By on August 22, 2015

2015-Chevrolet-CorvetteZ06-003-sm

Last time we heard from Fox’s Gary Gastelu, he was reporting that his test Z06 gave up during his track run in a spectacular shower of oil and grease and bits and fun.

Now, he says Chevrolet has told him what went wrong and it’s a familiar story:

After bringing it back to Chevrolet HQ for inspection, the engineers determined that the likely cause was a piston connecting rod bearing that was damaged by debris in the oil that was left behind after tapping the threads for the oil filter. Once a piece gets jammed in there, it starts creating more debris, which keeps making things worse until finally … kablooey. In this case, it took out a few more pistons with it.

Chevrolet says that the number of affected engines are in less than one percent (they all seem to be early engines, with contaminated oil and fewer than 2,000 miles) of all Z06 cars.

Gastelu said the tester Corvette he drove never received the oil change after 500 miles that Chevrolet recommends to keep the engine from catastrophic failure. The cause for the failure may be thread shavings for the oil filter that may have made their way into the engine and circulated through the engine.

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66 Comments on “Chevrolet Says Journalist’s Packed-up Corvette Z06 Had Dirty Oil...”


  • avatar
    Firestorm 500

    Maybe Chevrolet needs to start using Wix oil filters, which are the best on the market.

    Instead of the $2.50 AC filters.

    Also, after machining the block, why aren’t they washing it down? I thought these engines were “hand made” to insure quality.

    • 0 avatar
      heavy handle

      The poor machining is at the oil filter, so the shavings have to make it around the engine at least once before they get filtered.

      • 0 avatar
        MBella

        This isn’t just GM. The industry is getting so focused on cutting every penny out of the production process, that quality machining is going away. That is assuming they are machining at all. Sealing surfaces are now being cast or stamped. Threads are being extruded by running the bolts into cast holes instead of being tapped. Deburring is nonexistent.

        • 0 avatar
          beastpilot

          Do you have any links or pointers to the process where you can use a bolt to just tap the threads? In all seriousness, I have a project that could really use this technology.

        • 0 avatar
          dantes_inferno

          > This isn’t just GM. The industry is getting so focused on cutting every penny out of the production process, that quality machining is going away.

          That is classic bean-counter engineering at its finest.

    • 0 avatar
      Scoutdude

      You mean Wix the company that produced filters for the Cummins found in Dodge pickups that were full of metal shaving that were then released into the engine damaging them? They did own up to it and bought a lot of engines.

  • avatar
    nels0300

    Sheesh. If I was one of these owners I’d want a new car.

    Chevy’s advice:

    “Change your oil before 500 miles to avoid “catastrophic failure”

    REALLY?

    If the oil is so contaminated that it would cause catastrophic failure in 500 miles, who is to say it didn’t cause damage at 400 miles…or 30 miles.

    If the number of affected vehicles is such a small #, as GM claims, then they should just give these people a new Corvette.

    • 0 avatar
      jrhmobile

      Exactly. Changing your oil in a car with scored bearings is only postponing the inevitable. Damage already done, it’s just a matter of time ’til the engine pays the price.

      Like, maybe to the end of the warranty period …

    • 0 avatar
      DeadWeight

      At Guangzhou Motor (GM), quality is Job #486th.

      This is their halo vehicle, and they have filter contamination from factory installed oil filters doing catastrophic damage to what appears to be a highly temperamental/delicate engine within 500 miles, to the point of connecting rod/piston failures.

      Great engineering.

      • 0 avatar
        TonyJZX

        Deadweight has it.

        This is their car, their engine, their oil, their oil filter.

        Its all on them.

        Disclosure, I drive a GM, engine and box is ok, the rest of the car? eh… what do you expect from a car with 50% China parts… Guangzhou Motors indeed

      • 0 avatar

        Seems less an engineering issue and more an assembly line one…

      • 0 avatar
        SCE to AUX

        Every modern engine with bearing clearances measured in tenths of thousandths is ‘delicate’ and ‘temperamental’ when metal chips try to pass through them.

        There is nothing wrong with the engine design; this is purely an elemental manufacturing issue. It has apparently been fixed, but GM is trying to do damage control (literally).

        These few buyers should get new Corvettes with the original cars’ VINs.

      • 0 avatar
        dantes_inferno

        > At Guangzhou Motor (GM), quality is Job #486th.

        486th is being TOO generous.

  • avatar
    Rday

    Remember this is GM…what else would you expect.

    • 0 avatar
      nels0300

      It’s their halo car and I’d expect them to at least take care of those customers, especially since it’s “less than 1% of Z06 cars”. What is that, like 7 cars?

