
The reason why the front fenders at first glance appear so rigid, SMC in style, and not the same as the fascias is because of the underlying fiberglass inner wheel well. This large piece is actually the real structural portion of the fender. The proper orientation of the inner fender liner is key and can determine a lot of things, not only structural integrity of the fender but also if the hood is sealing properly along the side and if the surrounding body pieces are lining up properly.
My assumption to why you are seeing those sort of cracks in the fender is because the inner liner is causing issues. What that issue is would be difficult to determine without seeing it in person. It could be out of position and causing the fender to compress against it. How it would arrive to that point would also be questionable and it may be difficult to determine if this is so as alignment of the other body panels can throw initial visualization off. Maybe there is a portion of it loose - it is "glued" to the chassis - causing it to wobble against the back side of the fender and stress the paint.
The orientation of the cracks are similar to cracks that appear when C5s are involved in low speed fender benders where the fender compresses against the inner liner. If you've ever seen that happen, the fender doesn't crumple or disorientate, but rather it develops large cracks as it compresses the inner liner. That's obviously not saying your vehicle has been in an accident since you have reinforced that is the case, but it points to an underlying issue.
I would suggest that you have the body person check the inner fender liner. Not necessarily it's position, but rather that it is still installed properly. This may require you to have an experienced individual that has performed C5/C6 body work come in and look at it, as proper position of the fender liners can be an issue for body technicians not experienced with them.
The C5's fenders, in a bit of an oddity sort of design compared to other cars, is made out of RRIM urethane. This is the same material that the front and rear fascias are made out of. They are not SMC, like the doors, rear quarters, and other harder body materials are made out of.
The reason why the front fenders at first glance appear so rigid, SMC in style, and not the same as the fascias is because of the underlying fiberglass inner wheel well. This large piece is actually the real structural portion of the fender. The proper orientation of the inner fender liner is key and can determine a lot of things, not only structural integrity of the fender but also if the hood is sealing properly along the side and if the surrounding body pieces are lining up properly.
My assumption to why you are seeing those sort of cracks in the fender is because the inner liner is causing issues. What that issue is would be difficult to determine without seeing it in person. It could be out of position and causing the fender to compress against it. How it would arrive to that point would also be questionable and it may be difficult to determine if this is so as alignment of the other body panels can throw initial visualization off. Maybe there is a portion of it loose - it is "glued" to the chassis - causing it to wobble against the back side of the fender and stress the paint.
The orientation of the cracks are similar to cracks that appear when C5s are involved in low speed fender benders where the fender compresses against the inner liner. If you've ever seen that happen, the fender doesn't crumple or disorientate, but rather it develops large cracks as it compresses the inner liner. That's obviously not saying your vehicle has been in an accident since you have reinforced that is the case, but it points to an underlying issue.
I would suggest that you have the body person check the inner fender liner. Not necessarily it's position, but rather that it is still installed properly. This may require you to have an experienced individual that has performed C5/C6 body work come in and look at it, as proper position of the fender liners can be an issue for body technicians not experienced with them.
Thread Starter
Advanced
Joined: Dec 2013
Posts: 79
Likes: 10
From: Akron OH
I agree with the stress crack issue and this post...
I will ask my body man if he knows about the liner, I would hate to have the same thing happen to the new fender.
... is likely alluding to what the issue is. I'll explain.
The C5's fenders, in a bit of an oddity sort of design compared to other cars, is made out of RRIM urethane. This is the same material that the front and rear fascias are made out of. They are not SMC, like the doors, rear quarters, and other harder body materials are made out of.
The reason why the front fenders at first glance appear so rigid, SMC in style, and not the same as the fascias is because of the underlying fiberglass inner wheel well. This large piece is actually the real structural portion of the fender. The proper orientation of the inner fender liner is key and can determine a lot of things, not only structural integrity of the fender but also if the hood is sealing properly along the side and if the surrounding body pieces are lining up properly.
My assumption to why you are seeing those sort of cracks in the fender is because the inner liner is causing issues. What that issue is would be difficult to determine without seeing it in person. It could be out of position and causing the fender to compress against it. How it would arrive to that point would also be questionable and it may be difficult to determine if this is so as alignment of the other body panels can throw initial visualization off. Maybe there is a portion of it loose - it is "glued" to the chassis - causing it to wobble against the back side of the fender and stress the paint.
The orientation of the cracks are similar to cracks that appear when C5s are involved in low speed fender benders where the fender compresses against the inner liner. If you've ever seen that happen, the fender doesn't crumple or disorientate, but rather it develops large cracks as it compresses the inner liner. That's obviously not saying your vehicle has been in an accident since you have reinforced that is the case, but it points to an underlying issue.
I would suggest that you have the body person check the inner fender liner. Not necessarily it's position, but rather that it is still installed properly. This may require you to have an experienced individual that has performed C5/C6 body work come in and look at it, as proper position of the fender liners can be an issue for body technicians not experienced with them.
I will ask my body man if he knows about the liner, I would hate to have the same thing happen to the new fender.
... is likely alluding to what the issue is. I'll explain.
The C5's fenders, in a bit of an oddity sort of design compared to other cars, is made out of RRIM urethane. This is the same material that the front and rear fascias are made out of. They are not SMC, like the doors, rear quarters, and other harder body materials are made out of.
The reason why the front fenders at first glance appear so rigid, SMC in style, and not the same as the fascias is because of the underlying fiberglass inner wheel well. This large piece is actually the real structural portion of the fender. The proper orientation of the inner fender liner is key and can determine a lot of things, not only structural integrity of the fender but also if the hood is sealing properly along the side and if the surrounding body pieces are lining up properly.
My assumption to why you are seeing those sort of cracks in the fender is because the inner liner is causing issues. What that issue is would be difficult to determine without seeing it in person. It could be out of position and causing the fender to compress against it. How it would arrive to that point would also be questionable and it may be difficult to determine if this is so as alignment of the other body panels can throw initial visualization off. Maybe there is a portion of it loose - it is "glued" to the chassis - causing it to wobble against the back side of the fender and stress the paint.
The orientation of the cracks are similar to cracks that appear when C5s are involved in low speed fender benders where the fender compresses against the inner liner. If you've ever seen that happen, the fender doesn't crumple or disorientate, but rather it develops large cracks as it compresses the inner liner. That's obviously not saying your vehicle has been in an accident since you have reinforced that is the case, but it points to an underlying issue.
I would suggest that you have the body person check the inner fender liner. Not necessarily it's position, but rather that it is still installed properly. This may require you to have an experienced individual that has performed C5/C6 body work come in and look at it, as proper position of the fender liners can be an issue for body technicians not experienced with them.
Drifting
Joined: Apr 2011
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From: Deerfield Illinois
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My Brother in Law had his brand new 2500 HD pickup in for and oil change at the dealer, in the morning, first one, and it fell off the lift and crushed the rocker panel. When he called they told him twice it was not ready, finally he said what the hell is going on I want my truck, much later in the afternoon, then they finally came clean, HOURS later.