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

Replacing 3rd Gen Spark Plugs

Discussion in 'Gen 3 Prius Technical Discussion' started by R1CH13, Sep 5, 2014.

  1. R1CH13

    R1CH13 Member

    Joined:
    Feb 26, 2013
    54
    25
    9
    Location:
    Michigan
    Vehicle:
    2011 Prius
    Model:
    Two
    So I work for Toyota in the Internet Sales Department and every salesman keeps telling me that spark plugs last up to 100,000 miles or more. I just run with it since Toyota states that it does but as a Prius owner I find it hard to believe something like this last that long. I replaced my spark plugs at 75,000 miles and you tell me if the sparks plugs are still good or does it need to be replaced? I replaced them from OEM Denso to NGK as I prefer NGK. New spark plug on left and old on right (75,000 miles) diff.jpg ngk.JPG
     
  2. R1CH13

    R1CH13 Member

    Joined:
    Feb 26, 2013
    54
    25
    9
    Location:
    Michigan
    Vehicle:
    2011 Prius
    Model:
    Two
    Also here is somewhat of a step by step on how I took apart the 3rd Gen Prius. Note: You must find a deep socket that fits this spark plug as it was a pain finding some around my area. No auto or hardware store had them in stock.
     

    Attached Files:

    • 1.jpg
      1.jpg
      File size:
      43.7 KB
      Views:
      2,311
    • 2.JPG
      2.JPG
      File size:
      79.2 KB
      Views:
      2,239
    • 3.JPG
      3.JPG
      File size:
      61.7 KB
      Views:
      2,222
    • 4.JPG
      4.JPG
      File size:
      58.4 KB
      Views:
      2,149
    • 5.JPG
      5.JPG
      File size:
      67.4 KB
      Views:
      2,100
    • 6.JPG
      6.JPG
      File size:
      47.1 KB
      Views:
      2,126
    • 7.JPG
      7.JPG
      File size:
      78.7 KB
      Views:
      2,175
    • 8.JPG
      8.JPG
      File size:
      68.2 KB
      Views:
      2,124
    • 9.JPG
      9.JPG
      File size:
      116 KB
      Views:
      2,127
    • 10.JPG
      10.JPG
      File size:
      105.3 KB
      Views:
      2,031
    • 11.JPG
      11.JPG
      File size:
      106.8 KB
      Views:
      2,084
    • 12.JPG
      12.JPG
      File size:
      111.4 KB
      Views:
      2,090
    • 13.JPG
      13.JPG
      File size:
      67.4 KB
      Views:
      2,088
    • 14.JPG
      14.JPG
      File size:
      116.9 KB
      Views:
      2,212
    • 15.JPG
      15.JPG
      File size:
      96.8 KB
      Views:
      2,085
    • 16.JPG
      16.JPG
      File size:
      99.6 KB
      Views:
      2,206
    • 17.JPG
      17.JPG
      File size:
      120.5 KB
      Views:
      2,256
    • 18.JPG
      18.JPG
      File size:
      125.2 KB
      Views:
      2,289
    Cyon Kim, kc410 and spiderman like this.
  3. Mike500

    Mike500 Senior Member

    Joined:
    Mar 1, 2012
    2,593
    763
    0
    Vehicle:
    2012 Prius v wagon
    Model:
    Two
  4. Munpot42

    Munpot42 Senior Member

    Joined:
    Mar 12, 2012
    1,391
    543
    0
    Location:
    Santa Monica, Ca. 90405
    Vehicle:
    Other Hybrid
    Let us know if you show an increase in gas mileage with the new plugs.
     
    Jon Senum likes this.
  5. HaroldW

    HaroldW Active Member

    Joined:
    Mar 17, 2012
    716
    95
    0
    Location:
    Grand Forks BC Canada
    Vehicle:
    2014 Prius
    Model:
    Three
    What a pain to change 4 plugs. H
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,737
    38,260
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    That's a 9/16" socket. It's a semi rare but available spark plug socket. Make sure it has the rubber insert to grip the plug.

    Nutzaboutbolts has a youtube video on 3rd gen spark plug access. Insane amount of disassembly required, shame on Toyota.

     
    ednorton and spiderman like this.
  7. R1CH13

    R1CH13 Member

    Joined:
    Feb 26, 2013
    54
    25
    9
    Location:
    Michigan
    Vehicle:
    2011 Prius
    Model:
    Two
    I didn't have the rubber inside the deep socket :( but I did improvise. I used one of those magnetic long stick things and gently set it down. It did the trick but I'm gonna order one of those sockets Rude person's posted. I will test out my mpg tomorrow as I drive 60 miles a day. With the old spark plugs I was averaging 57-60 mpg going 60-65mph.
     
  8. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,801
    48,999
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    i think the old plugs look fine, many here have pulled them at 100k and found them in excellent condition and perfectly gapped. i would wait until the recommended 120k unless i was having related issues.
     
