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Spark Plug Replacement

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by satwood, Feb 5, 2015.

  1. satwood

    satwood Member

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    I just replaced the spark plugs on my 2007. I was amazed at how hard they felt trying to spin them out of the engine. It felt like they were tearing the threads as they came out. They were in there for 120K miles and I don't remember how hard it was to take the last ones out but this really worried me. When I got each one out, the threads were clean, no metal, and the new ones spun in fairly easy but not quite by finger so I don't know what the deal was. I did use a very thin layer of anti-seize on the last ones and on these so I did not expect this issue.

    Anyone else have this problem or know if I should or should not be using anti-seize on them?

    Thanks for the help - Steve
     
  2. 69shovlhed

    69shovlhed Surly tree hugger

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    some folks say anti-seize gums them up and don't use it.
     
  3. alekska

    alekska Active Member

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    They come out hard because the bottom part of the thread has deposits from combustion build up over time

    Alex
     
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  4. bisco

    bisco cookie crumbler

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    some recommend removing and replacing at 60,000 just because they're in there too long. how many miles on her, steve?
     
  5. JC91006

    JC91006 Senior Member

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    It's recommended that you don't use antiseize on the plugs. Most people get the same experience when removing the plugs at 120k. All seems to be normal
     
  6. satwood

    satwood Member

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    Total miles on the car about 220K These plugs were in for 120K of them. I'll try to change them again before 300K the to see if that's any better - thanks
     
  7. satwood

    satwood Member

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    Thanks, I appreciate that feedback. I've read some opinions both ways. I guess using anti-seize is an old habit I have a hard time breaking.
     
  8. PriusGuy32

    PriusGuy32 Prius Driver Extraordinaire

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    "Spark plugs"?! Are we even allowed to call them that here? o_O

    I thought since the ignition coils were "igniters", and the brake rotors are "discs", then shouldnt the spark plugs have some proper name that defeats general automotive repair dialect and adheres to the nomenclature that only the highest engineers and bean counters at Toyota use??

    Im waiting for the day around here that somebody calls a tire a "Polymer orb" or something like that :LOL:
     
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  9. sorka

    sorka Active Member

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    I just went through this myself last month. First set I changed at 100K miles and had no problem getting them out. Second set was last month at 184K miles and I nearly destroyed the plugs taking them out. The threads on the plugs were quite torn up. Fortunately the cylinder head plug threads looked fine. Since I didn't use anti seize the last time and they were so tough taking out, I did use it this time.

    It's likely related to deposits. My Prius started consuming oil at around 100K miles. By the end of last year it was consuming about a qt every 1500 miles. I did a bunch of things all on the same day which is not a good idea if you one of them works because I have no idea what I did that made a difference:

    • Changed PCV valve.
    • Changed spark plugs.
    • Added 1/2 qt of MMO to engine oil
    • Added 4 oz of MMO to gasoline
    Then I drove it for about 500 miles and then:
    • Changed oil
    • Added 12 bottle of Techron
    Now we're about 187.5K miles and not a drop consumed. The oil level is exactly where it was when it was changed at 184.5K miles.

    I bought high mileage engine oil which I was going to try next but haven't used it yet because the consumption seems to have stopped.

    I'll probably to 60K mile intervals on the plugs. It was just too scary how hard it was to get them out. Maybe a dos of PB blaster overnight in the spark plug holes before removing them?
     
  10. Avi's Advanced Automotive

    Avi's Advanced Automotive Independent hybrid repair shop

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    Back in airplane mechanic school, my instructor told us that anti seize makes spark plugs harder to remove, but we still has to use it because the FAA said so.

    Avi
     
  11. uart

    uart Senior Member

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    Sparkplugs? You mean the PSPDDs (plug shaped plasma discharge devices) don't you. :p
     
    #11 uart, Feb 8, 2015
    Last edited: Feb 8, 2015
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  12. uart

    uart Senior Member

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    Yeah someone posted a link to an NGK document last time this came up, where they (NGK) were saying that anti seize is not needed with the plated threads they use on modern spark plugs. (y)
     
  13. PriusGuy32

    PriusGuy32 Prius Driver Extraordinaire

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    :LOL::LOL: See I knew we couldnt say "spark plugs" anymore!! lol
     
  14. Britprius

    Britprius Senior Member

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    I uphold your right to say it as many times as you like. Just don't use it on technical forums like PC.

    John (Britprius)
     
  15. wjtracy

    wjtracy Senior Member

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    I had the same hard spinning...felt like I was reeling in a big shark and he was fighting me the whole time.
    There was no obvious "give" when I first loosened them, just a slow drag the whole time.
    Of course I waited to about 130k miles.

    The first plug, I thought maybe I was twisting the top off or something. But after it finally came out OK, I just realized that was the way it was going to be. Well I am hoping not to do it again, but at least on Gen2 is easiler than Gen3 to get to the plugs.

    PS- I did NOT use anything on the plug threads
     
    #15 wjtracy, Feb 8, 2015
    Last edited: Feb 8, 2015
  16. valde3

    valde3 Senior Member

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    Normally it being easy to open at first but then getting hard to open means it has carbon buildup on threads where they go into combustion chamber. Many times if you just turn it back in fort in the easy to turn area, at begin it might be less than 1/16 turn, buildup will break off. This is better than just forcing it out since forcing might broke threads in aluminum head.
     
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  17. exstudent

    exstudent Senior Member

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    Toyota & NGK make no mention of anti-sieze, perhaps b/c there is no way to quantify the amount to be applied to each spark plug? Imagine if it was said apply "a little," to upper portions of the threads? Too much interpretation, and liability.

    Denso, an OEM spark plug, actually states this (LINK):
    Note: The installation torque values shown above apply to new spark plugs without lubricating the threads. If threads are lubricated, the torque value should be reduced by approximately 1/2 to avoid over-tightening.
    * 1N*m = 0.1020 kgf*m​

    Denso listing this, would be open to some liability, if anyone had a problem. But this is assuming they have the resources to finance what would be a costly law suit.
     
    #17 exstudent, Feb 8, 2015
    Last edited: Feb 8, 2015
  18. Britprius

    Britprius Senior Member

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    Denso is a huge multinational company, and like any such company carry insurance for any possible risks. They work with all the large car companies in R&D for there products supplied to those companies. A law suit from one or more car customer (s) would not be a threat to there resources.

    John (Britprius0
     
  19. exstudent

    exstudent Senior Member

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    They was meant as the consumer. A law firm would only probably take it on if the individual had millions to finance this endeavour. Or if enough consumers had issues and a law firm smelled blood in the water, would they take it on contingency, like the most recent Takada air bag issues, GM ignition issues, and Toyota acceleration issues.

    Yeah, Denso has plenty of resources to setitle or fight. Most ordinary individual consumer(s), lack the millions to start and sustain a fight.
     
    #19 exstudent, Feb 8, 2015
    Last edited: Feb 8, 2015
  20. Avi's Advanced Automotive

    Avi's Advanced Automotive Independent hybrid repair shop

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    Maybe they take that position because some manufacturers may suggest lubrication/anti seize while others might not? That statement would fit both. I'll tell you one thing, I've taken plenty of factory spark plugs out of Prii and have never seen the factory use anti seize.