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Spark plug broke off

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by CharlesPrius, Jun 2, 2019.

  1. ChapmanF

    ChapmanF Senior Member

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    That is always the reason experienced mechanics do things.
     
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    It wouldn't hurt to run a vacuum hose down there, and do a borescope inspection after. Even if the vacuum hose won't allow a large fragment to pass, it might grab it, and allow you to lift it out.
     
  3. jb in NE

    jb in NE Senior Member

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    True. I think the mechanics look at what came out with the plug, and if there is only a small amount of ceramic missing, for example, they know it won't hurt the engine and just blow out what they can through the plug hole. If there is a big chunk missing, they may go fishing first.
     
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  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Don't forget, if one set of valves is open you can use a combination of shop vac & compressed air to do a blow-through method. You get a few choices, depending on access, ease of manifold removal etc but those are real options when you know there's something harder than a piston crown in there. Still faster than pulling the head.

    From the timing reported it doesn't sound like this was necessary in this case.
     
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  5. Greenteapri

    Greenteapri Active Member

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    Late to the party. I'm happy to read it worked out in the end for you OP. I've known those feelings of hopelessness working on cars, too. Not fun. This is a testament not only to work on your own car but to know a competent mechanic when SHTF. (y)

    Happy driving.
     
  6. ASRDogman

    ASRDogman Senior Member

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    A better way would be to put grease in the slots of the tap. The grease catches 98% of the aluminum.
    Then an air hose to blow out anything debrief that may get through the grease.
     
  7. Boffin

    Boffin Member

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    Another way to remove crap from a cylinder without pulling the head:
    Get a length of cotton cord and cover it with grease. Set the piston of the dirty cylinder to TDC. Stuff the cord into the spark plug hole, stuffing as much as possible into the hole, but always leave enough that you can pull it out. The idea is to fill the top of the cylinder with that sticky string. Pull out the string. Wipe it off. Regrease it if necessary. Repeat until the string comes out clean.
     
  8. CharlesPrius

    CharlesPrius Member

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    When it dismounted from tow truck, mech didn't think twice about starting it and driving it into the garage. I was like "whoa whoa i heard that might ... " but ice had already cut on. i didn't hear any awful screeching noise so it was then i knew that little or no ceramic had fallen down in there. Good to know that the little bits would get crushed up or blown out pretty easily. i've read other posts -- most here on PC -- that said ceramic bits could be fatal...
     
  9. frodoz737

    frodoz737 Top Wrench

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    I love my job. Now try getting a broke off igniter out of a $5 million engine. That adds to the gray count.

    Word for wise... always use a amount of high temp anti-siese on the threads of your plugs and just reduce your torque by 20 percent. For 3rd Gens that comes out to 12 ft/lbs or 144 in/lbs.

    Glad to hear your problem was an easy fix CharlesPrius. Most are.
     
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  10. Greenteapri

    Greenteapri Active Member

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    Why 20%? Why not 30?
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    20% Reduction is not a bad guesstimate. Pocket Ref by Thomas J. Glover has a table for torque reduction. A few values:

    Black Oxide: 100%
    Steel (clean, dry, non-plated as-received condition): 100%
    Silver grade anti-seize: 90% (likely case)
    N-1000 anti-seize: 85%
    Zinc plating (electroplated): 85%
    C5A, copper-graphite based anti-seize: 80%
    Motor oil (SAE20W): 80%
    N7000 anti-seize: 80%
    Motor oil (SAE40W): 75%
    Zinc anti-seize: 75%
    Graphite: 70%
    Molybdenum grease: 70%
    Oil (light weight): 60%
    Oil (heavy weight): 50%
    Wax (extreme pressure): 50%
    Never-Seez: 45%
    Premier thread lubricant: 45%
     
  12. StarCaller

    StarCaller Senior Member

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    worth WAY more than what you pay for it /
    [​IMG]
     
  13. jb in NE

    jb in NE Senior Member

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    You can also do the "turn of the nut" method. Many sparkplugs specify that after the gasket contacts the head, you tighten an additional 2/3 or so. This provides adequate gasket crush and is independent of the torque applied to achieve the crush.
     
  14. Greenteapri

    Greenteapri Active Member

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    This is very similar to the technique I use.

    NGK does not recommend using anti seize.

    Denso (which Toyota uses) recommends that the torque spec be reduced by 1/3 if you absolutely must use anti seize lube.

    20190607_113811.jpg

    I never leave home without it.
     
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  15. SteveSco

    SteveSco Junior Member

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    A tip is to remove the spark plugs when the engine is hot, they come out easier and there's less chance of breaking a plug in place
     
  16. melvinpmanuel

    melvinpmanuel New Member

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    Hello all...I have another issue after replacing the spark plugs. After two weeks of replacing ( driven approx 150 miles), I was getting noise from the engine. The engine light became ON. The noise was coming from the engine cylinders and I suspected some issue with the spark plugs. I remove the plugs one by one and all three of them was broken. Please see the attached for the broken spark plugs. What may be the reason for this behavior? Did I do some mistakes while replacing it? I remember, I have tighten a screw a little bit, which I found at the top of the engine compartment, in between the first and second spark plugs (From the left).
    Please help me to resolve this issue..
    Thanking you
    Melvin
     

    Attached Files:

  17. ASRDogman

    ASRDogman Senior Member

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    I notice the electrode missing. The piece at the spark end of the plug....
    Those plugs look like they have been in a while. Where they new when you put them in?
    Over tightening would not have broken the plug where you say they are broken.
    It's hard to brake them in that spot. I think maybe a defective set? Where did you get them?
    You could put the older ones in so you can drive it, and take them back to the place you got them.
    Then make sure they are NEW.
     
  18. Mendel Leisk

    Mendel Leisk Senior Member

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    Maybe counterfeits?
     
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  19. ASRDogman

    ASRDogman Senior Member

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    I thought that also, but they are NGK's....
     
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  20. ChapmanF

    ChapmanF Senior Member

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    What would be printed on a counterfeit NGK?
     
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