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Gen 2 Head gasket failure? Photos included

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by s2p2e, Sep 9, 2021.

  1. s2p2e

    s2p2e Junior Member

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    I checked spark plugs based on rougher than usual engine starts/stops and found oil on spark plug in the second chamber from the left. So, I changed the valve cover gasket and spark plugs, didn't fix it. Now getting oil on spark plugs 2 and 3, and rough stops/starts are gradually getting rougher. It has started burning oil.

    Does anyone have a clue of what to try other than replacing the head gasket? I understand it's a rare problem for Gen 2's, but does happen. I've tricple checked that the replacement valve cover gasket was seated properly

    Photos (all numbering from left to right when facing the engine bay)

    Spark plug 1:
    SP1.jpeg

    2:
    SP2.jpeg

    3:
    SP3.jpeg

    4:

    SP4.jpeg

    A look inside the cylinders (I'd be happy to repeat these with the spark plugs removed if that would be helpful):

    1:

    20210909_115354_exported_1470.jpg

    2:

    20210909_115316_exported_3866.jpg

    3:

    20210909_115259_exported_14.jpg

    4:

    20210909_115332_exported_991.jpg


    1:

    1.jpeg

    2:

    2.jpeg

    3:

    3.jpeg

    4:

    4.jpeg


    superior.jpeg

    lateral.jpeg

    Hopefully that's not an overload! I figured too much info would be better than not enough.
     
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  2. JC91006

    JC91006 Senior Member

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    I believe you can fix that by simply replacing the valve cover gasket, it has gaskets for the rings around the spark plugs too.
     
  3. s2p2e

    s2p2e Junior Member

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    Good thought, but I already replaced it along with all of the spark plugs. That was my first line of attack
     
  4. JC91006

    JC91006 Senior Member

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    So that should fix that problem
     
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  5. SFO

    SFO Senior Member

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    How many miles on the vehicle?

    How many miles on the spark plugs pictured above?

    Do you have any misfires being reported via the OBD2 port?

    Try cleaning up the outside of the COPS (coils), and you may want to run some PEA in the gas tank.
     
  6. s2p2e

    s2p2e Junior Member

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    Just to be clear, I replaced those about a month ago and these photos were taken yesterday. Looking for advice because I expected that to solve the issue and it didn't
     
  7. s2p2e

    s2p2e Junior Member

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    She's nearly at 200K, and I replaced the spark plugs along with the valve cover gasket about 2000 miles/a month ago. No misfires reported via OBD2. I appreciate the advice, will do!
     
  8. JC91006

    JC91006 Senior Member

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    I had a car with 300k miles on it with a similar issue, the valve cover gasket was what leaked oil into the plugs.
     
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  9. s2p2e

    s2p2e Junior Member

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    Right, that was my first thought as well. Unfortunately that isn't the case here.
     
  10. SFO

    SFO Senior Member

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    There appears to be quite a bit of blow-by, especially on plug #3, did you purchase those plugs online? (they could be fakes)
     
  11. s2p2e

    s2p2e Junior Member

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    Sure did, actually. They came from a seller with 99.1% positive feedback and tons of transactions, but I suppose they could still be counterfeit. That would be really unfortunate.

    Here are the ones I bought: 4PCS Spark Plugs SK16R11 Fits For Toyota Corolla Matrix Prius 90919-01240 US | eBay
     
  12. SFO

    SFO Senior Member

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    Check out this post about fake plugs : My 2010 Prius, It's official, 1qt oil every 4,000 miles | Page 5 | PriusChat

    When you put the old plugs back in, does that change the observed start/stop behavior?

    Have you inspected the PCV for cleanliness and proper function?
     
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  13. s2p2e

    s2p2e Junior Member

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    Thank you for that. I should have known better based on the price, but the strong review history persuaded me. They do seem to be well-made fakes. The only tells I could identify (aside from the non-authorized retailer and low price) are the smaller crush washer groove and that the surface of the hexagon reveals a copper color underneath when scratched heavily. Regrettably, I did not retain the old spark plugs.

    I haven not checked the PCV but may just go ahead and replace it.
     
  14. PriusCamper

    PriusCamper Senior Member

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    You gonna do a compression test? If that checks out I'd suggest something went wrong on your valve cover install and that's the source of the problem.
     
  15. edthefox5

    edthefox5 Senior Member

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    Must use a factory gasket. And put a little black atv dab on the 2 joints where the timing cover meets the block. Buy plugs from Toyota.

    I use Olathe toyota.com

    And its remarkable it has not needed a cop or 2 replaced from misfire. I replaced all of mine just because of miles and the car ran 100% better. So there is some detriment of cop performance before it gets so bad it misfires.

    factory cops are expensive. $100 each. I was buying one every 6 month's leading up to the day I threw them in.
    It got a new valve cover gasket new sparkplugs new plugs new cops new pcv and its 2 hoses. Ran like a new car. Good for another 100,000 miles.

    By the looks of your engine its had a dino oil life so the throttle body will be extremely clogged.
    See all that brown stuff on your engine that's burnt oil fumes that has baked onto your engine. Synthetic oil does not do that. That's all pumped directly into the throttle body.

    Oh and the best time to replace the pcv valve is with the V cover off.
    It's easy to break the case with a wrench with a cover on. Deep socket only no box wrench. many posts about broken cover.
     
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  16. ChapmanF

    ChapmanF Senior Member

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  17. PriusCamper

    PriusCamper Senior Member

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    Sums it up perfectly... And I'm still trying to find someone to show me a failed PCV valve? I haven't seen one that was legitimately failed since I worked in an auto shop in High School in the 1980's when I was working on a really grimy 30 year old car.
     
  18. SFO

    SFO Senior Member

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    It may not need replacing, check for the 'rattle', then exhale to see if it seals in one direction and blows through the other.

    Spray something inside the PCV to clean any crude out before reinstalling.

    Did you notice any oil on the inside of the rubber hose where it connects to the PCV?
     
  19. s2p2e

    s2p2e Junior Member

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    Would like to soon, going to start with replacing the counterfeit plugs (and PCV valve since it's readily accessible right now and inexpensive)
     
  20. s2p2e

    s2p2e Junior Member

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    Thanks for all of the input! I'm going to start by swapping the counterfeit Denso plugs for authentic ones and replacing the PCV valve, will look into COP replacements. Yes, unfortunately it has had dino fuel up until a couple of months ago when I started doing my own oil changes, full synthetic now. I cleaned the throttle bottle and mass airflow sensor very thoroughly 5-6 months ago.