By on April 13, 2018

 

mazda skyactiv

Brian writes:

Hi Sajeev,

You are my go-to guy for in-depth automotive knowledge. (Wow! Honored. – SM)

My brother has been having a heck of a time with his 2012 Mazda3 Skyactiv. It’s got about 70k miles on it, and in the past 2 years it’s been in and out of the shop. It started with high engine oil consumption (more than a quart per 3k miles, and going up to this day). Then the ignition coils needed to be replaced. Then the MAF and oxygen sensors needed to be replaced. Right after those were fixed, he had to take it back to the shop because there is now a misfire in one of the cylinders.

What’s going on here? My only guesses are worn piston rings causing engine oil to run into the combustion chamber (then down the exhaust and ruining the O2 sensor), or malfunctioning PCV, a broken EGR system, intake valves with a lot of carbon deposits, or simply “bad luck” with this car.

Hope you are able to shed some light on this mystery. Thanks!

Sajeev answers:

As we all know, Skyactiv engines improve fuel economy without the usual side effect of a wheezy, wimpy powerband. But you can’t have your cake and eat it too: low tension piston rings ensure this truth. But is this really a problem?

I’ve postulated that oil burning is likely a net positive in modern engines and — unless a Dieselgate-worthy scandal comes upon us — this will continue. So tell your brother to not fear the oil consumption issue, unless the rate doubles in a fraction of the current time/mileage interval.

The other issues are worrisome, but less about the car and more about the diagnoses. What engine codes were generated to merit replacing all those bits? Armchair quarterbacking is a dangerous profession, but it seems like this direct-injected motor got a lot of parts thrown at the problem. Parts that either went bad because the motor wasn’t de-carboned, or they weren’t bad to start.

I’ve been spilling digital ink about de-carbonizing Direct-Injected engines for years (at least 2012) and that’s likely what your brother’s Mazda needs. Perhaps the traditional chemicals/walnut shell/whatever Mazda recommends as a treatment won’t cut it now, and perhaps the intake/EGR system needs a good physical cleaning on the workbench?

What say you, Best and Brightest?

[Image: Mazda]

Send your queries to [email protected]com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice. 

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81 Comments on “Piston Slap: Misfiring on Mazda 3 Skyactiv’s Diagnosis?...”


  • avatar
    rpn453

    I think misfire and downstream problems are more likely to be related to valve issues than piston rings. Being a direct injection engine, I’d use nothing but top tier fuel to keep those clean.

    Many possibilities. It does sound like a lot of parts are being thrown at it. I’d start with a compression test and spark plugs, following a forum search for similar issues.

    The oil consumption itself wouldn’t bother me.

    • 0 avatar
      Kenn

      “Being a direct injection engine, I’d use nothing but top tier fuel to keep those clean.”

      Being a direct injection engine, gasoline bypasses the intake valves – that’s why the valve deposit problem arises. Only port injection allows fuel to clean intake valves. I’m curious how well Toyota’s newest combined port- and direct-injection system will keep intake valves clean.

      • 0 avatar
        rpn453

        It might not be enough to clean up dirty valves without port injection, but I think it does reduce the deposit formation.

        Just a general comment on DI engines.

    • 0 avatar
      jeremyb

      As a Mazda dealer service manager on his second Skyactive car, I can tell you these cars are extremely reliable. I have been working with Mazda vehicles well before the Skyactive series of engines debuted. I have never seen one of these cars with oil consumption or a misfire. I see these cars on a daily basis and can tell you that the average customer does the very minimum to maintain these cars. I suspect this car has been severely neglected to be burning oil as stated.

      I am curious if the plugs have been replaced (not due yet at 70k). Do you if the parts replaced have been OEM?

  • avatar
    gtem

    I was always kind of leery of how high Mazda went with the compression ratios on these SkyActiv motors. Not terribly surprising that an early-year version would see some teething issues as the miles piled on. One hopes that they have it sorted now, 5+ years on.

    • 0 avatar
      gtem

      One thought is that high compression ratio was causing extra pressure to build up in the crankcase and the PCV system was just blowing a ton of oil out, which on a DI vehicle without adequate intake valve wash-down will surely lead to some coking/build up on the intake valves. Were the MAF and coils actually found to be faulty, or was that dealership techs playing a game of “follow the factory flow chart and load up the parts cannon” to try and resolve a lumpy idle and misfiring due to poor compression due to valve build-up?

