Prius Cabin Airflow Filter Direction

Discussion in 'Gen 4 Prius Main Forum' started by rspiet, Jul 8, 2020.

  1. rspiet

    rspiet Junior Member

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    Hello, I bought an after market cabin air filter for my 2016 Toyota Prius 4 from Amazon. There is an arrow on the filter for direction of airflow. Is the airflow up or down?

    Should the arrow be pointing up or pointing down? I no longer have the O.E.M filter, and I don't think it even had an arrow.

    Thanks for you answer.
     
  2. Striker325

    Striker325 Junior Member

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    Check your previous cabin filter. The filter that is in your Prius should also have an arrow

    ONEPLUS A5010 ?
     
  3. jerrymildred

    jerrymildred Senior Member

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    From page 302 of the 2006 owner's manual, which should be the same as all Gen 2 filters:
    Screen Shot 2020-07-08 at 4.11.58 PM.png
     
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  4. alanclarkeau

    alanclarkeau Senior Member

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    He's talking about a Gen 4 - his profile is wrong (or he's got 2 PRIUS').

    But the Gen 4 in Australia has it in the Owner's Manual - probably in the USA one too:

    upload_2020-7-9_11-26-39.png
     
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  5. Georgios

    Georgios Member

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    Some filters don't matter which way the the air flows even if they have Arrow. They are just a mesh element. It matters on higher-end filters that have the charcoal position on one side or like the newest generation of antibacterial green filters on some manufacturers
     
  6. alanclarkeau

    alanclarkeau Senior Member

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    For GEN 4 - the Owner's Manual specifies that it go in a particular way.
     
  7. jerrymildred

    jerrymildred Senior Member

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    Oops, he did say 2016. I missed that. Good catch. 2016 is almost certainly the same as the Prime and here it is in my manual.

    Screen Shot 2020-07-09 at 8.02.39 AM.png
     
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  8. rspiet

    rspiet Junior Member

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    Sorry, I do indeed have a 2016 Prius 4 Touring. I am not sure how to update this on this site. I do not have the filter case, the replacement filter did not come with one. I hope I didn't throw out a necessary part. The new filter just has an airflow indicator. That is why I wanted to know the direction of air flow.
     
  9. Elektroingenieur

    Elektroingenieur Senior Member

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    The case is needed for proper airflow and should have come with the car. If it’s missing, you can buy one as a service part, 88899-47090 or 88899-0R010; see catalog Figure 87-14, Heating & Air Conditioning - Cooler Unit.
     
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  10. rspiet

    rspiet Junior Member

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    Thank you. I threw that out thinking I didn't need it. So much for DIY maintenance.
     
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  11. Mendel Leisk

    Mendel Leisk Senior Member

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    Assuming it's the same as 3rd gen, I believe air flow direction is downwards.
     
  12. rspiet

    rspiet Junior Member

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    Thank you. That is the answer to my original question. Have a great day.
     
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  13. bisco

    bisco cookie crumbler

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    11 posts for a simple answer to a simple question (n)
     
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  14. Georgios

    Georgios Member

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    Yes, True, BUT if its OEM or good quality one. Some times i have had amazon/ebay non branded filter that clearhy havo no arrow or its on the wrong side of the charcoal. The important thing is to see as jerrymildred said is the tray arrow for airflow direction
     
  15. ChapmanF

    ChapmanF Senior Member

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    Some filters will have an arrow that says "FLOW", some filters will have an arrow that says "UP".

    In a Prius, that means those filters should have their arrows point opposite ways.

    Unless somebody tells me Gen 4 is different, all Prii have had downward airflow through the filter.

    There's no law that requires it, but it's also kind of unsurprising, since the air comes in at the cowl ahead of the windshield, and from where the heater is, that's, you know, up.
     
  16. bisco

    bisco cookie crumbler

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    same with my central vac. the trouble with upward air flow is gravity
     
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  17. Vman455

    Vman455 Active Member

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    According to the textbook in front of me (Frank White, Fluid Mechanics 8th ed.), the effect of gravity on incompressible flow (e.g. airflow below ~Mach 0.3) can be treated as negligible. You can see a real-world example of this on just about every Shopvac ever, where the motor is mounted on top of the basin and pulls air up and out.

    The two air filters in the Prius are, I suspect, positioned as they are to make dealing with debris easier (which is very much affected by gravity). In the cabin, downward airflow will collect debris on top of the filter, where it can be easily disposed of by taking the filter out since the rest of the ducting is inaccessible. In the engine intake, air is pulled up and through the filter; debris will collect at the bottom of the plastic housing which can be taken out and emptied if necessary and won't affect airflow through the filter. My guess, anyway.
     
  18. Mendel Leisk

    Mendel Leisk Senior Member

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    Engine air filter flow is upward, the opposite.
     
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  19. Vman455

    Vman455 Active Member

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    "In the engine intake, air is pulled up and through the filter...."
     
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  20. Mendel Leisk

    Mendel Leisk Senior Member

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    should have read more carefully. :oops:
     
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