By on October 15, 2015


A group of owners of 7-liter V-8 powered, 2006-2014 Chevrolet Corvettes have filed a proposed class-action lawsuit against General Motors claiming those models have excessive valve guide wear that leads to engine failures.

The filing, which was made Wednesday, said General Motors is aware of the problem, but has yet to come up with a solution.

The 19 owners have filed more than 70 claims, “including violations of the RICO Act, unjust enrichment, negligence and fraud,” reported Law360.

GM began testing vehicles using the “wiggle method,” said the owners, and when the test found many of the cars had valve guides out of spec, the automaker dropped the test because it “would lead to more repair and investigations than it wished to perform.”

This isn’t the first time this year the Corvette has been in the spotlight due to engine failures.

In July, Gary Gastelu of Fox News experienced an engine failure in the current-generation Chevrolet Corvette Z06 powered by the new LT4 V-8. Earlier in the year, owners were experiencing engine failures at under 1,000 miles on the clock.

In response, General Motors instructed owners to follow the break-in period and change their oil at or before hitting 500 miles.

“We now encourage all owners to change their oil at 500 miles to remove possible contaminants created during the engine break-in process. And, as always, we encourage the use of Mobil 1 synthetic oil – which is a factory fill for all Z06 models, and Stingray Z51 models – and encourage owners to follow the engine break-in process detailed in the owner’s manual,” said Monte Doran, a spokesman for Chevrolet.

During Motor Trend’s “Best Driver’s Car” test this year, the Corvette Z06 finished dead last — or not, as MT placed it as a DNF — due to performance issues.

“It didn’t work. The damn Z06 retarded spark by 8 degrees, and the 1.7-liter TVS supercharger refused to make boost. No one knows why,” said Motor Trend’s Jonny Lieberman.

General Motors blamed the lack of performance on “bad gas”, but all cars in the test received their fuel from the same source.

Get the latest TTAC e-Newsletter!

36 Comments on “Chevrolet Corvette 427, Z06 Owners File For Class Action Against GM...”

  • avatar

    Is this article about LS7 lawsuits (as the title suggests), LT4 failures, or 6th and 7th generation wide body Corvettes in general?

    It might just be me, but when you highlight a car’s failing at a magazine test, such as Motor Trend’s, you could also mention how it performed at other such tests such as Car and Driver’s Lightning Lap.

    Not doing so makes you seem biased. Maybe you are, but most here given complete information can make up their own minds.

    More information is always better for the reader/consumer.

    • 0 avatar

      So, for all the faulty ignition switch GM cars, should we also mention all the GM vehicles without a faulty switch?

      There is no bias here. Mentioning the LT4 is adding context. Supposedly, the LS7 is bulletproof and the engine that replaced it in the Corvette, the LT4, has some serious issues needing attention. However, it seems the LS7 might not be as bulletproof as everyone thinks.

      Or this might just be a frivolous lawsuit. Time will tell.

      • 0 avatar

        “So, for all the faulty ignition switch GM cars, should we also mention all the GM vehicles without a faulty switch?”

        If that’s the meaning you took from my statement than there isn’t much left to say.

      • 0 avatar

        Bulletproof is a matter of reference LS7 (and as I hear it LS9 heads as well) valve guide issues aside the engines are fine naturally aspirated but don’t tolerate a serious amount of boost well. The primary culprit is squeezing 7 liters from the LS block which required fairly thin bores and bore liners so the block could be machined using LS bore centers.

        If you see someone touting a 1000hp C6 Z06 chances are it is using something other than a stock block to accomplish the goal.

        I’m not sure what is causing the valve guide wear as GM went to great lengths to reduce geometry issues that would cause side loading on the guide and shorten the life of the guides on the standard engines but its always possible as the LS7 uses just over 15mm of valve lift along with an offset rocker arm and revs to 7,000 rpm with a large 56mm diameter titanium intake valve and a 41mm sodium filled stainless exhaust valve in combination with a hydraulic roller valvetrain.

        GM guys don’t like to hear it but that’s about as far as your going to see a high revving big valve cam in block factory engine go with any kind of real longevity and even then it appears there are issues. Its been commonly accepted that over more than about 13mm of valve lift and revving more than 6000 rpm really starts to cut into the life of the engine, especially if the ramp rates on the cam lobes get aggressive (I’m not sure if GM is using an asymmetric lobe with an aggressive opening flank on the lobe and a slower closing rate to stave off float and wear on the valve) but on the LS7’s big bores and excellent port design it is competitive with many four valve heads when it comes to low and mid lift flow capability and by jamming the valve open as quickly as possible the engine can take advantage of that and broaden its power without resorting to variable valve hardware.

