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Oil on top of plugs?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jeeper5usa, Jan 4, 2015.

  1. jeeper5usa

    jeeper5usa Junior Member

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    I seem to be getting oil/oil gunk on top of the plug, which eventually causes me misfires. I changed the plugs, but don't really want to be changing the plugs every six months. How can I fix this? Will replacing the $90. a plug spark boot solve this issue? I just don't know how this oil gunk is getting ON TOP of the plug and causing misfires. I thought about putting a ring of silicone on the washer on the spark boot. I'm lost as to what is causing this, Any ideas?
     
    #1 jeeper5usa, Jan 4, 2015
  2. edthefox5

    edthefox5 Senior Member

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    Never heard of gunk On top of the plug under the boot.
    Just heard of rain water Getting through the seal of the reservoir below the windshield where the rain accumulates. The seal on the edge where it
    Prevents overwaterinto the engine compartment as that causes water to drip on the tip of the engine
    And it gets in the plug wells and throws a misfire. There is a TSB
    For that seal.

    Your boot rubber on the cop may just be disentigrating.
     
    #2 edthefox5, Jan 4, 2015
    Last edited: Jan 4, 2015
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Is it possible that when the engine oil was last replaced, that whomever did it was very messy and allowed some oil to flow on the engine valve cover, thus seeping down into the spark plug wells?

    If that is not possible, then you probably need to remove the valve cover, install a new valve cover gasket, and reinstall the valve cover. FIPG needs to be applied at two spots near the front of the valve cover for proper sealing. Consult techinfo.toyota.com to obtain the factory repair manual, for further details.
     
    #3 Patrick Wong, Jan 4, 2015
  4. jeeper5usa

    jeeper5usa Junior Member

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    Ty for the response. I changed the oil myself and was very careful. I thought myself also that it may be valve cover gasket but we had this replaced by private shop last year, I'm thinking maybe they didn't do a good job or they did not seal it very good. But if it's valve cover gasket then wouldn't oil be on the bottom fouling the plug not on the top? Thank you. Ask comments very appreciated.
     
    #4 jeeper5usa, Jan 4, 2015
  5. bisco

    bisco cookie crumbler

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    how many miles on her?
     
    #5 bisco, Jan 4, 2015
  6. edthefox5

    edthefox5 Senior Member

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    Old car.
    How many miles.
     
    #6 edthefox5, Jan 4, 2015
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The spark plugs screw into the cylinder head, not the valve cover. Hence a valve cover oil leak would appear on the plug above the threaded area.

    Are all four spark plugs affected by this issue?

    Given your latest post it sounds like the valve cover gasket is leaking again. What were the circumstances that prompted you to have it changed originally, where was the valve cover leaking, and was the correct Toyota gasket used?

    You might check the tightening torque of the bolts and nuts that secure the valve cover, the spec is 7.4 ft.-lb. Do not exceed that torque, you don't want to strip the cylinder head threads.
     
    #7 Patrick Wong, Jan 4, 2015
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