Dirty air filter '08 Civic

Just finished replacing the air filter and the cabin air filter. Dirtiest I have ever seen. We got the car 2 yrs ago w/ 37K miles. Now has 66K miles. The old filters are Honda, so likely they are the originals (shame on me for neglecting this trivial maintenance, but the car is here only one evening a week.)

On the air filter, intake side (bottom) was filthy black. At first I thought it was oil, but it’s dry black dirt. No oil in the plenum (box) in which the filter sits. Is this simply from overdue maint, or should I be looking for something more serious?

Hi Art1966,

Really depends on where you drive. As long as it’s not wet, I wouldn’t worry too much.

Unless the filters are HEPA filters, it’s normal to see some dust on the clean side of the filters if they’re used too long. A true HEPA filter will remove dust particles down to .3 micron. And the filters used in your vehicle aren’t HEPA filters. If they were, they’ld cost $100.00 apiece.

Just change the filters more often.


As long as it was pretty clean downstream it’s okay.
Air filters actually filter BETTER as they fill with dirt, just don’t want it to get too restrictive:

This car looks like it was parked outside its entire life in a dirty environment. Or it was driven arournd an industrial accident where there was a sooty fire. Or the car was submerged and covered in mud which was cleaned up except for the cabin air filter. Check other areas and cavities for dirt.

I change cabin air filters every 2 years and it’s nearly clean.

The Honda filters are supposed to be changed every 20,000. You can get Honda brand on line for a reasonable cost.

Thank you all for the reassurance. I promise to be more diligent in changing the filters.

Bing, who sells genuine Honda filters on-line?

Just search for “genuine honda oem parts” to find a list of people who sell Honda parts online. However, I don’t think you should go through all that trouble. An aftermarket brand, like Fram, Purolator, or whatever brand the auto parts store carries should be fine. I’ve been using non-Honda air filters in my 1998 Civic for as long as I can remember.

I bought cabin filters from rockauto, they’ll have quite a few air filters for the Civic, I’d think.

A cabin filter as clogged as the one in your photos (is that a dragonfly wing?) could easily slow the airflow down sufficiently to allow dust to collect in the ductwork leading to and, and maybe even to force the air to find a way past the filter and allow who-knows-what to collect on the duct sides beyond it. If t were me, I’d buy somne attachments for the shop vac and clean the ductwork out.

Nice phots, by the way.

Yeah Google is your friend. I’d have to check my receipts but handa.com and delrayhonda come to mind. Sometimes you have to go to other sites to make sure you get the right part numbers. Filters run about $25. Don’t know what they are at the dealer now.

That was my photo of an HVAC filter that hadn’t been changed in 2 years of continuous use.

$8-$12 for Fram/Wix/etc from Rockauto. I have no problem using aftermarket air filters, as long as they’re a name brand.