Engine had excessive noise. After reading several Corvette complaints about improperly machined heads by general motor's supplier linamar, and that numerous vehicles have had valves drop and catastrophic engine failure, I had my car with checked at a specialty shop. I had several valve guides outside of service specifications. The car is being repaired with proper re-machining of the heads to make the valve guides concentric, new intake and exhaust valve guides installed, as well as new seals, valves, springs, etc. 88% of the Corvette forum members who have had their cylinder heads tested for excessive valve guide wear, were out of service specifications. Source: www.corvetteforum.com/forums/...-registry.html GM needs to issue a recall on this issue. There have been numerous engine failures as a result of a dropped valve into a cylinder. This stops the engine, power steering, and power brakes which can cause accidents and fires. GM is very aware of this issue, but refuses to do anything about this huge safety risk to drivers, passengers, and nearby vehicles if the engine fails going down the road. Regards.

- Tucson, AZ, USA

I became aware of a potential valve guide wear issue with the LS7 and LS9 engines through the Corvette forum, the Corvette action center, and other sources. I began researching the issue and decided that I should have my car checked out at a GM dealership. It was determined that the valve train noise appeared to be normal and the engine was not burning or using any excessive oil. The more I followed the valve guide wear issue, the more concerned I became. That being said and the fact that the dealer had never heard of or had any customer come in for the issue I decided to have a local performance engine shop (because of their extensive LS7 experience) install a reworked set of heads with bronze valve guides with additional parts recommend by the shop, to fix the problem permanently, based on their knowledge with the issue. My original heads were evaluated for valve guide wear and 'every intake and exhaust valve guide was outside of the GM service bulletin service limit of.0037 with the #8 intake valve being so far out that it was deemed N/R (so loose it was too big for the gauge readout). The vehicle only had 7500 miles on it. 88% of the Corvette forum members who have had their cylinder heads tested for excessive valve guide wear, were out of service specifications. Source: www.corvetteforum.com/forums/...-registry.html GM needs to issue a recall on this issue, there have been numerous engine failures as a result of a dropped valve into a cylinder which can cause accidents and fires. GM is very aware of this issue, but refuses to do anything about this huge safety risk to drivers, passengers, and nearby vehicles if the engine fails going down the road.

- Plymouth, MI, USA

The engine exhaust valve guides were outside of GM specifications and both cylinder heads were replaced under warranty because of this. This defect can cause the head of a valve to snap off and destroy the engine. The engine will stop working immediately, causing the power steering and power brakes systems to fail. The valve failure can cause a oil spill onto the road if the engine is destroyed. There have been numerous engine failures as a result of a dropped valve into a cylinder which can cause accidents and fires. GM is very aware of this issue, but refuses to do anything about this huge safety risk to drivers, passengers, and nearby vehicles if the engine fails going down the road.

- Renovo, PA, USA

My son's car blew up while traveling on the freeway almost causing an accident. He will file a separate complaint. There is a systemic problem with the Z06 and the 427 engine so I had my heads checked as a preventative measure and they were far enough out of spec that self destruction was imminent. The heads were checked and replaced by a Chevrolet dealer. There are hundreds of examples of this problem on the Corvette forum and it's only a matter of time before someone gets seriously injured. I sincerely hope you will look into this problem in time to perhaps save someone's life.

- Oakhurst, CA, USA