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Air Oil Separator

Discussion in 'Gen 4 Prius Main Forum' started by jteran5, Jan 31, 2021.

  1. jteran5

    jteran5 Active Member

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    Has anyone installed an air oil separator on their car? Would rather run an AOS than a catch can. I have no experience with these systems at all and there are no shops around me that would be willing go attempt this unless there was a complete kit.

    I'm trying to specifically run the Radium AOS here :


    Universal Air Oil Separator-Return (AOS-R)
    UniversalAOS3.jpeg

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    Mendel Leisk likes this.
  2. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    I’m not sure there’s a difference, between oil catch can and air-oil separator. I’m using Moroso 85474, which is described as the latter.

    Moroso SEPARATOR, AIR-OIL, CATCH CAN, LARGE BODY, UNIVERSAL

    (The manufacturer’s description in above uses both terms, oil catch can and air-oil separator.)

    Of note: the two halves of the body have a fragile o-ring; it should be inspected and have a sparing amount of anti-seize compound applied, whenever the can is opened, and/or replaced if damaged. Fortunately it’s a readily available size (through local automotive parts stores); I can post info if you’re interested.

    Here’s a third gen thread that’s still relevant for fourth gen I think:

    Oil Catch Can, Eliminate that knock! | PriusChat

    I’d say the preponderance of work will be finding a suitable/practical mounting location, routing the hoses. Consider how you’re going to access it, assuming regular draining is required. My own case, I opted to mount below intake manifold, connected with a custom bracket to the front cross beam. I access primarily from below, while doing oil changes.
     
    #2 Mendel Leisk, Jan 31, 2021
    Last edited: Jan 31, 2021
  3. Raytheeagle

    Raytheeagle Senior Member

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    That setup requires a drain line to return the oil :cool:.

    Here's the oil catch can setup I installed on our 2019 Prime:):

    What did you do to your Prime today?

    Any reason you are against an oil catch can:whistle:?

    Good luck and keep us posted(y).
     
  4. jteran5

    jteran5 Active Member

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    AOS drain the captured oil back into the oil pan. Also, these have coolant lines running through them. There is a tendency for the captured blow-by (in either a catch-can or AOS) to have a waxy consistency when it cools off. Over time, this can lead to a quicker build-up in the can which can also lead to blocking off the ports that connect to the crank-case. For that reason, most Air-Oil Separators are designed to run coolant through them to melt these deposits to keep the contents draining back to the sump, and to prevent clogging.

    Nothing to empty and the car will have a more consistent oil level

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  5. Raytheeagle

    Raytheeagle Senior Member

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    Know that the catch can collects more than just oil ;).

    I'm one that doesn't mind purging it out as the can I have had a drain for ease of draining:).

    If you are going to do what the manufacturer recommends (what you state above), your engine bay will look a lot different :cool:.

    Good luck(y).