        • 0 avatar

          Exactly; Stock, the valvetrain of the LS7 was very aggressive to get that much airflow, and that comes at an expense. In addition, unless it’s properly treated or coated, and kept very clean, Titanium loves to gall on other metals (such as the valve guides), which will only accelerate their wear

      • 0 avatar

        Frivolous ???? Are you joking ?? What ls7 knowledge do you have
        Obviously zero no one thinks the ls7 is bulletproof

        Think before you speak

  • avatar

    That tree no longer exists. I think somewhere I have a picture of me in my car right about there.

  • avatar
    Big Al from Oz

    Why doesn’t GM just come out with a modification for a repair?

    For GM to make such a radical change to the it’s servicing schedule proves there are real problems that require resolution.

    People not familiar with tracking wear/failure of mechanical components should realize there is a run in phase, normal operation phase and failure phase for most every component.

    A 500 mile oil change is radical and does highlight during the run in phase there is some serious wear occurring considering there is enough contaminants to destroy an engine. Seems like this engine came out of the 1930s.

    I wouldn’t buy a Corvette with this engine if you paid me. I wonder what the life of the engine is if you follow the manufacturer’s servicing schedule?

    10k, 30k, 50k????

    • 0 avatar

      If you paid me, I would take this Corvette. The money that you paid me would offset any possible issues with the engine. In the meantime, I’d have a 650 HP supercar to drive around.

      • 0 avatar


        Pay me to take it and I’m game even if the engine has already blown.

        I’ll just pocket the money, sit in the car and make “vroom vroom” noises for a while, then yank the engine and turn it into an awesome coffee table.

        Then I’d sell the carcass to somebody else who wants to put an engine in it.

        You’re a sucker if you would turn down a free Corvette plus cash.

      • 0 avatar

        And if they didn’t pay you, you would take a Shelby Mustang even though it’s not A-plan eligible, I’ll bet. And I wouldn’t blame you.

        And if you are as smart as I think you, they would have to pay you a lot to take the non-Ford option.

    • 0 avatar

      I think one of the issues is that people actually drive Corvettes and expect them to be reliable. I know a lot of people who own and DD them. Many people who buy a Ferrari or Lamborghini use them occasionally and are not surprised when they break. I have friends with other new supercars that are constantly complaining of things cracking, breaking or just not working. These are the same people who previously owned different supercars and complained about them breaking on the way to the track.

      When you buy a Corvette, you think that you are buying a supercar chassis with a proven, old technology, pushrod engine that has been around in some form longer than many of us. People think they are buying a truck powertrain in a lightweight car, and driven reasonably, they expect them to last virtually forever.

      That is not the case. They are highly tuned and do not last forever. Do they last a comparable length of time to comparable cars?

    • 0 avatar

      The 500 mile oil change is only the initial one. The oil used is a special break in oil and is to be removed at 500 miles. There are instructions on how to drive the vehicle during the initial period as well. My 2003 Honda has the same procedure. With very tight tolerances in modern engines proper mating of the surfaces is critical for performance and durability.

      • 0 avatar

        You aren’t supposed to change your break in oil early (typically 5000+ miles). Honda doesn’t want you to change it until the maintenance minder tells you to. Honda has all their maintenance schedules on their website. The earliest you first service is 7500 miles. That includes the S2000.

  • avatar

    Invoking the RICO act? Hilarious.

    If this were to be ruled on wouldn’t that open GM and Volkswagen up for criminal charges in their scandals?

    • 0 avatar

      Do you mean organized fraud isn’t a crime? The 140+ cases of manslaughter due to the faulty ignitions weren’t crimes? Maybe this sort of thing needs to happen. Corporate execs actually thrown in jail for these crimes.

  • avatar

    Change the oil at 500 to remove contaminants? Valve guide material is definitely a contaminate LOL!

    • 0 avatar


      That reminds me of an old MotoGP joke. When an engine grenades they will call it an “electrical failure”. I suppose that is true if an exploded crankshaft or rod through the block actually damages one of the charging components lmao.

  • avatar

    “During Motor Trend’s ‘Best Driver’s Car’ test this year”

    That sucks that the Corvette didn’t work properly for MT’s comparo, but that has to be the worst comparo of 2015.