  • avatar
    Power6

    Seesh other posters who cant read…they said it was from debris from tapping the filter threads…ie manufacturing not the oil filter…and the problem might have been avoided by the 500 mile oil change not that missing it caused the failure.

    People just dont read and say some crap they already wanted to say because Internet.

    • 0 avatar
      Firestorm 500

      As I said earlier, you always wash the block after machining. And before assembly.

      Every. Time.

      If you cut corners during building an engine, it WILL come back around and bite you.

      Chevrolet should give the owners of the blown-engine Vettes a free replacement car. Then use the buy-backs as test mules and crash testers.

      As usual, they are putting the responsibility of correcting poor assembly practice on the owners.

      The New GM. Same as the Old GM.

      • 0 avatar
        JimC2

        “As I said earlier, you always wash the block after machining. And before assembly.”

        ^^^ +1

        This is really basic stuff, people.

        If you wash your car with a dirty sponge then you’re gonna scratch the paint. If you wash your dishes in dirty dishwater then you didn’t really wash them. If you put crumpled up paper in the photocopier than it’ll jam.

        This is a bit like a fine restaurant, with a cook who didn’t wash his hands, and then believing it’s a hunkydory business solution to advise customers to take some meds after dessert because the food might or might not make a few of them sick.

        (sigh)

      • 0 avatar
        Power6

        I would agree this is very similar to some tricks Subaru has pulled. You actually hope your engine does blow at least you get a good new one rather than sweat it out hoping yours is OK…

        if this washing step is so critical and obvious why would GM miss it?

        • 0 avatar
          JimC2

          “if this washing step is so critical and obvious why would GM miss it?”

          Probably comes down to just one person screwing up… kinda like my cook washing his hands analogy. You can’t nor should you try to micromanage people for such basic stuff 100% of the time.

          Or maybe it came down to one guy, whose job it is to watch the robot that taps and chases threads, misunderstand one critical detail about how the robot is supposed to work. Not necessarily rampant incompetence but a combination of incompetence and an honest (but very serious) mistake.

          I’m just spitballing here.

          (From the customer-brand relationship, it doesn’t matter exactly where the process failure occurred.)

          • 0 avatar

            As I said below, I’m guessing this is mostly a vendor issue. I built an LS9 at GM’s performance build center in Wixom, MI before they moved it to the Corvette plant complex in Kentucky.

            The high performance LSx engines, and I’m assuming the same is true for the LT4, didn’t use a standard GM-cast block. A specialty vendor casts those blocks and they arrive at the PBC already inspected and ready to go. While some internal parts like pistons and the crank get additional inspection at the PBC during the build, the process I was part of didn’t involve any cleaning or inspecting of the block.

            I don’t think I’ve ever seen an engine with a spin-on oil filter that didn’t use a separate threaded insert. I suppose the problem could have been with the threading of the block to take that insert, but that would have been done on the transfer line along with the rest of the block’s machining, so the chance that the chips wouldn’t be chased and flushed is rare.

            Again, I think a vendor screwed up on a relatively simple part and GM didn’t catch it during assembly. Unless the story is complete BS, I am a bit impressed that they were able to actually locate the source of the problem – though there are a limited number of steel internal parts to that engine, so the checklist wasn’t that long.

            The total number of customers affected is small and I’m guessing that GM will be accommodating the owners one way or another.

            There have been all sorts of unofficial recalls and out of warranty repairs. GM will do likewise.

            If we don’t hear Z06 owners complaining, that’s probably what’s happening.

          • 0 avatar
            SP

            I think GM’s explanation is false, or the proposed fix is false. Here’s why.

            If there is debris from tapping threads for the oil filter somewhere in the oiling system, then it will either get caught in the filter, or it will get caught somewhere in the engine (say in the oiling hole for a rod bearing). (If the debris is too small to get caught in one of those places, then it’s too small to worry about.)

            If the debris gets caught in the filter, then an oil & filter change will remove it … but it won’t matter because it was already caught in the filter and rendered harmless. So that means changing the oil is just a placebo.

            If the debris gets caught in the engine, then changing the oil and filter will not remove it, because it’s not in the filter, and it’s not in the oil pan. So that means changing the oil is just a placebo.

            Either way, it sounds false to me.

      • 0 avatar
        Pch101

        Taking your argument to its logical conclusion, no car should ever require an oil change because the only engine that can fail with bad oil is a defective one.

        If the OEM says that the oil needs to be changed following an initial break-in period (which is not exactly unusual), then change it. If that offends your sensibilities for whatever reason, then don’t buy the car.