  • avatar
    VW4motion

    1. Sell that Mazda now.
    2. Don’t buy another Mazda.
    3. Buy a Corolla. Maybe it’s boring. But it won’t misfire even at 200,000 miles.

    • 0 avatar
      gtem

      I will say I’m in the process of helping a friend sell his ’09 Mazda3 2.3S (156k miles). It’s not had any engine/transmission problems and has served him well aside from an A/C compressor that was replaced once (with questionable parts) and the replacement is now making noise. Suspension feels a bit past it, no doubt needs some struts and definitely some swaybar links. None of that is something I’d really hold against the car. What I will say is a major problem is that this car has a classic case of Mazda fender rot. It’s a 2009 and the passenger rear quarter panel lip is just about fully rotted through. Not very visible yet, but one more winter and it’d be perforated.

      • 0 avatar
        VW4motion

        I thought Mazda fixed those rusting issues. We see not. Side note, last winter I saw many new Mazda on flat bed trucks, and even in my neighborhood two Mazda 3’s had starting issues on cold mornings. One guy did tell me his battery was bad at 9 months. But after the battery was replaced I saw him jump starting it the next month. We moved and never asked what became of the issue.

        • 0 avatar
          gtem

          Also worth mentioning the ’09 Was the last year of the 1st gen before they went to the “smiley” look and perhaps(?) implemented some changes to improve rust-proofing. Also this 2.3L is just a classic Mazda/Duratec port injected chain driven unit, no DI worries at least.

          It’s certainly a more rewarding car to drive and has a better looking interior than the grey/beige cost cut hell that is a 10th gen Corolla interior. A different friend likewise sold an ’09 Corolla of that generation earlier this year (to buy an ’02 4Runner no less). I will say where the Corolla shines in relation to the Mazda is maintaining a very smooth and like-new ride and a interior with no rattles and minimal wear even when subjected to horrible roads and general neglect. That’s in spite of the interior materials feeling much cheaper than say a 1990s Corolla (aside from nice velour which 10th gen Corollas still got). The Corolla did require a starter at less than 100k miles IIRC, the only non-maintenance thing I can think of on that car.

          • 0 avatar
            slavuta

            gtem,

            I had Protege, my niece had 1st gen ‘3, I have 2 2nd gen ‘3s. I can tell you all about rust. In fact, I wrote many times about it.

        • 0 avatar
          JohnTaurus

          Yes, everyone knows that when a car maker fixes an issue, it automatically becomes retroactive and fixes previous models produced half a decade or more earlier. Excellent deduction. Just like that Corollas never have issues in 200k, another stunning development that clashes hard with reality.

    • 0 avatar
      slavuta

      Corolla will not misfire. It will eat your oil like there is no tomorrow

      • 0 avatar
        gtem

        A whole slew of car makers suffered through a transition to low viscosity synthetics coupled with new low-tension oil rings in the 2010-ish range, everyone from Toyota to Volvo to Subaru, probably many others. My 2012 Civic owned from 11k miles until 53k typically used half a quart between 7500 mile intervals, my 22 year old 4Runner with 147k uses almost none even on long summer road trips that take us through WV’s passes. Our old ’98 MPV with the low compression JE 3.0L V6 used about half a quart to a quart by 160k miles.

        • 0 avatar
          slavuta

          Look, your 4Runner with big v6 should never use more oil than small 4cyl. How many revs per min big rig does vs revvy Mazda engine. (Remember, mazda engines rpm-happy). So, there is little wear on all 6 cyl/pistons.
          By 100K miles 4cyl engine might made 50M more frictions. This is why big engine should last way longer

          • 0 avatar
            gtem

            You’re not wrong, but I’ll point to my Lima-engined 2.3L Rangers that don’t seem to use much oil at all either, even past the 2-decades old mark. I think it is indeed largely a function of this recent switch to very low viscosity synthetics coupled simultaneously to a switch to the new low tension oil rings. Some engines just seem more or less predisposed to it. Plenty of Chevy 350 small blocks are known to start using oil by the 100-150k mark, despite their low revving nature. So there are some generic drivers of these issues (low revving/understressed vs high revving, thinner oils), but also some engines that just seem to hold up better with mileage, some worse. Isuzu had a serious issue with their DOHC 3.5L in the Trooper for example,the problem there apparently was the oil ring on the piston cooking itself to the piston.

