Cabin Air filter

I am confused about the air flow direction for the cabin air filter in the back of the glove box. Does the air flow from top to bottom or bottom to top? Thanks.

 

I think top to bottom?

 

Fire up the truck and see

 

The fan is below the filter and it pulls air down through the filter, so top to bottom is correct

 

I think it's bottom to top. The blower motor is on the bottom under the filter and would blow air up to the vents.

 

https://youtu.be/tZivyeFN2Ag

You can see at 1:33 in that debris is on the top coming from the cowl openings, airflow should be top to bottom. Blower is pulling air down

 

The filters I have replaced have arrows that show air flow.

 

Top to bottom. Outside air is drawn in from the cowl.

 

The problem with going by the arrows is that the factory filter's arrow shows which direction is up (filter orientation), while the replacement filters' arrow shows the direction of air flow, which are opposite, since air flow is from top to bottom. But in the grand scheme of things, it probably doesn't matter all that much how it's oriented, except to those CDO* folks like myself.

*CDO - it's like OCD, but in alphabetical order, as it should be.

 

I change the cabin filter at least once a year and get them very cheap thru Rockauto.........but almost EVERY TIME I do replace the filter a dried up leaf or two will fall into the the squirrel fan and make a lot of noise if not removed. So I now use a small mirror to see inside the squirrel fan and pick out the dried up leaf before installing a new filter. Just a small tip for your future new cabin filter installation.

 

https://assets.sia.toyota.com/publications/en/om-s/OM34477U/pdf/OM34477U.pdf pg. 400 says the arrow on filter is up...just like the cover indicates. The importance is that the proper filter media must be exposed to the incoming air from the outside vent in the firewall... the arrow points to the side that has to be on top.

 

Buying OEM definitely takes the guess work out of it for me. My OCD self spent way too much time overthinking things when I went aftermarket, I couldn’t tell which was the right way. OEM has an arrow and says up…worth the extra $ for me at least.

 

clear as mud fellas thanks for getting that figured out.

 

the air flows from top to bottom.
Like this,...

And the fan always sucks air through the filter, never trying to push the air through the filter. Just like any air filtration unit, forced air furnace, etc.
So if the fan is below the filter, it's sucking air down, through the filter.
Reference the pic above for flow direction.

 

Love it!!!

 

I always wanted to be the guy that writes the directions on stuff.
I think I got what it takes.

 

I think I can clear up some confusion if anyone is still stuck on this…the cover that seals the filter in has an arrow ^ and says up on it, which makes sense as the tabs that hold it in place are not centered top to bottom(so it’s telling us which end of it is up and has nothing to do with the filter placement). The outer cover for the cover that seals the filter(the back of the glove box ‘not-so-secret’ hiding place cover has not one but two arrows pointing up and says “slide up and remove”…yet again these arrows have nothing to do with the fact that the air flows through the ductwork from top to bottom so any “air flow” directional arrow on an aftermarket filter(probably a bit cheaper that the OEM that likely has arrows on all four edges pointing in alternating directions that say “up”, “the other way”, “over there”, and the last one is simply ‘the finger’ (the one that feeds regurgitated worms to its little fingers), pointing up naturally, and says ‘you White, I Wong’. I have to believe that there are many automobile engineering meetings of the minds where there is lots of laughter going on as they come up with new ways to confuse people into paying too much for routine maintenance with proprietary misinformation(for example the valve that has to be held open with a paper clip before starting the Simon says routing to drain and properly replace the ATF on these trucks, I watched 12 videos and only one guy in Australia pointed out the valve, all others were shocked that only 3 quarts drain out), they also have similar meetings at Ford when they’re rolling dice to see where to put hidden metric fasteners and designing proprietary tools! Hope this makes someone laugh…

 

Air flows toward the footwell

 

It is as simple as this:

a. If the filter has an arrow only, the arrow points up. This is NOT telling you that the arrow show "airflow", just the filter's top surface. This usually is the case with dual layer filters, or a filter that has a layer of "activated charcoal" and the rest is just paper. The layer of charcoal should be on top, not at the bottom because the fan would blow charcoal dust into the cabin.

b. Airflow in most automobiles takes place with the intake near the top, not under the automobile. The fan always pulls air into the cab, not the other way around. The fresh air being pulled into the cab goes downward through the air filter and then the fan blades pushes it into the air vents.

c. If you buy a new filter and the words, "AIRFLOW" are stamped on it, plus an arrow pointing down, then install it with the arrow pointing down, because it has nothing to do with which layer of the filter being the top or the bottom, just with the airflow.

https://www.youtube.com/watch?v=tZivyeFN2Ag

 

i believe it is side-to-side

 

Psssst.......its always top to bottom.

 

Wanted to verify airflow was down. After taking the filter out…ya, I guess it’s down lol.

 

Here is another tip. Use a charcoal impregnated cabin air filter for better odor control and the pests don't like it so you won't get any nests in there.

https://www.oreillyauto.com/detail/...814/automotive-truck-2011-toyota-tundra?pos=4

 

Geez, glad none of you guys are design engineers for Space-X.

 

Just shove it in. You got a 50/50 chance of getting it right.

 

TWSS

 

If my experience with USB cables is any indication, that 50/50 chance will be wrong 100% of the time.

 

Holy shite. You too??????????

 

Yep, sometimes I even stop and think to myself...




"They're ALWAYS upside down, so I'm gonna' flip it over first."

 

As per manual instructions found in glove box.