1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Replacing ignition coils with spark plug change?

Discussion in 'Gen 3 Prius Audio and Electronics' started by sadhu, Aug 21, 2019.

  1. sadhu

    sadhu Junior Member

    Joined:
    Feb 22, 2018
    17
    5
    0
    Location:
    New Mexico
    Vehicle:
    2010 Prius
    Model:
    III
    I am replacing my spark plugs and wondered if it's smart to change out the ignition coils at the same time? I have 111,000 miles on the engine running with the original ignition coils.
    Thanks
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    i don't think so, most coils last a long, long time, from what i have read here
     
    sadhu and Mendel Leisk like this.
  3. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,470
    38,103
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Reading between the lines: you're thinking getting to the plugs is so much work, you don't want to repeat it? I wouldn't sweat it, second time it goes faster.

    Agree with @bisco too, it's not like a water pump, a critical item where failure could damage the engine (I think...). I would just replace them if/when they fail.
     
    sadhu likes this.
  4. sadhu

    sadhu Junior Member

    Joined:
    Feb 22, 2018
    17
    5
    0
    Location:
    New Mexico
    Vehicle:
    2010 Prius
    Model:
    III
    You hit the nail on the head! First time changing the plugs! I have watched the Nuts and Bolts guys video and think I can handle it. Thanks for the advice. Prius Chat is a must for us do it yourselfers!
     
    Mendel Leisk likes this.
  5. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,470
    38,103
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Regarding the video, the Repair Manual spec for spark plug torque is 15 ft/lb, presumably with dry threads *. If you use anti-seize, I would say very sparingly, maybe apply it then wipe it off with a rag: that'll leave a slight amount in the grooves. Then reduce torque to 12~13 ft/lb. Or hey: 15 ft/lb and dry threads.

    * In the video they really lay the anti-seize on thick, and he mentions 20 ft/lb. I'm reluctant to disagree, one of them at least was a dealership mechanic IIRC, but yeah maybe in this case.

    Attached are a couple of excerpts regarding the spark plugs. It is goofy: the main section on spark plugs makes no mention of spark plug torque. That is way across the document in another section. Both sections attached.
     
    sadhu likes this.
  6. ILuvMyPriusToo

    ILuvMyPriusToo Senior Member

    Joined:
    Dec 4, 2014
    778
    514
    0
    Location:
    Outside Philly, PA
    Vehicle:
    2009 Prius
    Model:
    II
    Note the torque on the coil bolts is considerably less. I don't have the spec in front of me but the first time I changed my plugs on my Gen II I did manage to snap one of those coil bolts as I wasn't expecting how low it really was. :eek: Luckily, once the tension was off, I was able to extract the broken bit by hand. :whistle:
     
    sadhu likes this.
  7. sadhu

    sadhu Junior Member

    Joined:
    Feb 22, 2018
    17
    5
    0
    Location:
    New Mexico
    Vehicle:
    2010 Prius
    Model:
    III
    Thanks for the info and the PDF's.
     
    Mendel Leisk likes this.
  8. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,470
    38,103
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    The coil bolt is just a locator/hold-down bolt. The big issue I think, is the repair manual lists an inch/pound torque spec for that bolt, which is twelvefold less than a foot pound. Novices have dutifully set a 1/2" drive torque wrench to the value, but in foot/pounds, and naturally snapped the head off.

    Yeah just use common sense, lol. I wouldn't use a torque wrench, just tighten it with a ratchet wrench, one-handed on the wrench fulcrum: that'll keep you out of trouble.
     
    sadhu likes this.
  9. Zeppo Shanski

    Zeppo Shanski Active Member

    Joined:
    Feb 5, 2019
    282
    150
    0
    Location:
    Chicagoland
    Vehicle:
    2005 Prius
    Model:
    Base
    WOW ... Just for fun I looked up the coils on mine; 2005 Gen2. ... Those bad boys are $22 a pop + shipping. ... I wouldn't replace them unless you jacked one up in the process of changing the plugs.
     