        • 0 avatar

          My ’14 Fusion with 2.0L Ecoboost does not consume oil at all. It has about 50K on odometer and I replace oil every 7500 miles – never added oil between changes so far. It is DI engine BTW.

          • 0 avatar
            dantes_inferno

            >My ’14 Fusion with 2.0L Ecoboost does not consume oil at all. It has about 50K on odometer and I replace oil every 7500 miles – never added oil between changes so far. It is DI engine BTW.

            Living on borrowed time…

      • 0 avatar
        dantes_inferno

        >Corolla will not misfire. It will eat your oil like there is no tomorrow

        …as well as your soul…

    • 0 avatar
      JohnTaurus

      LMAO

    • 0 avatar
      28-Cars-Later

      So to sum up:

      1. Sell your Mazda and don’t buy another Mazda.
      2. ???
      3. Profit.

    • 0 avatar
      ernest

      Or a Rav4.

  • avatar
    tylanner

    Pull the offending spark plug…is it fouled with oil?
    A bad PCV will make a mess.

  • avatar
    redapple

    RE: Problems besides the Oil Consumption.

    USed car?

    Did anyone wash the engine? Power wash? Spraying water into the engine compartment and onto the engine and environs causes ALL KINDS OF PROBLEMS.

    Never do this.

    Should never have these number of problems at 70K miles.

    • 0 avatar
      JohnTaurus

      I’ve washed the engine in my 24 year old car several times (along with many others as I sometimes detail cars). No issues. If water hurts your modern engine, it has an issue that needs to be addressed.

  • avatar
    MrGrieves

    First-generation DI engines tend to have valve coking issues, which might be what’s going on here. I’ve got no experience with Mazdas, but have with BMW and VW DI engines. From what I’ve experienced firsthand, fuel additives, treatments, etc., don’t really help the problem. Two things will, though: The old “Italian tune up” every so often, and the Walnut Shell blast (or some other physical removal of deposits in the intake.)

    I recommended the Walnut Shell blast to a friend who was having issues with his BMW 335i rough idle / misfire / power loss. It worked pretty well.

  • avatar
    RSF

    A Mazda with engine troubles. Imagine that..

    • 0 avatar
      slavuta

      In my world so far, Mazda engine was solid. My Protege had 195K when I sold it and engine was its strongest point. I have now 82K and 120K on ’10 and ’11 Mazda3 and engines are fine. Doesn’t even burn any oil. My 120K Toyota burns like hell.

    • 0 avatar
      mike978

      RSF being disingenuous. Imagine that ….
      The Mazda hate is strong with that one.

      • 0 avatar
        ToddAtlasF1

        I run an independent shop. Mazdas as new as 2012 with engine troubles are grossly over-represented in my service bays. They might not fail at the rate Subaru and Ford engines do, but they might well fail at a higher rate too, when you consider how scarce Mazdas are to begin with.

        • 0 avatar
          slavuta

          ToddAtlasF1,
          I really appreciate your “eye opener”. I also run independent shop [sort of] where in the last 20 years I had 7 Mazda cars and not one had ANY engine issues.

    • 0 avatar
      sutherland555

      To my knowledge, engine problems aren’t a common Mazda problem. Maybe the earlier Ford derived engines were troublesome? But the Skyactiv engines have been very reliable. From my personal experience, my 2013 Mazda3 2.0 Skyactiv w/ 90k km has been rock solid.

  • avatar
    ajla

    “I’ve postulated that oil burning is likely a net positive in modern engines”

    I disagree with you on that, because I’ve seen this happen more than once.

    -Take modern, long OCIs.
    -Add in an engine that consumes a quart of oil every 3k (or so).
    -Give it an elderly/busy owner that knows zero about vehicles and goes on lots of short in-town trips.

