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Oil on coil?

Discussion in '3rd Gen. Tacomas (2016-2023)' started by Trickyrick67, Jan 14, 2025.

  1. Jan 14, 2025 at 7:14 AM
    #1
    Trickyrick67

    Trickyrick67 [OP] New Member

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    Good morning all, New member here reaching out with a question about my ignition coils. During my 240,000 mile service on my 2016 TRD Sport. I noticed some what appears to be burnt oil on one or two of my coils. (Please see pic). This is the worst one. Most of the others just look a little rusty. This one however looks to be a little wet and rusty. I haven’t had any misfire issues or anything. I just noticed this during plug change. This is the 3rd plug change. Am I looking at a gasket change in the near future or could maybe be something else like a PVC valve stopped up with the spark plug not seated or something? Please advise and thanks in advance.

    IMG_9534.jpg
     
  2. Jan 14, 2025 at 9:15 AM
    #2
    TA2016

    TA2016 Well-Known Member

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    Look closely at the coil seal (the black ring on the left side of your picture) and make sure it is not damaged and sealing properly.
     
  3. Jan 14, 2025 at 10:22 AM
    #3
    jmneill

    jmneill Well-Known Member

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    Valve cover gasket / coil tube seal.
    Not sure if the two are integrated on 3rd gen Tacomas, but you'd knock out both anyway.
    My '14 Camry and '14 4Runner are both doing it. I'll get around to it if and when it becomes a problem.

    However, yours seems unusually dirty, rather than just oily. Maybe someone else will chime in.
     
  4. Jan 14, 2025 at 10:37 AM
    #4
    Dm93

    Dm93 Test Don't Guess

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    That looks more like the result of a loose/leaking spark plug.
     
  5. Jan 14, 2025 at 10:44 AM
    #5
    jmneill

    jmneill Well-Known Member

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    Might be, but there should be obvious evidence on the plug itself if that's the case.
    OP didn't mention anything amiss with the plug, however.
     
  6. Jan 14, 2025 at 10:57 AM
    #6
    Dm93

    Dm93 Test Don't Guess

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    Maybe not but that's typically what I see on coils where a plug is loose/leaking, oil from a leaking valve cover pools at the bottom of the tube and leaves a shiny/oily mess on the coil and boot. The coil pictured is brown and crusty which suggests hot combustion gases have been baking it.
     
    jmneill[QUOTED] likes this.
  7. Jan 14, 2025 at 10:58 AM
    #7
    jmneill

    jmneill Well-Known Member

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    I agree, mine are oily, not dirty. Not oily enough to pool, but oily.
    Maybe the OP could post a pic of the plug in question.
     
  8. Jan 15, 2025 at 7:52 AM
    #8
    Trickyrick67

    Trickyrick67 [OP] New Member

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  9. Jan 15, 2025 at 7:53 AM
    #9
    Trickyrick67

    Trickyrick67 [OP] New Member

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    Yeah, not seeing any damage or abnormal wear on the coil seal
     
  10. Jan 15, 2025 at 7:56 AM
    #10
    slater

    slater Well-Known Member

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    lots of not so good guesses....
    if you didnt spill oil into the sparkplug valley area when possibly filling during an oil change, no idea if thats possible...

    Your valve cover gasket is leaking, you have an oring under the valve cover specific to the sparkplug well.....
     
  11. Jan 15, 2025 at 8:03 AM
    #11
    Trickyrick67

    Trickyrick67 [OP] New Member

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    I’m posting this pic with the corresponding plugs with cylinders. Cylinder #6 plug definitely was easier to get out, however all were torqued to spec (23 ft lbs) on my last plug change which was 100k ago. I’m not a mechanic but I’m not seeing any correlation between the plugs and coils. Do you all think I should just replace all the coils?

    IMG_9544.jpg
     
  12. Jan 15, 2025 at 8:07 AM
    #12
    jmneill

    jmneill Well-Known Member

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    No, it isn't..
     
  13. Jan 15, 2025 at 8:22 AM
    #13
    jmneill

    jmneill Well-Known Member

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    It sure looks like loose plug(s)
    If you're thinking of replacing the coils as preventive maintenance, go for it, but they have nothing to do with the problem at hand.
     
  14. Feb 26, 2025 at 10:50 AM
    #14
    deerhntrmike

    deerhntrmike Active Member

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    My coils look like that from the spark plugs coming loose. I’m at 150k and had loose plugs three different times. I heard that they can come loose from detonation. The second time that it happened the engine went into limp mode. Luckily only one mile from home. Fault code showed misfire on one cylinder. Checked all the plugs and found two that were loose. Cleaned up the coils and everything went back to normal. Today I noticed a rough idle. Sure enough three loose plugs. Tightened those up and rough idle went away.
     
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  15. Feb 26, 2025 at 11:57 AM
    #15
    jmneill

    jmneill Well-Known Member

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    If you're having spark plugs routinely backing out, they either weren't properly torqued, or something was terribly wrong with them to begin with, the latter of which I've never seen, nor heard of being seen.
     
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  16. Feb 27, 2025 at 3:46 AM
    #16
    deerhntrmike

    deerhntrmike Active Member

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    Do a search on this site. Loose spark plugs are a common thing. Both factory and aftermarket plugs came loose on my tacoma. I have worked on vehicles/motorcycles/snowmobiles/small engines for over 45 years and have never seen this before my 2018 Tacoma.
     
  17. Feb 27, 2025 at 4:28 AM
    #17
    jmneill

    jmneill Well-Known Member

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    Loose plugs from the factory, all too common.
    Properly torqued plugs backing out, I have not seen.

    Anything's possible, I suppose, but it would be a first in my experience.
    Third gen Tacoma's also seem to have a propensity to eject oil caps as well. If true, another unexplained phenomenon.
     

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