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Newby could use some help with changing spark plugs.........

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by AEC916, Apr 18, 2020.

  1. AEC916

    AEC916 Junior Member

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    2010 w/153k. I've done some minor wrenching and am about to tackle replacing the plugs on my trusty steed. My tool box is pathetic right now and wondering if you guys can provide a list of tools and materials I will need to get the job done (e.g., wrench sizes, do I really need to buy a torque wrench?, 1/4 inch battery powered impact gun I case a plug is stuck, any special pliers for the clips, etc,,,,). Also, the plugs themselves..... seems like most use the NGK Iridiums, but Autolite makes an Iridium tipped plug for the car at almost half the price. Has anyone tried the Autolite's? Thanks in advance.
     
  2. bisco

    bisco cookie crumbler

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    start another thread with sac in the title. lots of members out there who would be willing to come over, or you could go to a meet up.
     
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  3. pjksr02

    pjksr02 Active Member

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    Be aware that the specified Denso plug has changed since 2010. It seems you can only find it at the dealer. My preference is to use these, and they cost less than $10, though I don't have an argument against using NGKs.

    Now, more importantly, while you have the wipers and cowl off, you're planning to give the EGR cooler and the rest of the EGR system a good cleaning, right?
     
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  4. ChapmanF

    ChapmanF Senior Member

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    Fussing with critical, possibly stubborn threads, in an aluminum cylinder head that you don't want to replace ⇒ yes.
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Good point. Orignal plug spec'd in Owner's Manual is SC20HR11. Revised (slightly hotter) plug is SC16HR11.

    I'm not sure about that. If you have a reputable local automotive retailer you use, check with them; I'm sure they can get the plug. Just stay clear of sketchy online sources.

    I would recommend:

    1. 1/4" drive torque wrench. Torque spec is 15 foot/pounds with clean/dry threads.
    2. 3/8" ratchet wrench, with at least 6" of extension, and a 14 mm spark plug socket (with rubber sleave to grip the plug). Alternately, just a regular 14 mm deep socket and a good magnetic pointer, something to grip the thread, lift it gently in/out. When using a spark plug socket, maybe run masking tape around the extension joints, it's not uncommon for the joints to separate when you're trying to pull the socket off the plug, which is a pain.


    Also, watch @NutzAboutBolts spark plug video if you haven't;, it's linked in a thread pinned at top of this forum.

    The attached Repair Manual excerpt shows the spark plug torque. It's also a testament to the brain-dead formatting: the last page, which shows the torque value, is from a whole other section of the manual, miles away from the rest of the spark plug info.
     

    Attached Files:

    #5 Mendel Leisk, Apr 18, 2020
    Last edited: Apr 18, 2020
  6. Raytheeagle

    Raytheeagle Senior Member

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    Maybe after the pandemic;).

    We'll see what the new normal holds(y).
     
  7. AEC916

    AEC916 Junior Member

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    Thanks for the suggestion, but we're pretty much locked down here. Which is why BTW, I have time to do this now......

    Ok, tks. Going to go with the $19.99 3/8" model from HF, since I may not use it again.

    This is great, tks. Question, is there a reason for 1/4" torque wrench when everything else is 3/8"? Thanks!

    Yeah, I've looked at the EGR video also and would love to do it but I'm pretty sure I'd get in over my head.
     
    #7 AEC916, Apr 18, 2020
    Last edited by a moderator: Apr 18, 2020
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  8. JC91006

    JC91006 Senior Member

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    Bisco says, "Lots of members out there who would be willing to come over". Well I don't know about "lots", maybe possible to find one.....and I don't think it'll be easy find that one.

    Watch some youtube videos on replacing spark plugs, a walk in the park if you have a couple hours to spare. Make sure you use either the Denso or NGK spark plugs, nothing else will be quite the same.
     
  9. Peter123

    Peter123 Active Member

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    I used dealer supplied Denso plugs, which failed almost immediately.
    Then I used NGK 4912, which I bought from Rockauto. They worked just fine.
     
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    9/16" works too, what I have. Mine is brand-new, and the rubber collar grips so hard it remains on the plug when you torque it and try to pull out on the extension. If that's your setup and you're not sure, tape the extension to socket connection well, will prevent that pull-off.

    Something weird there, maybe counterfeit. Did you let them know? That should not happen. Do you still have the failed plugs, because I've heard there's some tell-tale clues, the electrode side electrode is just plain steel, not like the genuine Densos?
     
  11. bisco

    bisco cookie crumbler

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    wow, you folks in cali are really freaked out by the virus. i would happily help someone with masks and social distancing
     
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  12. Mendel Leisk

    Mendel Leisk Senior Member

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    Basically because 15 foot pounds is pretty low, and for a 1/4" torque wrench, that value would be somewhere in the middle of it's range. Any torque wrench tends to be less accurate near the ends of it's range, in particular the low end. A 1/2" drive torque wrench might have values 10 ft/lb to 150 ft/lb, and 15 ft/lb is so close to the bottom as to be suspect.

    A 3/8" drive torque wrench would probably be fine too. They'll have values going down to 5 foot/pounds.

    FWIW a 1/2" drive torque wrench is all I had for many years, and I got away with it, doing spark plugs.

    Something to note too: 3/8 and 1/2 inch drive torque wrenches are usually in foot pounds, whereas 1/4" drives tend to be in inch pounds. If you're using an inch pound torque wrench, to set it to 15 foot pounds you'd dial in 180 inch pounds (15 times 12).

    I see the ranges on mine are:

    20-240 inch pounds
    5-80 foot pounds
    20-150 foot pounds

    image.jpg
     
    #12 Mendel Leisk, Apr 18, 2020
    Last edited: Apr 18, 2020
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  13. Grit

    Grit Senior Member

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    The state government here are much stricter. This is their agenda to keep us indoor from driving to show reduction in carbon output and ushered the homeless into hotels which repeatedly trashed public bathrooms and parks thinking homeless will take care of hotels while the camp fire survivors continue to live in their bank loaned RVs parked at the airport here.
     
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  14. Raytheeagle

    Raytheeagle Senior Member

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    How are you going to stay more than 6 feet away from someone as you work in the engine bay:whistle:?

    And also I'm keepin to myself and hoping others do too;).

    We need testing, but keeping to the physical distancing will help limit exposure(y).
     
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  15. AEC916

    AEC916 Junior Member

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    Plugs are in, sounds much smoother. Wasn't that hard thanks to you guys! I haven't put everything back yet cause I want to sleep on the EGR project. Here's a pic of the worst plug. Doesn't look too bad for an original plug with 153k miles.
     

    Attached Files:

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  16. pjksr02

    pjksr02 Active Member

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    Torque wrenches: there are 3/8"-drive "micro-torque" wrenches, too. That's what I have, from Craftsman.
     
  17. Rebound

    Rebound Senior Member

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    A 1/4” torque wrench is a bit more accurate at the low torque values.
    Harbor Freight sells a simple digital torque meter you can use instead of a torque wrench
     
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