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Oil on airfilter. How?

Posted: Wed Mar 05, 2008 5:15 am
by Kansei
I was driving one day, and my car (96 leg l 2.2 n/a) sputtered and backfired while I was turning left. I figured I was just low on gas but it did it again later on that week. today it was doing it again so I took my car to the gas station put in some gas and thought "what about my intake. it may be restricted or have a leak." so I checked and sure enough there was oil on half of it. and I mean it was covered in it. now I'm curious, how did oil get on there with the stock airbox and no oil leaks. and my oil has been getting low. but I dont beleive I'm burining it, so what else could cause that to happen?

Posted: Wed Mar 05, 2008 5:17 am
by asc_up
Your PCV valve could be shooting it onto it. That's my only thought, but there would have to be a lot of blow-by...

Posted: Wed Mar 05, 2008 5:30 am
by Kansei
I do have a horrible mis in cyl 1 and cant find out why.... so it could be blow-by. so how do i fix that? or can it be fixed...?

Posted: Wed Mar 05, 2008 5:36 am
by asc_up
Wait for others to chime in on what they think it might be before you go do anything.

But first, I'd say get that misfire fixed. If that doesn't solve the problem then install an oil catch can.
Click Here

I think that blow-by usually occurs a little more on turbo cars, though...

Posted: Wed Mar 05, 2008 5:43 am
by Kansei
i dont know what is causing the misfire. ive changed my whole ignition system except the ICM and it still is missing. I'm not too inclined on diagnosing a mis so I dont know what else to check for.... any ideas?

Posted: Thu Mar 06, 2008 8:01 pm
by Legacy777
So are you running a stock airbox & filter, or aftermarket?

I don't see how blow by could make it all the way back to your filter. The engine creates a low pressure (vacuum) the atmosphere is at a higher pressure then your intake manifold, piping, etc. There's no way blow by gasses are going to come out the PCV travel up stream of airflow and higer pressure.

Unless I'm completely missing something here....

Posted: Thu Mar 06, 2008 8:08 pm
by vrg3
The flow patterns in the intake are really funny. There's all kinds of reversion and stuff, especially with the corrugations in the intake tubing. Some oil does definitely make it all the way back to the air filter. If the filter is "covered" in oil, though, that's probably abnormal.

Posted: Thu Mar 06, 2008 8:16 pm
by Legacy777
I don't know.....I just can't see that......


Was the oil on the inside or outside of the filter, or had it soaked all the way through?

Have you checked your MAF?

Posted: Thu Mar 06, 2008 8:17 pm
by vrg3
Pull the MAF sensor off any stock Subaru, Josh, and give the inside of it a little rub with a white napkin. You'll get motor oil on the napkin, I guarantee.

Posted: Thu Mar 06, 2008 8:25 pm
by Legacy777
I used to check the MAF when I ran a K&N and would notice a little bit. I don't recall there really being much of anything when swapping to paper, but I'll check the next time I do some work on the car.

Posted: Thu Mar 06, 2008 8:36 pm
by BXSS
The cyl 1 miss could be a few things.

You said you changed the ignition & it is still happening, but did you change wires or check/change plugs?
If you did not I'd say go with the obvious & change wires/plugs.

A bad injector or low compression on that CYL can cause a miss too.

I'd check compression to see if it is way off the other cyl values.
If it is OK I'd swap injectors around & see if the miss moves to the cyl. with the #1 injector.
If it does move the injector is bad or may need to be cleaned (r/c eng, deusche werks, or someplace like that....)


I've noticed what vrg3 says about oil on the MAF too, I thought it was from the PVC system.

Posted: Thu Mar 06, 2008 8:37 pm
by vrg3
Yes, it is from the PCV system.

Posted: Fri Mar 07, 2008 12:49 am
by Kansei
i have all new plugs and gapped them and my wires are spankin i changed the coils and all that. i just didnt change the ICM thats all. ive been thinking it might be the MAF and or Injector but i havent had the money yet so im going to and It was on the outside of the filter.

Posted: Fri Mar 07, 2008 6:34 am
by vrg3
Is it possible you just haven't changed your air filter in a loooooong time? The oil could have collected over an extended period of time.

Posted: Fri Mar 07, 2008 8:24 am
by AWD_addict
vrg3 wrote:Is it possible you just haven't changed your air filter in a loooooong time? The oil could have collected over an extended period of time.
Yeah, get a clean air filter and clean out the intake. See if it gets messy again.

Posted: Fri Mar 07, 2008 11:19 pm
by Kansei
i will this coming friday and ill let you guys know what happens. thanks. but it was clean when i bought the car.

Posted: Sun Mar 23, 2008 10:45 am
by Kansei
ok i put a new air filter in and its getting oil on it again. there is a black spot after about 10 min. so now what. OKSC is telling me I need a new PCV so thats on the list. what next?

Posted: Sun Mar 23, 2008 5:25 pm
by vrg3
Yeah, replace the PCV valve and make sure all the PCV plumbing is intact and clean inside. If you're still covering your air filter with oil after that, I'd guess you have a problem with piston rings not sealing right.

Posted: Sun Mar 23, 2008 7:39 pm
by Kansei
well im pretty sure my piston rings are shot. but i havent had the money to buy a new motor yet so Im looking for a quick fix. does oil catch can and new pcv look like a good idea?

Posted: Mon Mar 24, 2008 3:41 am
by vrg3
Definitely the PCV valve and pipes/hoses.

I don't know about the catch can.

Are you certain the oil on the filter is what's causing the rough running?

Posted: Mon Mar 24, 2008 4:32 am
by Kansei
no I'm not so sure. its just a kids idea.(me being the kid) and I want it fixed so I kinda jump into conclusions. Like I'm not so sure my piston rings are bad. but I want to believe it.(so I can get a new motor), but the guy I bought the car from said it was"catastrophic electrical failure. no speedo, no odo, no start till I fixed that. now the rough running.

Posted: Mon Mar 24, 2008 4:40 am
by vrg3
Have you given the car a tuneup yet?

Don't believe things without reason to believe them. Science works better.

Posted: Mon Mar 24, 2008 3:21 pm
by internetautomart
do you have access to multimeter?
a compression tester?
I would check resistance on the injectors, and the compression on the motor.

Posted: Tue Mar 25, 2008 4:59 am
by Kansei
all of those are done. it really sucks. the compression test is the only one I havent gotten to. new plugs wires and coils. new oil and filter.