    And the result is an engine that pops off around 100k. At which point all those fuel savings are gone (and likely much more) unless you spent money on an extended warranty or the manufacturer cuts you a big break on repairs.

    • 0 avatar
      gtem

      I think the biggest shift is for traditional domestic buyers that are used to something simple and crude like a 3800 where a once-in-a-blue-moon Jiffy Lube visit gets you by just fine. All of a sudden their Impala or Malibu needs Dexos approved synthetic to keep the long OHC timing chain happy and GM specified a 10k interval…

      • 0 avatar
        PrincipalDan

        I was behind a not all that old Grand Marquis that was burning oil fiercely a few days ago. I thought: Man that sucker must have been abused cause after the initial teething problems those 4.6 were another engine that made you think preventative maintenance was a waste of money.”

        I also think that manufacturers are in some cases spec-ing huge oil sumps to guard against some of that modern oil burning. My 3.5 V6 takes about 7 quarts when an old 5 ltr V8 would take 5 quarts.

        I agree with Ajla about the short trip thing too. Now my wife’s commute doesn’t leave the city limits while mine is 60 miles round trip. I push her to let us take her vehicle for long out of town trips AND I’m dropping a fuel system cleaner (for DI engines) in the tank after every oil change. Not many sources of “TOP TIER” gasoline in Gallup NM.

        • 0 avatar
          gtem

          “I also think that manufacturers are in some cases spec-ing huge oil sumps to guard against some of that modern oil burning. My 3.5 V6 takes about 7 quarts when an old 5 ltr V8 would take 5 quarts.”

          The big sumps are along with synthetic oil a large part of extending oil intervals safely IMO. I’m actually always a bit taken aback at how little oil there is in a 350 sump. Doesn’t leave too much room for burning/leaking.

          • 0 avatar
            PrincipalDan

            My old Olds 307 was 5 quarts (of course) and did get to that “One quart every 3000 miles” point after about 120,000 miles. Fortunately the “oil” light would come on without fail. A quart of Marvel Mystery Oil replacing one of the quarts of regular 10w30 cured the issue.

            It takes me aback a little that part of the reason oil changes cost so dang much is that there’s so much oil to put in there to start with.

        • 0 avatar
          dukeisduke

          3.5 – is that the Toyota 2GR-FE? In the Sienna, it takes 6.4 quarts with filter. I hate the cartridge-type oil filter, as it’s a pain to change. There are spin-on adapters out there, but they’re insanely priced (around $250 is what I’ve seen).

        • 0 avatar
          bumpy ii

          “I was behind a not all that old Grand Marquis that was burning oil fiercely a few days ago.”

          Naah, that’s just Ford Smoke.

  • avatar
    slavuta

    Ah, don’t call this one Skyactiv. May be deluded Skyactiv at best.

    This question doesn’t say anything about how often oil was changed and what oil was used. Hence noting to talk about. My ’10 Mazda3 2L with no skyactiv burns no oil @ 120K. I change every 5K miles with plain 5w20 stuff. No issues.
    Also, nothing about gas being used. TOP tear proven its cleaning abilities. Gotta put some of that periodically.

    • 0 avatar
      WheelMcCoy

      “Ah, don’t call this one Skyactiv. May be deluded Skyactiv at best.”

      That’s what I recall too… first generation.. or perhaps version .5… there was no room in the engine bay for the real manifold to cool exhaust gases. Anyway, it was also Mazda’s first implementation of DI, so I agree with those who suspect it’s carbon build-up on the valves. With DI, gasoline can’t wash them clean.

      That said, we are missing information on engine codes, general maintenance, and driving habits.

  • avatar
    incautious

    I’m not saying that this wasn’t maintained, but the coil problems most likely caused my worn plugs. 100K plugs are a myth. So are 10k mile oil changes. I to own a DI auto(Audi) and although there are several DIY decarbon products, I still use the tried and true Italian tune up method which has worked well. Get on the freeway and floor it get up close to redline.
    back of and do it again and again. This usually works in getting rid of all that pesky carbon.

    • 0 avatar
      WheelMcCoy

      “So are 10k mile oil changes.”

