Wiggle test on all valves showed all exhaust valves with excessive guid where....safety issue....!!! this can and has led to catastrophic engine failure at freeway speeds.......

- Seattle, WA, USA

I took my car to american heritage performance in California and had the heads checked and they were all out of speck, at 16000 miles, and this car was only street driven, and had to have all this work done on a low mileage car was very upsetting, and in the end finding out that many cars have this problem. Having to get all this work done on a virtually new car is ridiculous..

- Oyama,Lakecountry B.C. Canada, AZ, USA

When I purchased the 2007 Corvette Z06, I was instructed to have the heads checked for excessive valve guide wear. I had the heads pulled and the valves examined by a local expert. He indicated that the valve guides were out of specification and needed replacement. I replaced these at my own expense of over $2000. Had the engine blown up as a result of this defective condition, the breaks and power steering would fail causing an accident. I would like GM to issue a recall on this model corvette.

- Sachse, TX, USA

At only 21,179 miles, my dealer inspected both cylinder head banks and found valve guide clearance to be well out of maximum allowed specification. This defect puts undue stress on the hollow, sodium-filled exhaust valves. If an exhaust valve breaks, the exhaust valve will drop into the combustion chamber, and cause a complete, catastrophic failure of the engine. This causes hazardous conditions for the driver, passenger, and surrounding traffic: The drive wheels may become locked as the engine seizes and the engine block may become windowed by a rod, causing a large spill of oil and coolant immediately under the vehicle on the roadway. These conditions could lead to a severe accident from a sudden spin and/or a fire. I have little confidence that the cylinder heads replaced on my car are free from the valve guide clearance defect. As more owners have become aware of the problem, replacement cylinder heads have been measured before installation on the engine and have been found to have defects in valve guide clearance and valve guide to seat concentricity, such as what could lead to a dropped exhaust valve and an accident. The vehicles should be recalled and fixed before any more serious accidents occur. Although my vehicle did not fail despite having the defect, I have seen a video of a spin caused by the failure, I have seen pictures of a vehicle after a fire caused by the failure, and I have seen reports of approximately 35 failures; all from corvetteforum.com. Therefore I am concerned about my safety when driving the vehicle and I believe the NHTSA should investigate the matter.

- Colorado Springs, CO, USA

Abnormal valve guide wear in cylinder heads considering age and mileage of vehicle. Potential catastrophic engine failure from dropped valve if not addressed. Chevrolet should fix whether vehicle still in warranty or not as is believed to be poor quality control resulting in machining errors.

- Taylorsville, NC, USA

Exhaust valve broke due to valve guides being out of spec. Engine seized. Immediate loss of power steering and brakes due to seized engine.

- Ramsey, MN, USA

My cylinder head intake and exhaust valves were severely out of GM's.0037" maximum wiggle tolerance. The valves were tested by yuma auto and trans as well as american heritage performance (harbor city, ca). Not addressing the issue may have caused a dropped cylinder valve and blown engine.

- Lexington Park , MD, USA

This car intermittently locks the steering column. No reason. The engine shuts off at speed.

- Brighton, MI, USA

Submission from constituent re repairs on his 2007 Chevrolet corvette (the engine "dropped a valve") the consumer was informed, the entire engine needed to be replaced at a cost of $18,722. Instead of replacing the engine, at no cost to the consumer, General Motors offered to pick up 45% of the cost, leaving the consumer to pay the balance of $10,630. The consumer stated GM issued an internal bulletin as far back as February 2008, that showed they were aware of the Z06 engine failures and short life expectancy.

- District Heights, MD, USA

Valves broke. Causing smoke and oil released on the highway. Valve guides broke. The engine heads failed causing an accident and a fire to the engine.

- Los Angeles, CA, USA

Exhaust valve guides are excessively worn beyond service limit. Approximately 4 times service limit. This is a definite safety hazard to me and to those around me. The worn valve guide causes the exhaust valve to stretch, and eventually break. When the valve head breaks, it beats its way out of the engine, causing potentially: Engine lockup, oil spill on highway, large smoke cloud and debris out the rear of the vehicle. Loss of control of the vehicle imminent danger to those around me due to loss of vision and slippery roadway. This issue affects all 2006 to 2013 Chevrolet Corvette Z06.

- Santa Fe, TX, USA

It is stock and no tune verified by ( reliable Chevrolet in springfield mo. And show-me speed in nixa mo.) at 49562 mile it drop the #6 exhaust valve which in turn destroyed the motor I have had this car to 3 different shops and they are all saying the same thing excessive wear on all the exhaust valve guides 2 of the shops determined this wear caused the exhaust valve to break other shop couldn't say.

- Ash Grove, MO, USA