Dust on intake

[MrClutch]

Today I was cleaning my engine compartment,and at the same time I took my air filter out to see its condition. I changed it 12k miles ago and now the white filtering media looks kind of greyish... I live in LA so there isnt a lot of dust here. Anyway at the throtle body there is a thin layer of dust on and around it. I didnt see any dust when i put that filter in. Is this normal. Do I have a leak or it's simply not a good filter. Any help would be appreciated.

By the way, This is an STP air filter with media that is thick and looks and feels like cotton, looks very different from other brand filters, which are paper based.

 

[Drew99GT]

I just noticed the same thing with my 94 Corolla. Just put a new filter in there a few months ago and now there's a thin layer of dust all throughout the intake tubing past the filter. To be honest, I didn't really look to closely at the intake before this weekend so it may have been there all along, but i had taken a quick peek at it before and I didn't see the dust that I saw this weekend. Who knows. Clamps are all tight and the filter fits great (OEM Toyota).

 

[kenw]

filters do not and cannot catch everything. If they did your car would suffocate. Anything smaller than the filter openings WILL get thru, and in most cases it won't hurt a thing.