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Can you tell what's wrong with my car by spark plugs?

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  • 12-02-2016 9:26pm
    #1
    B00056718
    Registered Users Posts: 305 ✭✭


    Hi.

    Serviced my car today and when changing the plugs, I really didn't the look of the old ones. They are really badly soiled.

    The car is consuming some oil (still within manufacturers specs), but I would expect the plugs to be black when there's excessive oil burning happening.

    The plugs are white. Almost like a limescale. Not a drop of coolant has been lost in last year and a half.

    The car in question is 07 Lexus GS300. 214k km. Was used for longish runs every day until recently. Even now it gets to full operating temp every day and gets regular spins on the motorway.

    All 6 plugs are the same.

    Please see the pics attached.


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    #2
    Atlantic Dawn
    Registered Users Posts: 81,705 ✭✭✭✭Atlantic Dawn
    M


    How long in miles/km are they in the car? Are they irridium or standard plugs?


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    #3
    B00056718
    Registered Users Posts: 305 ✭✭B00056718


    Atlantic Dawn wrote: »
    How long in miles/km are they in the car? Are they irridium or standard plugs?

    They have around 40k km behind them and they are OEM Denso Irridium. Done by main dealer.


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    #4
    kona
    Registered Users Posts: 7,525 ✭✭✭kona


    Looks like deposits from using poor fuel or burning stuf it's not ment to burn.


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    #5
    B00056718
    Registered Users Posts: 305 ✭✭B00056718


    kona wrote: »
    Looks like deposits from using poor fuel or burning stuf it's not ment to burn.

    Never used any additives. Mainly fill up in Maxol or Texaco. Sometimes in Topaz or Applegreen but very seldom.

    Also. Sometimes under load, I can hear the engine pinking when I open my window but I read that on some cars it's ok. Especially in hot weather. Still. I don't like it.


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    #6
    Atlantic Dawn
    Registered Users Posts: 81,705 ✭✭✭✭Atlantic Dawn
    M


    B00056718 wrote: »
    They have around 40k km behind them and they are OEM Denso Irridium. Done by main dealer.

    Is there a chance the dealer never changed them?


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    #7
    B00056718
    Registered Users Posts: 305 ✭✭B00056718


    Atlantic Dawn wrote: »
    Is there a chance the dealer never changed them?

    I was thinking the same. The tips of the centre electrodes seem to be gone. Can't see it happening in 40k miles. It still doesn't explain the limescale stuff on them.


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    #8
    kona
    Registered Users Posts: 7,525 ✭✭✭kona


    B00056718 wrote: »
    Never used any additives. Mainly fill up in Maxol or Texaco. Sometimes in Topaz or Applegreen but very seldom.

    Also. Sometimes under load, I can hear the engine pinking when I open my window but I read that on some cars it's ok. Especially in hot weather. Still. I don't like it.

    Detonation is a sign of crap fuel, but tbh nobody other than a lab could tell you exactley what is up with those deposits.


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    #9
    Voodoomelon
    Registered Users Posts: 9,662 ✭✭✭Voodoomelon


    A lot of these charts show the same thing, but only generalised causes.

    Plugchopku4.jpg

    check_spark_plug_condition.jpg

    spark_plugs_diagnosis.jpg


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    #10
    Stoolbend
    Registered Users Posts: 1,285 ✭✭✭Stoolbend


    That looks like it's from burning oil.

    Replace them with standard plugs and just change them more often.
    There's not much point putting in plugs that'll do 60k miles if they're just getting gunked up like that.


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    #11
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Signs of oil, and/or they might just have never been changed.


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    #12
    mickdw
    Registered Users Posts: 23,296 ✭✭✭✭mickdw


    I've never seen wear like that on iridium plugs after that number of miles.
    Either they were not the right plugs or they were not changed imo.
    With the kind of gap present there you will have issues anyway so new plugs might be a full cure.


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    #13
    Renegade Mechanic
    Registered Users Posts: 7,934 ✭✭✭Renegade Mechanic


    That's oil burning. Not a lot, I wouldn't worry about the engine unless you actually see blue smoke..
    Couple of reasons (not accusations)

    1: Going too long on cheap oil. The 30,000 km service interval is a lie. Especially in diesel, less so on petrol. By all means have the service intervals ever 30, but change the oil itself every 15..

    2: Burning petrol retrieved from a diesel car. If you work in a garage, you will remove petrol from customers diesel cars almost once a fortnight. A full tank of "destroyed" fuel - that still lights at the sniff of a spark - that would otherwise cost 100 quid, is a pretty tempting thing.... The diesel is an oil and will present you with those plugs come service time. Trust me :o

    3: Fuel additives can do this, though you've said you haven't used them.

    4: You got charged for a set of plugs that didn't make it into your car..


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    #14
    Atlantic Dawn
    Registered Users Posts: 81,705 ✭✭✭✭Atlantic Dawn
    M


    Would be interesting to look at your new plugs after 3 months and again at 6 to see what they look like, if there's an issue it should start to cause similar damage on the new plugs too.


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    #15
    enumbers
    Registered Users Posts: 552 ✭✭✭enumbers


    I've not seen a set of iridium plugs look like that after even 160k (highest millage ive seen on a set in a civic) either they weren't changed when they said they were or you've got running issues. keep an eye on the new ones is the only way you'll tell


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    #16
    B00056718
    Registered Users Posts: 305 ✭✭B00056718


    A quick update.

    After installing brand new Iridium plugs, it was giving a random misfire.

    Pulled all of the covers off to check if I left anything disconnected but nothing obvious. Was the first day off the fags so a little anxious. Went out on an open road and revved the car out to the limiter. Got some black smoke behind and the car is running grand for now.

    Regarding 30000km service - i would never ever run any car for 30000km without oil change. Lexus gets Mobil 5w30 every 7000km.

    I'll check the plugs after couple of months to see whats happening inside.

    Thanks for the replies.


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