    Feri likes this.
  9. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,737
    38,260
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    If you've got some sort of discount automotive nearby you might luck out.

    This is a Canadian retailer where I found one:
    Princess Auto
     
  10. DaneH5

    DaneH5 Member

    Joined:
    Aug 12, 2014
    464
    60
    0
    Location:
    Pinellas, Florida
    Vehicle:
    2014 Prius
    Model:
    Three
    Any MPG update info yet?
     
  11. gliderman

    gliderman Active Member

    Joined:
    Aug 2, 2011
    751
    223
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    IV
    Didnt someone do a video on this a couple of years ago? I know I saw one, just not sure where. Maybe someone could find it and link it to this thread.
     
  12. qdllc

    qdllc Senior Member

    Joined:
    Aug 25, 2013
    1,358
    396
    0
    Vehicle:
    2013 Prius
    Model:
    Two
    The newer platinum and iridium spark plugs have the virtue of "self cleaning" when hot, and that really does a lot to extend their service life...presuming you don't have a serious carbon fouling problem.

    I went to those years ago on my motorcycle because a fouled plug will mandate replacing plugs, and in the middle of a ride or trip can be a disaster. Platinum or iridium plugs...just get the motor running for a few minutes and the heat will clean the plug once you stop whatever caused the fouling in the first place.
     
  13. David Beale

    David Beale Senior Member

    Joined:
    Jul 24, 2006
    5,963
    1,981
    0
    Location:
    Edmonton Alberta
    Vehicle:
    2012 Prius
    Unless the spark plug actually has a -failure- (seal, broken insulator, etc) what wears is the tip. If you look at the picture the old plug has almost as much tip as the new one. I think it looks just fine. Just a little dirty.

    Yes, they are a pain to change. There are -some- cars that are worse, but yes, it's a shame the designers couldn't make it easier. Perhaps they don't because they know the plugs last so long. ;)
     
    SageBrush and HaroldW like this.
  14. Mike500

    Mike500 Senior Member

    Joined:
    Mar 1, 2012
    2,593
    763
    0
    Vehicle:
    2012 Prius v wagon
    Model:
    Two
    I remember the old days of leaded gas, when spark plugs acquired a light brown coating at 1,000 to 1,500 miles.
     
    Friend of Bill W. likes this.
  15. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,737
    38,260
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Look up the page. ;)

    The frustration with the OP's picture of the old and new spark plugs: it's out of focus. When you view the original size, larger image, it just gets worse.

    He doesn't mention any gap measurement. It's really hard to tell from the pic, but it kinda looks like the gap on the old one has opened up some.
     
    #15 Mendel Leisk, Sep 6, 2014
    Last edited: Sep 6, 2014
    HaroldW likes this.
  16. R1CH13

    R1CH13 Member

    Joined:
    Feb 26, 2013
    54
    25
    9
    Location:
    Michigan
    Vehicle:
    2011 Prius
    Model:
    Two
    The gas mileage did not change but I did feel a difference in transition from electric to gas motor and vice versa. The transmission shifted a little smoother than before and the acceleration might have changed? It drove just like the day I bought it but then again the changes I'm speaking of could be in head.
     
  17. R1CH13

    R1CH13 Member

    Joined:
    Feb 26, 2013
    54
    25
    9
    Location:
    Michigan
    Vehicle:
    2011 Prius
    Model:
    Two
    .
     
    #17 R1CH13, Sep 6, 2014
    Last edited: Sep 6, 2014
  18. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,737
    38,260
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
  19. wjtracy

    wjtracy Senior Member

    Joined:
    Sep 19, 2006
    11,314
    3,588
    1
    Location:
    Northern VA (NoVA)
    Vehicle:
    Other Hybrid
    Model:
    N/A
    ....keep in mind the Iridium is a very special substance very expensive very rare more expensive than platinum, one wonders how it makes sense to waste this rare element on spark plugs. I'm keeping my old ones. I did not replace my Gen2 plugs until about 135k miles. Picture below you can sort of see how the plug metal is eroded but the Iridium is as good as new holding the gap. I saw no poor MPG with the older plugs. One way to think of it, it is sort of a waste of rare Iridium to replace too early.
    plug_photo.JPG
     
    #19 wjtracy, Sep 6, 2014
    Last edited: Sep 6, 2014
    Jon Senum likes this.
  20. milkman44

    milkman44 Active Member

    Joined:
    Oct 16, 2011
    591
    386
    0
    Location:
    Ky
    Vehicle:
    2010 Prius
    Model:
    II
    But, but, but, oil changes at 3K or 5K is way better than the 10K recommended:rolleyes:. then changing 120K plugs at 60K is way better too then, right?:rolleyes::rolleyes:
     
    Jon Senum likes this.