I was concerned about a noise that I was hearing in my 2006 Z06 that is unlike any other noise I have heard while currently owning my three other GM vehicles. I decided to bring it to a well know corvette speciality shop near me. The told me about the valve guide issue that has been linked to the LS7 heads. I immediately told him to take the heads off the car and check them. I had 4 exhaust valves that were way out of GM specs. I had the heads re-machined properly and installed new intake and exhaust valve guides, valve springs and seals.

- San Leandro, CA, USA

I was driving down a busy street at 35 mph in heavy traffic and heard a metallic sound. The engine locked up and the rear end skidded till I put in the clutch and coasted to a parking lot. I was aware of the valve problems so I took the head off the engine and sure enough dropped a valve taking out the piston and breaking the block. I took the car to kool Chevy and was told in would cost 22,000 dollars to fix it. Kool told me GM would not cover any of it because the car was out of warranty at 59,000 mile on the car. I could not afford to fix the car so I sold the car as is losing more than half what the car was worth. I am still sick about this a year later as I will never be able to have another car like this. I feel like GM should have worked with me as this was a known problem with the LS7 engine. If this would have happened at highway speeds it would have been a lot worse than it was. Lost power steering, power brakes, and skidded when the engine locked up.

- Wyoming, MI, USA

The contact owns a 2006 Chevrolet Corvette. While driving at any speed, the engine shook and the harmonic balancer wobbled. The failure recurred several times. The vehicle was taken to the dealer where it was diagnosed that the harmonic balancer needed to be repaired. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 6,100.

- Coral Springs, FL, USA

Any quick search of the web will show that this car engine, the LS2 or 6.2 L engine has had a defect that GM has denied over the years and fails to stand behind after warranty; crank shaft pulley wobble and worn rubber gaskets on the harmonic balancer of the 2006 model year. Tech bulletins have been issued and this topic of pulley wobble and rubber gasket failure and is quite the talk on various Corvette forums. Since I am well behind warranty, I had to have this diagnosed through my licensed certified auto mechanic. This repair requires extensive labor time to repair. Scared to see the bill tomorrow. GM's response is I should of taken it to an authorized Chevy dealer. That is hog wash because should I had done that, I would probably still had to pay their exorbitant labor costs and still not be covered on this serious engine defect. In fact, I believe GM has re-designed the part so what does that tell you. Failure to fix will just harm the engine for the future and replace belt after belt when the true problem is ignored by

- Mickleton, NJ, USA

Cruising at 50 mph on feeder ramp and dic showed engine power reduced for 2 seconds then boom!

- Humble, TX, USA

I bought this Corvette Z06 used from a private party. The engine had a catastrophic failure due to a known issue with the valve guides and valves in the LS7 motor from the factory. I was driving home from work when the motor failed. I was lucky to be only a mile from home when it failed and I was able to coast into my garage. The exhaust valve dropped and destroyed the #1 piston along with that cylinder, and the engine block. Nothing in the motor is salvageable as it bent or sent metal shards into every part of the motor. I have tried several times to get Chevy to help me with this motor, but they will not help at all. They know about the problem, but will not lift a finger to help anyone.

- Sacramento, CA, USA

Manufacturing defected in the LS7 motor. Upon further investigation I had my 2006 Corvette Z06 inspected for a loud audible tick in the motor. The source of this noise was from the in-balance from the #3 and #4 intake valves on the engines heads. There is premature wear on both valve guides causing internal failure to the motor. Under power demand the in-balance will cause the titanium rod to strike the sides of the valve seat causing the head of the valve to crack and fall into the cylinder. Once this occurs instant catastrophic failure of the motor happens resulting in white bellowing smoke from the exhaust, oil spillage, and engine lock resulting in the vehicle skidding off the road or loosing control. Fortunately for me I caught this in time before having a catastrophic failure. Both LS7 heads are being repaired and machined to meet industry standards. This problem must be addressed to all LS7 Z06 owners as it could and has caused several crashes and possible deaths. Once repairs to the LS7 heads are made the vehicle can be returned to service.

- Las Vegas, NV, USA

2006 Z06 corvette engine was making an unusual noise. After doing some research and the finding, it was determined that the valvetrain on the engine may be pending failure. The heads were removed and valve train tolerance checked to be found way out of serviceable limits. Thus requiring repair. This was considered excessive wear for such a low mileage vehicle that was pending catastrophic engine failure if the repairs to the heads was not performed. In doing additional research, this appears to be quite common for the Z06's 7.0L LS7 engine. Luckily my engine did not have a catastrophic failure because I took preventative measures at my own cost, but this design should be considered a failure and recalled. I was not going to risk a catastrophic engine failure possibly on the highway and put myself and others at risk. Please investigate.

