Cabin airflow direction

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.

 

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.

 

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.

 

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

 

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.

 

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

 

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

Disclaimer- this reply may not apply in all situations.

 

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.

 

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

Disclaimer- this reply may not apply in all situations

 

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

 

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 )

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.

 

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.

 

I wasn't complaining To be specific, I was whining 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

 

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.