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Brown fuzzy deposit on old spark plugs

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Sterlingarcher6969, Jun 5, 2022.

  1. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    Just curious as to what this means. I just changed these out as part of my 150k service From what I've seen online is that it's oil deposits or fuel additives.

    Note: I only ever use Costco gasoline.

    When I bought the car at 128k it consumed a quart of oil every 4k or so but after 140k it doesn't consume a drop (used the techron fuel additive like 3 times over a couple months)

    PXL_20220605_203022438.MP.jpg the plug from cylinder 4 seemed to have the most buildup
     

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    #1 Sterlingarcher6969, Jun 5, 2022
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    What's the order of plugs in the pic?

    Also, in the pic that's not embedded in text, that's gotta be a new plug, on the right? Exact same type of plug?
     
    #2 Mendel Leisk, Jun 6, 2022
  3. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    Yeah that imbed pic was a comparison of old (left) and new (right) both are the same brand

    Yeah I didn't put them in order in the pic
    Far left is cylinder 2
    Far right is cylinder 3
    Middle left is cylinder 4
    Middle right is cylinder 1
     
    #3 Sterlingarcher6969, Jun 6, 2022
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  4. PriusII&C

    PriusII&C Active Member

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    Don't know what the deposit is on the spark plugs. But interested in knowing that fuel additives reversed an oil burning issue. Care to elaborate how this works?
     
    #4 PriusII&C, Jun 7, 2022
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  5. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    I used the techron additive, you can get it at AutoZone It costs like 10$ I figured I may as well try it (use the small one says like good for 12 gallons) pour the whole thing in after you fill up and run it down to one bar and repeat a week later.

    Did this 3 times and it stopped burning oil.

    I am willing to bet it was one of those instances where that stuff works on 1% of oil burning engines.

    Worth a shot for 10 bucks.
     
    #5 Sterlingarcher6969, Jun 7, 2022
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  6. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Those are ash deposits. Extremely normal to find, particularly with the additives in California fuel.

    When the deposits get super thick it'll cause problems, but that's a very mild case in your picture.

    No corrective action indicated.
     
    #6 Leadfoot J. McCoalroller, Jun 7, 2022
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