      10K mile oil changes (or once a year) is doable, provided you use synthetic oil and a good oil filter designed for the distance. I’ve done this and submitted oil samples to Blackstone labs on two separate changes. The engine is fine and the oil sample still had active detergents.

      • 0 avatar
        FreedMike

        My Jetta has a 10K manufacturer-required oil change interval with synthetic oil.

        • 0 avatar
          dantes_inferno

          > My Jetta has a 10K manufacturer-required oil change interval with synthetic oil.

          Your engine will be much happier with 7500 to 8000 mile change intervals. I wouldn’t trust the 10K service interval any further than I can throw a vehicle – especially with Castrol Edge as the factory fill.

          As far as spark plugs, I woudn’t go beyond 75K between spark plug changes.

      • 0 avatar
        ajla

        10k oil *changes* might be possible. Although I personally follow the manufacturer’s “severe-duty” schedule on my vehicles.

        10k oil *ignoring* is a myth.

    • 0 avatar
      slavuta

      Where do you guys get these 100K spark plugs things? here is the manual https://www.mymazda.com/MusaWeb/pdf/manuals/2012_Mazda3_OM.pdf
      And it clearly says 75K and 60K based on engine you have.And there is nothing about 10K oil changes either.

      • 0 avatar
        WheelMcCoy

        “And there is nothing about 10K oil changes either.”

        Don’t know about the spark plugs, but you are correct regarding 10k oil changes not specified in the OM. I just mentioned it as a feature of synthetic oil and have been using it in my 2010 Mazda3 just so I can do the job once a year. I also like to flirt with the redline, so I figure synthetic oil plus a high capacity / high surface area oil filter is the way to go.

        BTW, Toyota has switched to synthetic oil and 10k mile changes. Friends who drive them are confused when they bring their car in for service (ie: a 5k mile tire rotation) and the dealer won’t change the oil.

        • 0 avatar
          slavuta

          WheelMcCoy,

          I can tell you right now that I totally disagree with you. Look at the manual again. It doesn’t say there that oil must be synthetic. What it says, if you drive regularly, change 7.5K. But if conditions fit “hard driving” definition (defined in manual), then you use schedule 2 – 5K miles. This is the biggest fallacy of “damn specialists”. The manufacturer tested these cars and designed this service manual for owners to follow.

          When it comes to Toyota, their 10K recommendation is very tricky. Here how it goes.

          5000 miles

          Additional Maintenance Items for Special Operating Conditions

          Replace engine oil and oil filter
          .Driving on dirt roads or dusty roads
          .Driving while towing, using a car-top carrier, or heavy vehicle loading
          .Repeated trips of less than five miles in temperatures below 32°F / 0°C
          .Extensive idling and/or low speed driving for a long distance such as police, taxi or door-to-door delivery use

          NOTE:
          Your vehicle is certified with Genuine Toyota 0W20 motor oil. For
          VEHICLES CERTIFIED FOR 0W20 motor oil, the oil change interval is 10,000 miles or 12 months IF 0W20 MOTOR OIL IS BEING USED. If 0W20 is not available, 5W20 mineral oil may be used. However, it must be replaced at A 5,000 miles or 6 month INTERVAL with 0W20 motor oil.

          In other words, only if you drive mostly on highway and not standing in traffic, and if you use Genuine Toyota 0W20 motor oil, which is of course synthetic, only then you can go 10K. Plus, even if you drove only 8K in a year, then Toyota recommends still go and change it.

          Otherwise, just use regular 5w20 oil. change it every 5K and everything will be OK.

          I would rather have a clean oil 2 times in my car than 1 time in one year. See, many people don’t know how to read the manual and conclude that X is only thing. while manual clearly says that X is when Y. Otherwise – Z.

          • 0 avatar
            WheelMcCoy

            “I can tell you right now that I totally disagree with you. Look at the manual again”

            Look at my comment again. :) I was agreeing with you… the manual recommends 5W-20 regular oil. Synthetic is not needed.

            I use 0W-20 synthetic oil because I understand it’s really a better oil in my use case, and I have Blackstone lab results to back it up.

        • 0 avatar
          slavuta

          Sorry. I may didn’t read this right. Too much to do. I any case. I buy pep boys deals. And just change oil every 5K as manual suggests.

