Intake or exhaust valve stem cap!

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Notn2bars, Aug 2, 2025 at 5:45 PM.

  1. Notn2bars

    Notn2bars New Member

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    We have a 2012 Prius. Recently did a bunch of work on our Prius. Long story short, had to take it to the dealer because we couldn't get in running correctly.They discovered that one of the valve stem caps was missing and could not locate it. All of them were installed and everything was torqued to specs when the I replaced the head gasket. Sooooooo, where could the cap have vanished? Could it have landed on top of one of the pistons? Is there an oil passage from the top of the head to the oil pan large enough for the cap to pass through? Any other thoughts? Your help is sincerely sought and appreciated. Will be going to the dealer on Monday to see what the options will be.

    God Bless, Ed Jones
     
    #1 Notn2bars, Aug 2, 2025 at 5:45 PM
  2. ChapmanF

    ChapmanF Senior Member

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    yikes
     
    #2 ChapmanF, Aug 2, 2025 at 9:22 PM
  3. rjparker

    rjparker Tu Humilde Sirviente

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    It was left out during the hg job or it was loose and fell somewhere in the engine bay when the dealer tech opened it up. Either way it was not installed properly.

    It has happened before.
     
    #3 rjparker, Aug 2, 2025 at 10:56 PM
  4. NutzAboutBolts

    NutzAboutBolts Senior Member

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    Those caps aren’t easily removed by fluids going over it… you have to physically pull it off of the valve stems to remove it from the top. Whoever did the work removed it and forgot to put it back, I would blame the technician who worked on it last when they did your head gasket.
     
    #4 NutzAboutBolts, Aug 3, 2025 at 1:42 AM
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