Dirt in air filter

[cidion]

I changed the air filter in our car last night. It was the first time since we got the car. I guess I should have done it sooner, but at least I did it now.

 

I was surprised to see quite a bit of dirt on the "inhale" side of the filter (windshield side), and even a little on the intake side.

 

I cleaned them out as best as I could. The dirt was oily (but not blowby oily.. almost like K&N oil oily...but the filter was not K&N, nor was the filter oily), and harder to get out than I expected.

 

Just a few questions about it...

1. Is that normal?

2. Should I NOT have cleaned it out (maybe I loosened up something that was stuck before)

3. How often should I check for that?

 

 

 

here are a few photos: (that's the OLD filter, air goes right to left (if it were standing up)

 

 

 

[Manarius]

I wonder if your PCV valve is shot. Car run weird lately?

[idosubaru]

i think i'm seeing the throttle body. i'd clean that out and clean the throttle plate off really well.

 

replace your PCV valve with a Subaru OEM valve. see if that helps, it will if this is PCV valve related. people actually install oil catchers in line with the valve cover vent hoses to prevent oil from getting into the intake like this.

 

this could also be due to excessive crankcase pressure caused by blowby past the rings. thicker oil is about the only thing that will alleviate that besides major engine issues. i wouldn't try this until you replace your PCV valve though and make sure your hoses are all cleaned out.

 

knocking the crud out of your filter as best as you can shouldn't hurt anything.

[porcupine73]

What year/model vehicle do you have? It looks a lot like my '00 2.5L intake. Anywho, for whatever reason the Subaru doesn't have any 'breather' filters like I've seen in other vehicles for the PCV return to intake and valve cover to intake lines (both on the intake side of the air filter). That definitely looks like a little oil blowby or something in there which of course is sticky and then dirt sticks to it.

 

Some amount of dirt after the filter there is normal; no air filter is 100% efficient at small micron sizes. Then that stuff sticks to the oil that's in there.

 

You could consider putting in a PCV return 'catch can'; many people make them from various plumbing and compressed air components.

 

Your throttle body does look like it could use a cleaning; I love to use redline SI-1 in a spray bottle warmed in a hot water bath, block throttle full open, spray in there, wait a while, then brush gently with a soft nylon brush or toothbrush, spray some more, til it melts off, lots of smoke for a minute on startup but clean TB, I accept no liability for this as some manufacturers say there's some coating on the throttle butterfly that can be damaged by cleaning.

 

A shop light and inspection mirror are your friend on this job unless you plan to actually remove the TB.