    • 0 avatar
      rpn453

      One would hope the plugs were checked and/or replaced with the coils.

      I disagree on your statements regarding maintenance intervals though. Under the right driving conditions, 10k miles is no problem even on modern conventional oils. And iridium plugs can easily do 100k miles in certain engines.

  • avatar
    pwrwrench

    I thought the carbon in the intake ports was solved 25 years ago with the changes in gasoline (more/better dispersants). Apparently it’s back with the increased oil change intervals, which many people go way beyond, and the changes to increase fuel economy and HP.
    I tend to agree with others that the coil, MAF sensor, and O2 sensor replacements are throwing parts at the problem hoping it will go away.
    20 years ago 1/2 Qt of oil consumption in 3,000 miles was considered normal.
    Now no one wants to even think about opening the hood/bonnet. If it is necessary to add oil between changes the world has come to an end.
    This Mazda 3 may have leaking valve stem seals. I agree with the idea of a compression/leak down test.

    • 0 avatar
      gtem

      “I thought the carbon in the intake ports was solved 25 years ago with the changes in gasoline (more/better dispersants). Apparently it’s back with the increased oil change intervals, which many people go way beyond, and the changes to increase fuel economy and HP.”

      It has everything to do with missing “washdown” cycle traditionally taken for granted with port-injected gasoline engines. Atomized air and fuel are sucked down the intake runner, past the intake valves. with DI you lose this. Some, like Toyota and now VW (after getting burned) have reintroduced port injectors in addition to the DI setups to help with cold start emissions and smoother running at least nominally. But they gain back the wash cycle. Other manufacturers with pure-DI engines have learned to alter the cam timing profiles (using VVT systems that most everyone has nowadays) to allow the fuel/air mixture to come into more contact with opened intake valves.

      Nothing inherently to do with oil change intervals. But IMO it IS related to engines routing crankcase fumes (vaporized motor oil) back into the intake manifold to be burned up. This has been the case for decades but again we had that washdown cycle to mitigate effects. This is a big cause for varnish and coking on the back sides of intake valves on DI motors IMO.

      • 0 avatar
        dantes_inferno

        >This is a big cause for varnish and coking on the back sides of intake valves on DI motors IMO.

        Concur. And since DI is a physical mechanical design, no amount of JEDI mind tricks will completely eliminate the carbon from the intake valves short of a proper cleaning (walnut blast, etc.). A catch can or Italian tune-up may slow down the accumulation of carbon, but those methods only delay the inevitable.

  • avatar
    gasser

    Do the cheap stuff first. Change plugs, plug wires and PCV valve. Then run the snot out of it on the highway.
    If the problem persists, either decide to ignore the problem or trade the car. As I recall, the walnut valve treatment isn’t cheap, and still might not solve the problem.

  • avatar
    KrisZ

    “I’ve postulated that oil burning is likely a net positive in modern engines…”

    One can postulate nonsense all day long and be nowhere near close to the truth.

    Burning excessive amounts of oil is never a good thing in a four stroke engine. Never was and never will. It leads to too many side effects that will eventually lead to problems. These problems don’t usually surface until well past 100k mile mark, so for a lot of people it may seem like an acceptable situation.

    Many new engines do burn oil, but this should not be taken as a sign that it is normal, rather a sign of poor engineering. And if this site wants to live up to its name, these things should be pointed out, not postulated as normal.

  • avatar
    incautious

    10,000 oil changes is doable but I would would never in a turbo DI motor, and I use Castrol professional at 10$ qt. same as Audi. Ask the Gm owners how that 10K interval worked out. Had to recall them to shorten the interval reminder. Or the Hemi ram owners with wiped out tappets and camshafts, despite the prof of maintenance by the book. Yes I’ve owned a distribution business and did 10K intervals in all the vans with old rotella high ZPPD, so I know 10k IS possible. so caveat emperor.

  • avatar
    nlinesk8s

    Mini Coopers had all kinds of misfire problems with their 2nd gen DI engines, so it’s a maintenance item every 30-40k. They also claimed 14k oil changes, but considering the engines use 1 qt/1000 miles, I think you’re really just changing the filter.