      • 0 avatar
        VenomV12

        Agreed, at what point do you stop making excuses for this company? This is a $90,000 high performance exotic car, this kind of stuff should not be happening.

      • 0 avatar
        dantes_inferno

        >The New GM. Same as the Old GM.

        No one sweats the recalls like GM.

  • avatar
    seth1065

    What did Chevy do so this will not happen on the later made cars since they said it is only on the early ones, perhaps Chevy should pick up the vetts after 400 miles and have the oil changed and cars returned to the customer.

    • 0 avatar
      DenverMike

      The later production ZO6s have less miles or still sitting in a showroom. And less likely to be raced around a track.

      GM needs to buy back all ZO6s in that production run, but resell them with the notice the engine has be been rebuilt or replaced, plus a transferable 200,000 (total) mile warranty extension on the engine.

      • 0 avatar
        Power6

        The problem with a solution like this, is that to do the right thing would be crushingly expensive and they will do anything to avoid it. Subaru did this with bad runs of rod bearings. The internets figured out the 3 months they made bad engines but Subaru would only replace if the engine blows, not if it came from the proven bad batch…they just wont do it, would cost too much.

        • 0 avatar
          DenverMike

          The big difference is these are high dollar halo-cars, not disposable daily drivers that rack up the miles quick. A bad engine build will show up immediately on the daily grind.

          GM needs to fix this the right way, partly because it is halo car. Or what does it say about the rest of their turkeys and how they’ll handle problems on those.

      • 0 avatar
        dantes_inferno

        > The later production ZO6s have less miles or still sitting in a showroom. And less likely to be raced around a track.

        Which means the metal shavings should be nice and fresh for the next new pigeon… uhh, I mean owner…

  • avatar
    RHD

    Do Corvettes have magnetic drain plugs?
    That should be an industry standard.

    • 0 avatar
      Firestorm 500

      Aluminum engine components. Non-magnetic.

      • 0 avatar
        SCE to AUX

        Um, there are plenty of ferrous wear items in an engine – oil pump, cylinder sleeves, lifters, cams, crankshaft, rocker arms, pushrods.

        I’m sure it has a magnetic drain plug. But that won’t prevent damage from the stuff which already passed through the engine, or remains stuck inside a lifter.

  • avatar
    LS1Fan

    When GM screws up a minority of Corvettes :

    “OMG GM SUXXXX AMERICAN KARS CRAAAP”

    When a German company screws up an IMS bearing which is installed on 98% of its desirable products over a course of years and can suddenly blow an engine without warning :

    “EES PORSCHE.SUPERIOR GERMAN BUILD! DAS ESTIMATE EES SUPPOSED TO HAVE ZE EXTRA ZEROS ON LEFT SIDE OF ZE DECIMAL “

    • 0 avatar
      jrhmobile

      Word.

    • 0 avatar
      chuckrs

      Does Chevy really want to follow Porsche’s lead in handling the fallout? It took Porsche three tries to spec an IMS bearing that seems to work OK. Also, Porsche never really fully disclosed the nature of the problem and the percentages affected, so Chevy has already been more forthcoming.

      If this affects only 1% of the cars already delivered, why wouldn’t they run the cost numbers on extending the warranty on the engine to 100k miles? A quick check on production numbers suggests fewer than 100 cars are affected. They might replace a few engines where damage was caused by pilot error, but it would reassure many who drive more sedately. I know someone who has an early one and like a lot of Porsche and Corvette drivers, he’s older and doesn’t track it. If Chevy is convinced that you can circulate metal shavings for 500 miles and then still get a full engine life then they should put their money where their corporate mouth is.

      ps – I am an older owner of an older Cayman S with the IMS engine. 50kmiles and counting. These cars have the third bearing tried and it seems to work.

      • 0 avatar
        TonyJZX

        The difference is Porsche is up there with Apple as being one of the Top 5 most valuable brands in the world.

        If you’re on the pedestal with a rabbid and completely sycophantic audience then yeah, you can get away with murder or at least ritual suicide (of your employees).

        Guangzhou Motor (GM)? not so much…

        You do remember 2009 right? Did Porsche ask for german taxpayers money to the tune of several billion?

        You’re gonna collect hate until the end of time.

        • 0 avatar
          LS1Fan

          Interesting. So Porsche never had financial difficulties in all their years of operation.

          I ought to get new history books then.

          In any event, GM gets a lot more hate then they deserve. For all the metric tons of Hatorade poured on the F-Body and C5 Corvette for ‘poor interior quality’, at least the damn subframe will still be in one piece……AMIRITE, BMW E46 owners?

