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Old 07-02-2019, 05:19 PM   #1
vrios969
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Member#: 493613
Join Date: Nov 2018
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Location: Chicago
Vehicle:
2006 WRX Wagon
Black

Default Changed out PCV, notcied oil in intercooler.

Hey everyone, im kinda new here and am a beginner on wrx stuff. I own a 06 wrx wagon, 2.5 turbo, 5speed. I would get wiffs of oil when stopping and could never find the source. It does burn thru oil, switched to T6 , now it burns less oil about 1 quart every 3k miles. Anyways, I stumbled upon a comment saying it could be the PCV, im not a mechanic and dont have many tools but i ordered the part and got it out amd replaced in about 2hrs. In the proccess i noticed oil in some lines and intercooler, is this bad? How much oil is too much? What does this mean?
Thanks in advance.

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Edit: it says i dont have permission to post pictures. I'll figure out how to get some on right now
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Old 07-02-2019, 05:39 PM   #2
vrios969
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Default Found out how to post pics

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Old 07-02-2019, 06:53 PM   #3
n2oiroc
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pretty normal. grab a can of brake cleaner and hose it out good.
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Old 07-27-2019, 04:51 PM   #4
contaminatrix
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45A, originally 18L

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yep. normal.

in case it isn't, it could be the following

1. residual oil from before the pcv change
2. turbo passing oil
3. new pcv is being stubborn

do the pcv delete and be at peace. i did that and i have a dry dry dry intake :-)
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Old 07-29-2019, 12:42 PM   #5
jthewarrior
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Howdy, apologies for the long reply.
TL/DR: Look for leaks on your engine. A quart every 3000 miles is kinda worrisome. Keep an eye on the oil level, I'd check every 1000 miles to be safe. PCV system is probably OK.

A little background on me: I'm a design and release engineer for an American OEM. I work on engine ventilation/PCV(positive crankcase ventilation) systems and sealing components. I know how engine breathing works and have been doing the job for about 11 years now. I am not a mechanic however, so please consult one before doing any major work or modifications on your vehicle.

When we find excessive oil in the intake it usually indicates these things:
  1. Something in the system, like a valve, is broken or plugged. You replaced the valve, it should be fine. It could be other things, but for now assume you fixed it.
  2. The engine is producing a lot of blowby, which is air that gets past the piston rings. You can perform a leakdown and compression test to check your piston to cylinder sealing (a PITA in a boxer engine and you need the tools to do this). For you, let's skip this.
  3. The engine is being run at a point in which the system is poorly equipped to handle Most PCV systems are passive and therefore are not super efficient at all speed/load points. High speed, low load points are esp. bad for blowby and excessive oil pull over/draw into your intake. I assume this isn't the case for your daily driver.
  4. The vehicle is doing a lot of high G turns and braking. Oil can be pulled over in bigger slugs of liquid as it's forced into the sides of the engine or valve coves by high G forces. I assume this isn't the case for your daily driver.
  5. Oil leak in the turbo. Turbos get fed oil for their bearings, but are also smoking hot, so these seals can start to fail. However, if you don't have black smoke out of your tailpipe, you are probably ok.
There are other reasons, but these are the main ones.

All that being said, to answer your original question of "is this a lot of oil", a little oil in the intake is normal for most modern vehicles with PCV systems. Being a quart low after 3000 miles is kind of a lot.
The main thing is to watch your oil consumption very carefully. You don't want to be more than a quart or a quart and a half low.
I think if you are getting whiffs of oil when you stop that's an indication that the oil is on the outside of the engine; I.E. a leak. Pull off any bottom shielding you have on your car and check things out. Valve cover gasket leaks are common problems with boxer engines.
(Note that changing to a different type of engine oil is not going to slow down a leak or stop oil consumption or pullover.)

QUESTIONS:
Are you getting smoke out of the tailpipe? If so when does it happen, when you get on the throttle?
Any oil spots on your driveway?
How many miles on the car?
Is it your daily driver? Any racing?