    BMW E46 6-cyl used two 5qt containers of oil (synthetic) for oil changes. I did 7500 mile changes, as I was doing my own, though I’m sure I could’ve done 10k instead.

    I’ve a 2017 Mazda 3. If the earlier cars have the same tiny filter, I can see why you’d want to change oil more often. I do 5000 miles. Again, probably more than needed, but oil/filter deals at Autozone make it cheap.

  • avatar
    jtk

    I wonder how this car has been driven? I also have a Skyactiv 3 with about 70,000 miles, and I have none of these issues (so far). But I drive on the highway for about 45 minutes a day. My theory is that short trips are part of the problem.

    Also, according to my owners’ manual the plugs should be changed at 75,000 miles.

  • avatar
    thegamper

    I love how every Mazda thread, be it about engines, design, driving experience, or even advertising tag lines will eventually involve someone bringing up rust. I have owned 3 Mazda’s, granted, none for over 100k miles, but found them all to be fairly trouble free with the exception of carbon buildup issues on the turborcharged Mazdaspeed6. Zero rust on any of them, but yes, I too have seen a rusty Protege. Go to any auto site dealing with specific models/brands and you will see a host of issues that creep up, Ive seen your favorite models and brands stranded on the side of the road or on flatbeds, just like everyone else who has driven for a decade or two. The point being, and maybe I am preaching to the wrong crowd, that anecdotal evidence is just that. Personally, this is why I stay away from used cars. You never know what sort of life they have had.

    • 0 avatar
      gtem

      Sorry but the in this case there are mountains of anecdotal evidence. There isn’t a gen 1 Mazda3 for sale in Indy right now on craigslist that doesn’t have some degree of cancer on the rear quarter panels. Again, in my friend’s case it’s an 09. Pathetic, to be honest.

      • 0 avatar
        thegamper

        I see it on Proteges all the time, but generally not the Mazda3s here in Michigan. Still, I think even if you are using anecdotal evidence, Mazda’s rust problems are behind them. On a 10 year old car, assuming the 09 is roughly 10 years from manufacture, some rust isn’t that unexpected. Totally rusted out to the point the sheet metal is extensively perforated, I would have to agree that it is pretty bad and unacceptable. Even so, all it would take on most cars is a deep scratch t o turn into extensive rust over 10 years in northern climate.

        • 0 avatar
          gtem

          “not the Mazda3s here in Michigan”

          Really?

          Michigan mazda3s:

          ’06 rear dog leg totally gone:
          https://grandrapids.craigslist.org/cto/d/2006-mazda-3-hatchback/6557504663.html

          ’08 A lot of bubbling creeping onto the quarter panel, that inner fender is totally shot by my estimation:
          https://battlecreek.craigslist.org/cto/d/2008-mazda-mazda-3/6545804867.html

          ’08 nothing obvious in the photo right? But look closely and that’s a bit of a bubble starting, again, a close look on the folded in part will doubtlessly uncover some serious rot:

          https://kalamazoo.craigslist.org/cto/d/2008-mazda-3-manual/6548235896.html

          Another ’08 in full bloom:
          https://detroit.craigslist.org/wyn/cto/d/2008-mazda3-grand-touring/6559577488.html

          Piece de resistance:
          https://detroit.craigslist.org/wyn/cto/d/2004-mazda-3-sedan/6536721245.html

          • 0 avatar
            thegamper

            Didn’t say it doesn’t happen. Just said I don’t see them. Your examples are all at least 10 years old. How many thousands of Mazda 3s do you think live in Michigan and were sold over a 10 year period? I’m sure you can find 10 year old examples of rust on most any model of car. Did you look for 3s with no rust? Did you look to see what other 10 year old vehicles also have rust aside from mazdas? Just sayin, if you look for it, of course you will find it. Personally I don’t have the time/desire to put together any empirical data to prove my point. So….. you win if you want.

          • 0 avatar
            gtem

            @thegamper
            Challenge: find me as many rusty ’08 Civics and Corollas on these same craigslists, or even Cobalts.

            You claim that mazda3s aren’t predisposed to rust because you’ve owned a few (self-admittedly not long term), are roundly proven wrong with empirical evidence that took all of a 3 minute glance at craigslist, and are now picking up your toys and leaving. Sounds good.