    No Viper ACR. No Mustang, in any form. No Huracan. No McLaren. No 488GTB. Instead, two Cadillacs and two Mercedes. Great work Motor Trend…

    • 0 avatar

      Scuttlebutt in my neck of the woods has always been that the MT car of the year always went to either the largest advertiser, or the company that used the most grease on the selection committee.

      Sometimes their choices weren’t bad anyway, but other times over the years they have been so far off base as to be laughable.

      Your point about this year is an excellent illustration.

  • avatar

    I owned a C6 Z06 for about 4 years and read about this with interest. I could never tell if this was a serious problem or a few complainers, but it looks like they’ve gotten enough onboard to make it more serious that forum bitching.

  • avatar

    I call BS on “premature valve guide wear causes engine failure”. If, that is, “engine failure” means what I expect it to mean; i.e., catastrophic failure that prevents forward motion and requires major overhaul. Valve guide wear should cause excessive oil consumption, visible especially on deceleration. If your new Vette drops a cloud of blue smoke at each trailing throttle decel, you need to start checking the oil.

    Also, I don’t see the linkage between premature valve guide wear and early oil changes to remove debris supposedly generated during break-in.

    And finally: “General Motors blamed “bad gas” on the lack of performance…” I have never heard of a poor performing car turning the gas bad.

    • 0 avatar

      “I don’t see the linkage between premature valve guide wear and early oil changes to remove debris supposedly generated during break-in.”

      There is no connection. They are two different issues with two different engines. The connection is they are in the same car. That is all.

      “And finally: “General Motors blamed “bad gas” on the lack of performance…” I have never heard of a poor performing car turning the gas bad.”

      Yeah, got that backwards. Thanks for the catch.

      • 0 avatar

        What about changes in oil chemistry? I wonder if the lack of zinc in modern oils has anything to do with accelerated valve guide wear? Although some manufacturers use a special break-in oil that is high-zinc from what I have read.

  • avatar

    They should be thrilled this is all that is happening to them, guy down the road from me, his C6 Z06 caught on fire in his garage last year and burned his house down and all his cars. Surprisingly he just bought a new C7 Z06 with the Z07 package which I thought was a brave move.

  • avatar

    I wonder how much of the metal debris could have been taken out of circulation with a simple magnetic oil drain plug?…

  • avatar

  • avatar

    now the vette REALLY is like an european sport car!!

  • avatar

    In the interest of facts, any and all issues involving Corvette are not always the same. The questions can be substantial, especially when comparisons are made between vehicles, engines, driving habits and break in process once the vehicle is purchased.
    There is no 2 Corvettes that are driven the same, maintained the same and not everyone reads an owners manual about proper break in procedure.
    Even back in 2006 when ZO6 and LS7 was introduced, there was a break in process in the owners manual.
    Are the Corvettes modified??? Are they stock???
    Generation 5 small block oil filter debris is acknowledged and known. 500 mile oil change was for MUCH more than just debris, it was also known about the aeration of the oil due to antifoaming agents.
    LS7 Generation 4 small block is an entirely different animal, from compression to valve train specifications to fuel delivery in comparison to Generation 5 small block, LT1 or LT4.
    Lets wait and see, lets educate on the facts and watch where it goes.

  • avatar

    And about the Motortrend thing,

  • avatar

    See Vette go!

    See Vette go fast!

    See Vette go BOOM!

    Maybe they were designed to be driven to Cars and Coffee, and not to be driven hard. Otherwise, why no MT? But those damn customers keep wanting to push them hard anyway.

    What do they think it is, anyway? A sports car?

    Poor Zora Arkus-Duntov must be turning close to 7K rpm in his grave.

    Which is more than the new Vettes seem to be able to sustain.

Read all comments

Back to TopLeave a Reply

You must be logged in to post a comment.

Recent Comments

  • Lou_BC: “Neither are not stagnant” ??? Ditch the “not” or the “N” in Neither.
  • EBFlex: “I will stump yet again for PHEVs which require about 7x less battery capacity, charges well on 120v,...
  • Lou_BC: Those of us in Canada and the USA have lived our lifespans with cheap and easily accessible energy. Europeans...
  • brn: What’s with the downer of a headline? 24% are “very likely”, is an impressive number. An...
  • 28-Cars-Later: There is no more rule of law.

New Car Research

Get a Free Dealer Quote

Who We Are

  • Adam Tonge
  • Bozi Tatarevic
  • Corey Lewis
  • Jo Borras
  • Mark Baruth
  • Ronnie Schreiber