          • 0 avatar
            chuckrs

            They nearly went broke in 1991. From 1992 to 1994, Porsche “took in the wash”, hand building Mercedes 500Es and E500s. These had mods to the suspension and body plus an engine that gives them creditable performance by today’s standards. I don’t know if there was government cheese involved…..

          • 0 avatar
            dantes_inferno

            >AMIRITE, BMW E46 owners?

            That’s right you aficionados of automobiles from the new Bailout Motors.

      • 0 avatar
        DenverMike

        When only geezer driven on the 3rd Sunday of the month to church and back, it could take years for the damaged engines to grenade. One great grandson, out of warranty joyride in 2021 and Pop!

    • 0 avatar
      Maintainer

      @LS1Fan

      No joke! Over the last few months I’ve seen so many comments and a few articles brushing off the IMS issue as “it’s not really THAT bad” it’s not even close to funny.

      • 0 avatar
        TonyJZX

        IMS is serious. And how Porsche brushed it under the table is scandalous.

        Here’s the thing though… it only affected the rich 1% of 911 and Boxster owners. And then not all of them.

        Do you have any sympathy for this well off individuals? I dont. They can take the hit, believe me. And the reality is, the people who were directly affected by this are less upset than the internet and they are already two or three Porsches removed from the 996 era.

        Here’s also another disconnect. GM takes a hit as they were the poster child for the bailouts. I see it as unfair. Why didnt Chrysler take a hit?

        The world is unfair. Harden up. And Porsche has had financial difficulties. But it is childish to bring that up. Its like slagging off Apple for that time they took $110 million from Microsoft. No one cares. It is ancient history. Look at them now. People have a short memory when their current state is as golden as Apple or Porsche’s capitalisation.

        Again, GM… not so much…

        • 0 avatar
          LS1Fan

          History is never childish. It may, however, be very inconvenient if ones point is that American vehicles are somehow abnormally and perpetually inferior.

          Yes, Chevy screwed the pooch. But they’re acknowledging the problem and are taking steps to fix it.

          Meanwhile, German car fans have to either CAT-scan their prospective used car purchase or call the bank for a home equity loan when their drivers side window regulator goes out,all the while saying ‘Murrica can’t build a decent car. Forget that noise.

          My own example of American performance may be unrefined, but I don’t need to ask my fiancee to pick up a spare Fuel pump on her way home from work.

          • 0 avatar
            DenverMike

            Taking steps to fix the problem? GM?? You mean Baby steps???

            Chevy does get a passing grade for reliability, and excellent reliability compared to German performance, however, acknowledging the problem plus telling owners to change their oil falls a little short.

          • 0 avatar
            dantes_inferno

            >My own example of American performance may be unrefined, but I don’t need to ask my fiancee to pick up a spare Fuel pump on her way home from work.

            It’s nice to hear from someone who is determined to get his money’s worth of his tax dollars invested in GM. Every penny.

            Look, here’s the bottom line. The problem with GM doesn’t lie in their manufacturing or engineering. The problem lies with the same old archaic GM management/beancounting structure and decision making which have had a ripple effect on their manufacturing and engineering departments for decades.

            All of the reorganizations which took place within GM amount to nothing more than mere window dressing. The same old crumbling infrastructure is still in place – but with a new exterior.

      • 0 avatar
        CJinSD

        I certainly haven’t made light of the IMS issue. Porsche has no integrity. Is Chevrolet trying to emulate them? This probably isn’t the secret to their success.

    • 0 avatar
      APaGttH

      This.

      How are those plastic/nylon manifolds doing on those Porsche engines…

      Or fuel pumps on BMWs…

      Or Audi A8s with the V10 engine that burst into flames on command…

      Or Nissan GT-R with self-destructing transmissions…

      Or…

  • avatar
    dwford

    I thought we were decades past the old Dad’s tale of having to change your new car oil at 500 miles. Way to go retro, GM.

  • avatar
    carguy67

    Changing the oil at 500 miles won’t do much good if some of the shavings got embedded in the bearings at 499 miles.

  • avatar
    Firestorm 500

    The older you get, the wiser Old Dad seems to be.

  • avatar

    This sounds to me like a problem at the vendor who supplies the threaded fitting for the oil filter. The engine has an aluminum block so it likely has a threaded steel insert for the oil filter. The female threaded plate on an oil filter is made of steel, and screwing steel onto aluminum is asking for galvanic corrosion, leading to filters that are corroded on.