    • 0 avatar
      WheelMcCoy

      I suppose there’s more anecdotal evidence for rust than no rust, although I come down on the side of no rust and trouble-free operation of my 2010 Mazda3. I’m in the snow belt, but the car is mostly garaged and currently has 65k miles. I see 2 other 2nd gen Mazdas — a hatch and a 2.5L sedan — in my neighborhood and they appear rust free as well. So perhaps the tide is turning.

      • 0 avatar
        gtem

        I do suspect that the “smiley” 2nd gen 3s turned the corner on corrosion engineering.

        • 0 avatar
          rpn453

          Yeah, I can’t recall noticing any rust on the 2nd gens yet, but the first gen 3s did tend to develop serious rust before anything else of the same age around here.

          Mazda deserves the flak they take for that, but it should start fading soon enough. Honda was just as bad only a few years prior and I don’t hear anything about them anymore.

          My ’04 is pretty much rust free unless you look really closely. I’ve been soaking the doors and fenders in Rust Check twice a year for the last decade or so.

  • avatar
    raisingAnarchy

    It might be worthwhile to send an oil sample to Terry Dyson of DysonAnalysis. He’s helped me immensely with diagnosing issues with my PCV system on my WRX STI. He would at least be able to answer questions about how the EGR is working in combination with your ring seals.

  • avatar

    There is good article with pictures and photos, and yes it is about Mazda engine:

    https://toolsinmotionauto.ca/blog/?p=218

    “The photo above is from a Mazda that we serviced this week, and is the worst example of this build-up that we have seen to date. This engine had less than 150,000 kilometers on it, and a bad misfire that was due in part to the valve issues.”

    • 0 avatar
      ToddAtlasF1

      “However, moving the fuel spray from the intake manifold to inside the cylinders had an unexpected conseqeuence: bad deposit build-up on the intake valves.”

      Unexpected? Anyone that didn’t expect this was stupid enough to vote for higher fuel efficiency instead of shopping for it.

      • 0 avatar
        dantes_inferno

        >“However, moving the fuel spray from the intake manifold to inside the cylinders had an unexpected conseqeuence: bad deposit build-up on the intake valves.”

        >Unexpected? Anyone that didn’t expect this was stupid enough to vote for higher fuel efficiency instead of shopping for it.

        And that (DI carbon issue) is the GIANT elephant in the room that the automotive industry doesn’t want anyone to notice.

    • 0 avatar
      rpn453

      I suspect that was the turbo DI engine in the CX-7, Speed3, and Speed6. It would be surprising if somebody had the valves gum up so badly in less than four years with 30k+ km a year usage.

      I advised my buddy to avoid the CX-7 because of that engine and he got a CX-5 instead. I hope they’ve got this stuff figured out well enough that Top Tier fuel can keep it running.

  • avatar
    stuart

    I researched this before I bought my ’17 Mazda.

    Mazda claimed that the coking was minimized by keeping the intake valves above 400F:

    http://www.motoiq.com/MagazineArticles/id/2105/pageid/3529/131-compression-and-40-mpg-on-87-octane-fuel-introducing-mazdas-skyactiv-technology.aspx

    There seem to be dozens of pictures of badly-coked German DI engines on the web, but pictures of coked Mazda DI (Skyactiv) valves are rare. @InsideLookingOut posted one such link, but the article is mostly about useless cleaning products; the article omits any mention of the year or whether it has a turbocharger. Here’s a link to a non-turbo Mazda DI engine with some valve build-up:

    https://www.miataspeed.com/blogs/news/walnut-blasting-intake-valves-our-2016-skyactiv-g-nd-miata

    While the owners of the above engine had it cleaned with walnut blasting, it’s actually not very bad. When this subject comes up on the web, it’s usually about an engine with a severe issue, like this:

    http://tyspeed.com/bmw-n54-n55-s55-intake-valve-carbon-blasting

    This forum posting has links to several videos about valve cleaning (none are Mazda):

    https://www.corvetteforum.com/forums/c7-tech-performance/3717271-lt1-gdi-owners.html

    Bottom Line: this is a real problem for many makes, especially German. It seems pretty rare on Mazdas.

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