In regards to the PCV delete, I'm not sure what that entails. The engine has the PCV system so it can cycle dirty air (containing oil mist, fuel and water vapor) out of the crankcase , and bring clean air in. This helps with oil life and ultimately engine life. My advice is to keep the PCV system as it is for now until you gather more data and evidence that there are no leaks.

Hope this helps and again apologies for the long reply,
Jay.
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Old 07-30-2019, 01:40 PM   #6
contaminatrix
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pcv recirculates oil vapours back into the intake. the exits are connected to the intercooler pipe and then extended into the turbo intake. it's only good for emissions and such, but bad for your intake tract.

search for pcv delete mod and see the results. either way if you keep it or delete it, ok! :-)
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Old 07-31-2019, 11:24 AM   #7
jthewarrior
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I did a search for the PCV delete Mod and I found about 20 different versions of people doing 20 different things to fix the oil in the intake problem. Can you tell us what you did on your car? I think it would help vrios969.

That being said, I still strongly suggest that vrios969 NOT plug the PCV valve. If anything, installing a catch jar inline with the PCV hose which drains to the pan, would be the suggestion I would make if there are no external oil leaks on the car.
Another member here, Dave (dblotii.....design engineer with 25 years of experience), has a good explanation of why we shouldn't plug the PCV valve:

Quote:
Originally Posted by dblotii View Post
Another reason not to remove the PCv valve is that if you remove the valve and block the PCV valve connection, you aren't actually ventilating the crankcase with fresh air. Remember that blowby gasses contain water vapor, Hydrocarbons and NOx. The water vapor and NOx degrade the oil much faster if there is no PCV valve (or orifice) to continually purge these substances from the crankcase (whenever your throttle is not wide-open). Your oil will sludge up and oxidize much faster without a PCV valve. Also the HC's in the blowby gasses are fuel that is best burned in the combustion chamber rather than just wasted.

Dave
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Old 08-01-2019, 10:59 AM   #8
contaminatrix
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45A, originally 18L

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well, let me try give an idea.

1. The hose that enters the turbo intake, was removed and the turbo intake entry plugged.
2. The hose that went under the manifold was removed and plugged.
3. The PCV that went under the manifold was removed.
4. The empty space under manifold was plugged.
5. I added a minifilter to the metal pipe a-top of the intercooler where the vapours from the head exit from.

Intake is as dry as a bone.

Now if you do this and STILL find oil in the intake, it's the turbo :-)
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Old 08-01-2019, 01:25 PM   #9
jthewarrior
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BLUE

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That makes sense that you have no oil in your intake, since you closed off all of the air passages to the intake or clean air duct from the crankcase. The engine is breathing through the mini-filter you installed. Any trace of oil around that thing?
Just keep up on your oil changes to keep the oil from becoming sludge.
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Old 08-02-2019, 08:31 AM   #10
contaminatrix
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45A, originally 18L

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nope. it's also dry. i leave them to vent to air. plan is to have them further out back closer to the exhaust.

i keep my oil temps low at around 83-90 degrees C, even at boost. Only once after a few 1000 kms do i let it go above 100 to boil out anything that can be boiled out.

it's my dd so i care for it like i care for my granma
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Old 08-08-2019, 07:48 AM   #11
rorygtb
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Default oil residue

Much to mirror what posters have said above,

some oil in the inlet tract and intercooler seems normal for turbo subarus.
Remember, the PCV is only one vent for excess crank pressure. There are also two hoses (one on either side of the heads) which vent pressure. I installed a catch can to my pcv setup thinking it would solve my oily intercooler issues and I can still see some in there when I look.
As long as the car doesnt smoke on boost, feels to have good power and doesnt use an abnormal amount of oil, I wouldn't worry!

Again, a compression test will put your mind at rest if you are concerned about leaky piston rings.
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