Cabin airflow direction

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Falcor, Jun 29, 2020.

  1. Falcor

    Falcor New Member

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    I have a 2010 Prius IV and when I went to change the cabin air filter I noticed the cover said “UP” with and arrow pointing up. Well out of curiosity I removed the old filter and stuck a string in there and the flow is definitely downward!

    I’m just trying to figure out which way to install the filter
     
  2. Tideland Prius

    Tideland Prius Moderator of the North
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    Match the UP on the cover with the UP printed on the side of the air filter.

    UP means up this way (like those moving or packing boxes). It doesn’t indicate flow direction.
     
  3. 2012 Prius v wagon 3

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    The UP tells you which way is up (towards the sky, hopefully), regardless of airflow.

    You are right, the air flow direction is downwards.

    If airflow is marked on the filter (i.e., it says "Airflow", not "UP", since those are different things in this case), well you should follow that. So if it is marked "Airflow ^", then you should mount it so the ^ is pointing down, and the "Airflow" is upside down. But if it says UP, ...

    Many air filters are not symmetrical - the air can only properly flow in one direction. For example, they may have a wire mesh providing support from the back side, whereas it would not be able to provide support if it were on the upstream side of the filter element. But these Prius filter appear to be symmetrical, so it probably does not matter which way you put it in. So why would they mark it, if it is symmetrical? Well that would prevent you from possibly removing it and reinstalling it flipped. That would be bad since all the junk that was caught will now be very quickly blown out into the cabin.

    If you want to do it backwards, follow this guy on youtube:


    Confirming it can be confusing even to the brainiacs on youtube. Seriously, this is so common with so many things on youtube. Someone does not really know what they're doing, so what do they do? They go and make an instructional video on how to do it wrong. It is a real skill to be able to watch videos and still get useful info out of it.

    And if you see that video and how dirty the top of the filter is, that clearly confirms flow direction.

    As I suggested above, the filter may be symmetric (it looks like it is), in which case he does not really need to go back and change it, he just needs to be sure not to flip it some time in the future.
     
    #3 2012 Prius v wagon 3, Jun 29, 2020
    Last edited: Jun 29, 2020
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  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Maybe the main issue is to not use it one way, then flip it. Or maybe it does matter. Either way, "up" is unambiguous, or should be.
     
  5. Grit

    Grit Senior Member

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    I requested to have my screen name change and was denied. Hard to believe that OP name is much vulgar than the name I requested for and his name is fine.
     
  6. bisco

    bisco cookie crumbler

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    if it was air flow direction, it would say 'flow' with an arrow
     
  7. mikey_t

    mikey_t Active Member

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    There really should be better curriculum in schools on how to do proper presentations. A while back I was watching a Photoshop tutorial for a specific editing technique and the person, a popular and known photographer, didn't even bother with the second half b/c she liked how the image looked after the first. THAT IS NOW HOW TUTORIALS WORK.
     
  8. ASRDogman

    ASRDogman Senior Member

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    I would say "common sense" would tell you that the side with all the dirt, is where the is coming FROM.....
     
  9. Grit

    Grit Senior Member

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    If air flow was upwards, how would dirt settle onto the under side of the filter with gravity :D

    Disclaimer- this reply may not apply in all situations.
     
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Airflow direction requires waay to much sleuthing; "this side up" is simple as can be.

    The Toyota filters, being for specific case can use the TSU label, aftermarket not so much.

    I might just change the cabin and engine air filters on ours, it's coming up on 10 years this fall. :ROFLMAO:
     
  11. Grit

    Grit Senior Member

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    I told mine I have google now and don’t need it anymore. Common sense finally left me :cool:

    Disclaimer- this reply may not apply in all situations
     
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  12. Falcor

    Falcor New Member

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    The filter I got said “air flow”. I think the “UP” is more of a OEM thing

    Yup he definitely installed it the wrong way. Luckily several people in the comment section called him out

    Since you complained I had to change my name. It was from the movie Stepbrothers.

    When I went to get an oil change they suggested I replace the engine filter. I told them I would do it myself.

    On my receipt it said they suggested the filter be changed and in parentheses it said “very hard to access“. It took me 30 seconds LOL
     
    #12 Falcor, Jul 1, 2020
    Last edited by a moderator: Jul 1, 2020
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  13. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah engine air filter is very easy; just fast-talking "service advisors". They should all be on the B ark.,,
     
  14. Tideland Prius

    Tideland Prius Moderator of the North
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    A young kid called me out once "do you even know how to change the engine air filter?" lol. (Cause I called him out on the Prius' transmission and he wasn't happy I "knew" more than him).
     
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  15. 2012 Prius v wagon 3

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    LOL on the Boats n Ho's. I got the stepbrothers joke, googled, and actually saw they have a full (2 minute) video vs. the shorter part in the movie, as I recall. I was not offended at all. Great movie.

    In fact, "Grit" might remind some people of the movie "True Grit" starring John Wayne, and wow, snowflakes melting everywhere. This is the very definition of microaggression (yes, that's a thing, LOL). I pray that the administrators let Grit change his name to whatever he wants. (and I looked for a "pray" emoji, but see none exists, as it would be sure to offend ... someone :ROFLMAO:)

    On the filter, the OE part manufacturer probably knows exactly what car it's going in, so they know which way is UP, and the installer will probably find it easier to know which way is UP vs. knowing which way the air flows.

    Aftermarket parts may be installable in multiple cars, and if the filter is asymmetric (in addition to the very clear use of a metal supporting mesh on the downstream side, the filter material itself could have different layers within it, making it asymmetrical), they need to indicate airflow, and then the installer needs to know which way the air flows.

    If your filter is dirty enough, the airflow direction should be obvious from that. If the filter is not dirty enough to tell, maybe it does not need replacing. As Bob Dylan said, "you don't need a weatherman to know which way the wind blows."

    I think if a filter does not say either UP or Airflow, but does have an arrow, it probably indicates airflow. If none of those, I'd base it on structure - does it have a wire mesh for support. If none of any of those, it probably does not matter at all, other than to avoid flipping it after having it installed.
     
    #15 2012 Prius v wagon 3, Jul 1, 2020
    Last edited: Jul 1, 2020
  16. Mendel Leisk

    Mendel Leisk Senior Member

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    Toyota could do everyone a favour, ad a flow-direction arrow, say on the cabin filter door. That would kinda condone aftermarket filter usage, which goes against their grain I think. Too, this is the cabin filter, not exactly crucial, lol.
     
  17. Grit

    Grit Senior Member

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    I wasn't complaining :cautious: To be specific, I was whining :LOL: that you get to have a name like that but the admin won't allow me to change my name to something less sexually vulgar than yours and the name I wanted to change to doesn't even offend anyone or any group :LOL:
     
  18. Grit

    Grit Senior Member

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    Haha I laughed out loud about you looking for a pray emoji. I agree, someone will eventually find a way to be offended. As for the name change, I'll just create a new account with new signatures. Total post count isn't a concern of mine either.
     
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