Yesterday I decided to replace the cabin air filter located behind the glovebox. To my surprise I found the filter absolutely chock full of fresh acorns! Some of the filter material separated and I found additional acorns below the filter nicely nestled in the blower motor. I counted and removed 136 acorns in all!! My question is this: Where is the primary intake for the cabin air?? I see no obvious intake point at the firewall or its environs. My thought is to place some kind of screen at the C.E.P. (chipmunk entry point) until winter arrives. I am thinking if a chipmunk is smart enough to find it I should be able to do so as well. Thanks for your input.

Still looking for an answer to my query. Thanks

OK, I don't have an RX but I'll bet the intake to the cabin filter is the same place as in my 00 LS that has it's cabin filter in about the same location as yours.

Look under the hood just forward of your windshield. This diagram shows the intake on your RX in the same place as it is on my LS: http://www.toyodiy.com/parts/p_U_2005_LEXU....html?hl=55879B

Look in the area of the "SEAL, COWL VENT". Do you see any air grills or even a more major part missing?

I've been surprised at how much debries gets through the little holes in the vent grates and onto the cabin filter of my LS. But acorns? Either its a bad design or something in the cowl vent area is loose or missing on your RX.

The following diagram shows your cabin filter and where it intakes air from the cowl vent: http://www.toyodiy.com/parts/p_U_2005_LEXU...WAGKA_8714.html

We're definitely starting to rely on the toyodiy website.

Eldo- I think you might want to look for damage to the "outside air entry" plastic grills. I have worked on cars that have had rather large holes in those grills made by small animals that like to chew on those type of things under the hood. There are quite a few of that type of animal in different areas of the world, including the U.S.A. I have seen rats chew heavily on almost anything made of plastic or rubber under the hood. I've even seen them chew on the tires of a car. There is no way those acorns should be able to get through the openings that the air comes through. I'm betting you'll find holes chewed that are large enough for the (probably ground squirrels since you are in the Mid-West) to get inside to stash their nuts where you found them. You would have been a big disappointment to some hungry squirrel had you moved out of the area before winter comes.

I posted a smiliar note yesterday but see it did not register. I wish to thank those who responded to my query regarding the acorn nest in the cabin air filter box. I appreciated the schematics presented and the other thoughts. I was able to finally locate the actual intake point in the firewall by removing some of the plastic grids and shining a flash in the direction of the cabin filter box, then viewing the light from the box. I still cannot see how the critter made his entry, as all plastic grills and trim seem to be intact and in place. I have decided to keep the car garaged for the next few weeks until snow cover, and have also located some easy roast squirrel recipes. I will keep an eye on this site for any additional suggestions. Thanks for your help.