- Homer Glen, IL, USA

The exhaust valve broke and destroyed the motor

- Cape Coral, FL, USA

Date of heads pulled: 7/5/12 head type: GM LS7 year: 2006 miles: 16,000 track time: None tune: Stock I had my cylinder heads removed because I was paranoid after reading online about many other owners having issues with their valve guides being out of spec. My cylinder heads had valve guides that were way out of spec and the car only had 16,000 miles on it and was never tracked or abused. These were on the verge of having the valve break off and seize the motor which could have resulted in serious injury to myself and others around me while driving. I paid out of my own pocket to have these heads redone. Max allowable clearance is 0.0037 for both intake and exhaust. Valve guide clearances intake #1 top.0027 mid.0021 bot.0024 intake #2 top.0030 mid.0022 bot.0028 intake #3 top.0025 mid.0022 bot.0023 intake #4 top.0030 mid.0023 bot.0025 intake #5 top.0033 mid.0022 bot.0027 intake #6 top.0028 mid.0022 bot.0025 intake #7 top.0029 mid.0023 bot.0027 intake #8 top.0030 mid.0023 bot.0028 ========================= exhaust #1 top.0022 mid.0026 bot.0069 exhaust #2 top.0022 mid.0024 bot.0048 exhaust #3 top.0020 mid.0028 bot.0064 exhaust #4 top.0022 mid.0024 bot.0039 exhaust #5 top.0021 mid.0029 bot.0085 exhaust #6 top.0021 mid.0023 bot.0046 exhaust #7 top.0021 mid.0024 bot.0054 exhaust #8 top.0022 mid.0025 bot.0033.

- Coplay, PA, USA

I started the car when it was cold, it began to squeal from the belts. I gave it a small rev and it squealed intensely, I mean very loudly! I opened the hood and belts were not moving. I could not move the car. The harmonic balancer had lost it's bond. I am just glad I was sitting still. At speed, the steering would have been lost, it could have killed me! I had the car towed to the shop, and it cost me $1000. Not good! I read that this happens alot. Bad design for sure. I should be reimbursed. What can I do? Chevy won't even talk to me about it. It's a shame because I love my car, but now I am afraid to drive it!

- Myrtle Beach, SC, USA

My son was driving and just completed a turn when he applied the accelerator and the engine stopped abruptly. There was a cloud of smoke and then a small fire underneath the car from the oil that came out from a baseball size hole in the side of the block below the number 8 cylinder. Upon further investigation, a valve in the number 8 cylinder snapped below the valve guide dropping the head of the valve onto the piston which caused the failure. I have the engine available for inspection.

- Carrollton, TX, USA

Hello, I am reporting on my 2006 C6Z06 corvette that recently had the valve-to-guide clearances checked on my engine and my measurements are beyond the serviceable specifications on 8 out of 16 valves, both intake and exhaust. I consider this a safety hazard due to the fact that if the vehicle is driven and engine seizes, loss of control may occur. I also have what appears to be a leak on the fuel module/sending unit, specifically on the top plastic elbow connector. I have strong gasoline odor in the cabin of the car and visible gasoline from the underside of the car near the fuel tank.

- Austin, TX, USA

I was concerned about excessive valve train noise and after reading several accounts of improperly machined heads by GM's supplier linamar, and that numerous vehicles have had valves drop, resulting in engine failure. As a result, after having been rebuffed by Chevrolet, I took my car with 36,000 miles on it to a Corvette specialty shop to have my valve guide clearance tested. I had several exhaust valve guides outside the maximum service specifications, indicating that a catastrophic engine failure was imminent. The car was 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 which can cause loss of steering, braking capability, and which can result 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 while the vehicle is underway on public roadways.

- Ooltewah, TN, USA

The cylinder heads at 69K miles were checked due to excessive valve train noise and the valve guides and one intake valve were found to have clearance more than double the service tolerance.

- Kingston Springs , TN, USA

The harmonic damper on 2006 Corvette with LS2 engine failed resulting in power steering drive belt coming off pulley causing loss of power steering. The high effort required to steer vehicle almost resulted in crash. This harmonic damper issue is documented in numerous internet forums and is believed to be a widespread issue that should be recalled and corrected by the manufacturer.

- Perkasie, PA, USA

According to Corvette forum, this is another widespread problem- the harmonic-balancer becomes warped and requires replacement... if not done timely, other "parts" could be negatively impacted as well...

- Brookeville, MD, USA

Noticed a loud ticking from valve train. Had heads removed and found exhaust valve guides were out of specification after 11,000 miles by 50%. had to do valve job on heads because Chevy denied claim. Now a recall out for 08 and newer but no coverage for 2006 and 2007!

- Peoria, AZ, USA

I was driving back home from lunch with a friend I haven't seen for a while, car ran flawlessly up to the loss, dropped him back off at his car and we parted ways. Then on my way home, making a left hand turn, going about 40mph, 3rd gear cruising along all of a sudden the car sounded like the exhaust came loose, followed by a lot of engine noise, followed by a large white puff of smoke from behind. I had a extended warranty that was by Mercury and they denied the warranty due to abuse. Went to a race event 3 months prior and did 3 races on a straight away from 50-130, found footage of my car on youtube and they claimed that was the reason why I blew my motor. They said I either had to deny that and risk getting charged with fraud or admit that was me in the video. This will definitely be the last GM I ever buy. Now left with a useless car and having to pay out of pocket for a new motor.

- Lake Forest, CA, USA

Massive engine failure due to a failed exhaust valve after inspection, car lost all power and was immobile after rolling to a stop. The 7 and 8 cylinder on the block were completely ventilated. This is a very common problem with 2006-2011 corvettes and many others have had the same issue.what happens is the head of the exhaust valve falls off and then it makes contact with the piston and takes out the block and piston and rods. Please investigate this as there is several hundred or more Z06 equipped with the LS7 motor that has had the same issue. It is a safety concern and imho there should be some kind of recall on these motors.

- Sioux Falls, SD, USA