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If my Prius isn't burning oil will there be oil in the intake manifold?

Discussion in 'Gen 3 Prius Main Forum' started by bootsncats24, Jul 13, 2022.

  1. bootsncats24

    bootsncats24 Junior Member

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    Planning on taking apart my Prius this weekend to clean out the egr system and from the videos I've seen and the forum post there is always some oil in the intake manifold. Since my car isn't burning oil is there a chance of oil in the manifold or just carbon build up?
     
    #1 bootsncats24, Jul 13, 2022
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  2. CR94

    CR94 Senior Member

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    Yes.
    I predict you'll see oil that looks relatively clean near the throttle body, and oily black mess farther downstream.
     
    #2 CR94, Jul 13, 2022
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  3. Georgina Rudkus

    Georgina Rudkus Senior Member

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    Yep.
     
    #3 Georgina Rudkus, Jul 13, 2022
  4. bootsncats24

    bootsncats24 Junior Member

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    Thanks guys.
     
    #4 bootsncats24, Jul 13, 2022
  5. xliderider

    xliderider Senior Member

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    What year is it? How many miles on the odometer?

    As stated, there's always a pool of oil in the intake manifold, under the throttle body.

    While you're in there, it's a good time to install an oil catch can. That will help with some of the oil getting into the intake manifold, which burns in your combustion chambers and causes carbon fouling, which can seize your oil rings, and lead to oil burning.

    Posted via the PriusChat mobile app.
     
    #5 xliderider, Jul 14, 2022
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  6. rjparker

    rjparker Tu Humilde Sirviente

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    The low tension piston rings combined with a low mounted pcv allows the intake manifold to act as a catch can. Even an aftermarket catch can will not totally eliminate this design flaw, one of many in gen3s.
     
    #6 rjparker, Jul 15, 2022
  7. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    The intake manifold will have a pool of oil at the bottom, supplied by the PCV system.

    The EGR components, and the EGR passages through the intake manifold, will have carbon build-up.

    I'd second the question asked above: what's the miles?

    You might want to do the intake manifold one weekend, the main EGR system another. And an Oil Catch Can yet another. Simply because each can get involved. In particular the OCC. I would leave that to last, but don't procrastinate.

    More info in my signature.
     
    #7 Mendel Leisk, Jul 15, 2022
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  8. mikey_t

    mikey_t Active Member

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    It's been mentioned in other threads that 2015 models with the new pistons and rings don't suffer from clogged EGRs, but if the PCV is still also expelling some oil do you think the issue is just being kicked down a longer road?
     
    #8 mikey_t, Jul 15, 2022
  9. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    I’m sceptical of that.
     
    #9 Mendel Leisk, Jul 15, 2022
  10. bootsncats24

    bootsncats24 Junior Member

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    2014 with 105k miles. Cleaned out the intake manifold and the egr pipe. Soaked both of them in degreaser over night and they looked good as new. Will probably wait to do the egr cooler. EGR pipe barely had any carbon on it so I’m hoping the egr cooler is the same. Also changed the PVC valve since the intake manifold was out along with the spark plugs.
     
    #10 bootsncats24, Jul 16, 2022
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