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Sunday, August 31, 2014

Defective low density SMC and Corvette C7 Stingray misaligned bumper problems

As already mentioned previously, there are two impacts resulting from +General Motors  failed attempt to create a light weight SMC material used to make majority of Stingray and Z06 body panels.  One impact is the awful paint quality so common to the newest Corvette, regardless of production date.  However, the other effect should not be overlooked either as it is certainly easy to see.

Since the defective SMC is considerably weaker than its high density predecessor, it is highly prone to breakage.  This breakage is not of accident variety, it happens during Stingray assembly.  Urethane bumpers typically show certain degree of dimensional variation, a very common occurrence with injection molded plastic parts, due to shrinkage factor. 

Typically, these variation can be eliminated through adjustment of adjacent panels, applying certain amount of force to make the panels fit.  This approach was a standard issue on the previous generation of Corvette.  A good example of this situation were the front bumper clips popping out after a while, due to tension. 

For this generation of Corvette, things have changed however, the new material is very weak, it is brittle and it cracks under stress considerably lower than in the previous generation.  Bowling Green management already figured out this part, as evidence by hastily epoxied front fender mating surfaces on numerous cars (not visible until front bumper is removed from the car).

Apparently no chances are being taken with rear bumpers and instead of forced fitment that most likely would result in cracked quarter panels, +General Motors decided to release the cars with misaligned bumper than risk more cracked panels that could be visible in the case of rear bumper.

General Motors of course counts on apathy and lenience of the buyers, with most of them remaining under impression this misalignment is ACCEPTABLE. 

However, those few that complain, end up with their cars being bought back by GM.  Why?  Very simple actually, GM does not want the publicity and more evidence regarding the failure of new SMC material.  After all, should someone decide to align the rear bumper, chances are very good the quarter panels are either already cracked or will crack during this process.

One thing is certain, misaligned bumpers are a new rule for the Stingray, not an exception, just as demonstrated by this car.  Yes, this truly looks like shit and should not happen on a 20k car but somehow it happens daily on a 70k car.  Some bargain this new Corvette is...

2 comments:

  1. I have had a body panel gap issue from the beginning. Some gaps are larger than is specified in the service manual and the car just doesn't look right. All GM does is try to make me disappear. Another dealer tried once to fix it and failed. Other dealers will not try because of the history. I have had three contacts with the factory rep. The first time they told me to take it to the dealer. The dealer told me that the factory said would take care of it - result - no repair. Instead they referred me to a dealer sales rep - (to convince me there was nothing wrong with then vehicle). The second time, with a factory engineer present, they told me the gaps were within specs, but some clearly are not. They declared that the gaps were in fact within specs, and dismissed me. I filed a BBB complaijnt which resulted in a thirde factory tem visit. They reinspected the car, and five of us present witnessed the out of spec gaps. Then they said they "want to make me happey", so I was offered a trade-in/buy back that would have cost me $13,000! I refused their magnanimous offer then was told they were not going to repair my vehicle. Now it will go to BBB, then through the legal system.

    Thank you, GM!

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    1. Your problems will get worse with time, unfortunately because plastic and other composite parts go through heat related shrinking and expansion cycles, this is why bumper clips tend to pop out on Corvettes. I have never personally experienced GM willingness to admit there is a problem with Corvettes I had in the past. Hard to get anything fixed if GM refuses to admit anything at all.

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