    Mendel Leisk and sadhu like this.
  10. sadhu

    sadhu Junior Member

    Joined:
    Feb 22, 2018
    17
    5
    0
    Location:
    New Mexico
    Vehicle:
    2010 Prius
    Model:
    III
    Great info, guys... any suggestions on what type or brand of spark plug I should use?
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,470
    38,103
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    That's not bad. Up here if you just walk into the dealership parts department, and ask them flat-footed for just the spark plugs, it's not uncommon to hear numbers like $24 apiece. Canadian dollars, but...

    I go to a small automotive specialty shop; they're very competent, have or can get most anything. There the plugs are a mere $16~17.

    Owner's Manual, page 562, says: DENSO SC20HR11. I believe though, sometime since publication, Toyota revised that to SC16HR11, which is slightly hotter. Verify with dealership parts department, but you can buy that plug anywhere.

    Automotive specialty stores typically are cheaper. There's been talk of counterfeit plugs, especially online purchase, EBay. I'd be cautious. I think your best bet would be an automotive specialty store with a good reputation, been around for a while.
     
    #11 Mendel Leisk, Aug 23, 2019
    Last edited: Aug 23, 2019
    sadhu likes this.
  12. Zeppo Shanski

    Zeppo Shanski Active Member

    Joined:
    Feb 5, 2019
    282
    150
    0
    Location:
    Chicagoland
    Vehicle:
    2005 Prius
    Model:
    Base
    Plugs ...

    If it's me ... I'm going w/ the NGK 4912 Laser Iridium ... about $7.50 / pop.

    I go w/ a little touch of anti-seize and twist nice and snug hand-tite.
     
    sadhu likes this.
  13. Kenny94945

    Kenny94945 Active Member

    Joined:
    Mar 24, 2016
    758
    387
    0
    Location:
    Sausalito
    Vehicle:
    2016 Prius v wagon
    Model:
    Four
    My vote: I would not replace the coils...just replace the plugs.
     
  14. sadhu

    sadhu Junior Member

    Joined:
    Feb 22, 2018
    17
    5
    0
    Location:
    New Mexico
    Vehicle:
    2010 Prius
    Model:
    III
    Update ...I just changed out my plugs and found it a fairly simple procedure.But, I found two things that are different when changing these plugs compared to my 350cc V8. The plugs don't stay on the 9/16th socket and my old spark plug socket was to thick for the throat of the plug wall! I used a very long pair of hemostats to grab the plug and remove it and bought myself a new deep 9/16 socket!
    Just thought any other newbies out there might want to know.
     
    Robert Holt likes this.
  15. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,470
    38,103
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Does the 9/16" socket have the rubber insert? That'll grip the plug securel.

    Sometimes too well, to where the socket will pull off the extension after installing the new plug, stay on the plug. To avoid that wrap a few winds of tape over the junction.
     
    sadhu likes this.
  16. ASRDogman

    ASRDogman Senior Member

    Joined:
    May 29, 2018
    5,836
    3,136
    0
    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    Two
    Snapon uses magnets in there spark plug sockets. Much better than the rubber.
    I used those before, a pain!
    You can also use some hose, fuel or whichever, to put over the top of the plug, then start
    it so you know it's not cross threaded, them pull the hose off. You only need to push it on
    enough to hold it.
     
    sadhu, Robert Holt and Grit like this.
  17. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,470
    38,103
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    I'm ok with the rubber insert; they're commonly available here. Except that when the sockets are brand new they can be too tenacious. Test them: put the socket on an extension, then push in the spark plug, then pull it off, and see what separates from what. If the socket pulls off the extension: wrap the joint with some tape.
     
  18. ASRDogman

    ASRDogman Senior Member

    Joined:
    May 29, 2018
    5,836
    3,136
    0
    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    Two
    If you want to go the cheap way, you could spray them with oil or something so it will hold it
    long enough to get the plug started but then slip off easily.
     
    Robert Holt and Mendel Leisk like this.