    If they are using a separate part, it makes no manufacturing sense to thread the part after it’s been installed onto the block.

    My guess is that the vendor didn’t properly “chase” the threads after machining the insert.

    • 0 avatar
      John

      It ain’t that hard to check the gol-dang threads before screwing the part into the engine, ya know? My penniless going-to-college daughter’s 2002 Honda Civic LE has an aluminum block, with a threaded steel insert for the oil filter, and Honda managed to stick the part in clean – we changed the valve cover gasket last weekend – with over 180,000 miles on the clock, everything was clean and shiny. No excuse for this in Chevy’s ultra-high-performance engine.

    • 0 avatar
      wmba

      “Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact, in the presence of an electrolyte.”

      What electrolyte are you proposing could cause galvanic corrosion in this case? Millions upon millions of aluminum engines have iron cylinder liners, and even steel strengthening inserts cast into the aluminum.

      This is not a case of steel/aluminum body panels in contact with acid rain as an electrolyte. The insert would have traces of cutting oil or whatever was used to wash it after machining on it. No enabling electrolyte.

      I’ve never seen this situation you hypothesize.

  • avatar
    John

    No – not “In other words, change your oil”. In other words – Chevy – get the gol-dang metal shavings out of the gol-dang engine before you button it up and ship it to the customer – like any redneck, elementary school education shade-tree mechanic would tell you to do. Blaming damage from production line metal shavings left in the engine on customers not changing their oil is the ultimate in “blame the victim” fraud, and shows utter contempt for people who buy these very expensive automobiles.

  • avatar
    runs_on_h8raide

    Hey…what’s the TrueCar price on one of these bad-batch new Zblow6’s?

    Sad that the 2nd owners of those “200 mile still in wrapper” Zblow6s will blow their motors 30 years from now after buying them at a Barret-Jackson auction. Hey…but #s matching, man!!

  • avatar
    dal20402

    GM: good design being let down by slipshod execution since before any of us were born.

    If my G8’s interior had had materials even roughly appropriate for the price point screwed together even somewhat acceptably, I might still have it.

  • avatar
    Ion

    One of the things I’ve been wondering here is why GM shifted back to spin-on filters instead of canisters. I noticed it on the new CTS so it’s not a performance issue. Furthermore other makes use cartridge filters in high performance engines without any issues.

    • 0 avatar
      SCE to AUX

      It’s not a filter issue; spin-on filters are just fine.

      This was a manufacturing error which happened to occur at the filter site. It could just as easily have happened anywhere else on the engine.

      • 0 avatar
        Ion

        It is indirectly a filter issue. Were GM still using their “environmently friendly” canister filters there would be no spindle and thus no spindle shavings to contaminate the oil. Though to be fair the early Saturn V6 canister housings did have a tendency to become unscrewed from the block.

  • avatar

    GM messed up, and should stand behind it. So should Porsche. BMW, to its credit, over the years, ate a lot of engines and does more buybacks than the others.

    Perception is key here. The cars we care about are limited in production, market but not in interest. If the latest and greatest Vette or Cayman is tossing big parts, the internets all “know”, mostly repeating the five posts from smart folks who have been bitten. I don’t have a Vette, nor am I likely to attain my fantasy Vette collection with my kid’s college bills, but I “care” like any car guy….

    For years, the only folks who knew a car “had a problem” were the bean counters in Warranty and the engineers who got their mememos, and a smattering of Service Managers who had the same unhappy customers for the same reasons. Now, you don’t even have to have the car or know anything to slag it.

    Also, I’ve learned trolling BMW boards that a failure of a part is analyzed in a way the typical CamCord owner won’t notice. (Pages and pages of how the expansion tank goes, for example) I was so used to detailed posts from BMW when I started reading about the MDX, the level of discussion went from borderline engineering school to “whats that noise ? The dealer says”.

    Rest assured, the typical passerby sees the new Z06, and says WOW, not “whatta POS”. Likewise every Porsche, IMS or not…. Porsche said “eat it” with the IMS because they knew they could.

    On the other side, if a percentage of engines will fail, but not all, or even most, then, you don’t want to replace good engines and piss off thousands of folks who really don’t have a problem, not to mention the havoc dealer monkeys can cause upsetting a correctly built car with flat rate mentality.

  • avatar
    65corvair

    I’ve opened up filters a couple of times at my new cars first oil change. I’ve never found anything in them. I couldn’t even tell which way the oil flows through them, both sides of the filter paper looked the same.

  • avatar
    05lgt

    Mah Corvette blew it’s engine due to dirty oil; #Thanks Santorum.

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