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Spark plug change on the Gen 3

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Phil W, Apr 25, 2015.

  1. Phil W

    Phil W Junior Member

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    I plucked up the courage to change the plugs myself, I need not have worried the job was easy in spite of the extra work involved to remove the wiper mechanism etc. I thought I would share the experience in case others want to do the same.

    Firstly watch the NutzAboutBolts vid on YouTube it is very informative.
    It took me about 2 hours, but I was working slowly and was cleaning the engine bay at the same time.
    If you have ever changed spark plugs and have used a wrench before you will be fine.
    You do need the extended socket, I suggest a magnetic one to keep the plugs in place.
    I put dielectric grease on the end of the plug as per the vid. However the old plugs were dry ( factory fitted) so I am not sure it's absolutely necessary, so I only put a smear on.
    I did not put anti locking grease on as I understand it is not necessary for new plugs only if you are refitting.
    I did not use a torque wrench but followed Denso's instruction to hand tighten and then tighten 1/4 to 1/2 a turn.
    The old plugs (67k miles) were dirty and the ceramic was brown from the heat. I will try and upload photos.
    The metal tray under the windscreen which has to be removed had blocked drain holes. I could see 'tide marks' along the whole tray, showing I had about an inch of standing water when it rains. It was worth changing the plugs just to clear this, in my opinion.
     
    #1 Phil W, Apr 25, 2015
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Have you got experience changing plugs on older cars. Used to be step one of changing plugs was...: changing the plugs, lol.

    With the Prius you have to pull an insane amount off for access. Our previous Civic Hybrid was similar, though not as bad: the windshield lower cowl had to come out, but at least the wipers and motors stayed in place.
     
    #2 Mendel Leisk, Apr 25, 2015
  3. bisco

    bisco cookie crumbler

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    so weird this thread comes at the time of the other one. you were smart to follow denso's tightening instructions.
     
    #3 bisco, Apr 25, 2015
  4. Phil W

    Phil W Junior Member

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    Yes I remember the days when you could just pop the lead off the plug and unscrew!
    Other thing to watch out for when buying the plugs online is they seem to be sold individually. I thought £15 for a set of plugs felt reasonable (me thinking I used to pay £5 for the set). Oh no how wrong was I, they are £15 each! At least they last longer....
    image.jpg image.jpg image.jpg
     
    #4 Phil W, Apr 25, 2015
  5. zander

    zander Junior Member

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    If possible to get the spark plug number .
     
    #5 zander, Apr 30, 2015
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    In Owners Manual, page 562, says:

    DENSO SC20HR11
    (gap 0.043 in., 1.1 mm)

    They should come pre-gapped, and you likely should just verify, don't attempt to adjust.
     
    #6 Mendel Leisk, Apr 30, 2015
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    A counter example is the 1997 Ford Explorer AWD with 5.0L V8 that I owned prior to the HiHy.

    Step 1 is to raise up the front of the SUV, support with jack stands, and remove the front tires, for access to the spark plugs via the wheel wells.
    Step 2 is to attempt to pull off the high voltage spark plug wires only to find that the rubber caps have melded to the spark plugs, so Step 3 is to buy new spark plug wires.
    Then, an intermediate step during the process is to scrape off an inch of skin on my arm as it rubbed against the steel fender opening. Need to wear a long-sleeved shirt...
     
    #7 Patrick Wong, Apr 30, 2015
    bisco and Mendel Leisk like this.
  8. Den49

    Den49 Member

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    Phil W - Thanks for posting the above pictures of your 67K spark plugs. Looks like they were still good. What you are calling dirty and brown is actually normal and indicates the engine is operating within specifications without any oil or overheating issues.
     
    #8 Den49, May 1, 2015
  9. bisco

    bisco cookie crumbler

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    wasn't there a car that had to have the engine lifted out to get to the spark plugs?
     
    #9 bisco, May 1, 2015
  10. CR94

    CR94 Senior Member

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    Yes, the circa 1976 Chevrolet Monza with a V8 shoehorned into a space designed for the aborted GM rotary. The engine had to be lifted a couple of inches, not totally removed. Or you could drill a hole in the inner fender for access.
     
    #10 CR94, May 15, 2015
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