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Old 12-22-2012, 09:48 AM   #370
Inferno
 
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Drives: Z06
Join Date: Apr 2009
Location: CA
Posts: 90
Quote:
Originally Posted by 68vert View Post
No, GM has the issues worked out. It was always a very small amount of cars affected.


Originally Posted by Chevy Cust Svc
Hello all,

LS7 Valve guide issue summary:
• Affects a small, number of '08, 09 ’10 and ’11 Z06’s
• GM discovered the condition through our cylinder head warranty data involving a very small percentage of our vehicles.
• Through inspection of returned heads, it was determined that a machining error in the valve guide had occurred at our head supplier.
• The quality issue has been contained as of Feb 2011 with 100% inspection of all heads.
• The most common customer complaint has been excessive valve train noise.
However if the condition is not addressed, it could result in engine failure. To date, where this condition has been observed, it has occurred early in the vehicle life.
What customers need to know: They should drive and enjoy their vehicles without fear. If their car demonstrates this condition, they are likely to hear unusual valvetrain noise first. If you have a concern regarding this issue on your personal vehicle feel free to contact me through private message on this forum and we will work to assist in resolving your concern. Feel free to contact me through Socialmedia@gm.com please put attention Evan in the subject. As always, vehicles that have modifications to the powertrain or the calibrations, are no longer covered by GM's warranty.

Sincerely,
Evan, Chevrolet Customer Service

From here : http://forums.corvetteforum.com/c6-z...confirmed.html
The specific failure has not been relayed, explained or delineated.

And GM has not figured out a way to evaluate or fix the existing bad ones until the motor blows up.....

To think you could evaluate valvetrain wear by listening to the degree of loudness of the valve train ticking noise is a bit far fetched.

Last edited by Inferno; 12-22-2012 at 10:11 AM.
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