Welcome to the North American Subaru Impreza Owners Club Saturday December 7, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L Turbo)

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 11-10-2024, 01:40 PM   #1
2gnt2wrx
Scooby Specialist
 
Member#: 123625
Join Date: Aug 2006
Chapter/Region: NESIC
Location: Dover, NH
Vehicle:
2015 WRX
Galaxy Blue

Default 2005 STI oil burning problem

Car has under 100k/mi original engine. Noticed it sucked down a half a quart or so of oil in 200miles, smoke comes out of tail pipe only under boost. Stage2+, Crawford v2 AOS. Car doesn’t get driven often. Car runs and drives normal, no noises, or anything that would suggest the engine is blown. I’m getting very frustrated at this point with the situation and looking for advice. Oil used is 5w 40 motul, engine has good oil pressure. Should I clean the AOS out? Stuck oil control ring? Thanks in advance.

What I’ve done so far
-Pulled tmic 35 times and it has oil every time. Except when I ran the AOS to atmosphere. Don’t worry I monitored my AFR’s.

-No smoke out of the oil fill neck when warm.

-installed 3MI AOS drain to turbo drain.

-checked pcv routing… initially I did have a line crossed up by accident but fixed it.

-did an initial compression test before seafoam. 136-143psi on all cylinders.

-Ran Seafoam through intake track.

-Compression test after cyl1- 145psi, cyl2- 139psi, cyl3- 144psi, cyl4- 138psi.

-Leakdown test cyl1- 4%, cyl2- 7%, cyl3- 4%, cyl4 6%.

-cleaned the tmic with gasoline, and drive the car another 120miles and burned another 1/4 quart.

-Pulled exhaust manifold and no oil coming from the exhaust valve seals.

-swapped turbo’s no oil coming from the exhaust side of either turbo.

-Borescoped all four cylinders, noticed a small amount of oil sitting at the bottom of each piston bore.

-Borescoped the intake valves couldn’t see any oil coming from I take valve seals on the o es I could reach.
* Registered users of the site do not see these ads.
2gnt2wrx is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 11-10-2024, 04:47 PM   #2
AndrewsSubaru
Scooby Newbie
 
Member#: 534243
Join Date: May 2023
Vehicle:
1992 Legacy Turbo
2006 WRX, 2005 9-2x Aero

Default

If your AOS is properly routed/set up you should not have any oil in the inlet or intercooler, even more so because your engine is stock. I installed both IAG and crawford aos's in my cars and they work great.

I'm willing to bet you have a kink/clogged/not proper line somewhere. It sounds like you're not venting properly and under boost pressure you're pushing oil out of the breather ports straight into the inlet. When you ran it to atmosphere whatever oil the aos caught went out instead of being burned

If you triple checked all the hoses the only other thing I could think of is the drain inside the aos is clogged, you could shoot some brake clean in one of the vents and see if anything comes out the bottom, or shove a rag or something in there to try and clean it
AndrewsSubaru is offline   Reply With Quote
Old 11-10-2024, 05:19 PM   #3
2gnt2wrx
Scooby Specialist
 
Member#: 123625
Join Date: Aug 2006
Chapter/Region: NESIC
Location: Dover, NH
Vehicle:
2015 WRX
Galaxy Blue

Default

Thank you, I tried blowing through the top and there was some resistance coming through the drain side. I’m
Going to try cleaning it somehow, brake cleaner or gas. I’ll post my findings.
2gnt2wrx is offline   Reply With Quote
Old 11-11-2024, 03:17 PM   #4
2gnt2wrx
Scooby Specialist
 
Member#: 123625
Join Date: Aug 2006
Chapter/Region: NESIC
Location: Dover, NH
Vehicle:
2015 WRX
Galaxy Blue

Default

Pulled everything apart: checked all lines, no kinks, no obstructions, blew through everything all clear, cleaned the AOS with gasoline then brake cleaner, and rechecked all hose routing. Still small clouds u see boost.

Last edited by 2gnt2wrx; 11-11-2024 at 08:50 PM.
2gnt2wrx is offline   Reply With Quote
Old 11-12-2024, 01:29 PM   #5
TurboRev
Scooby Newbie
 
Member#: 463945
Join Date: Mar 2017
Default

I'd start by giving the AOS a good clean. Make sure the drain and any screens inside are clear so oil doesn't build up and end up getting sucked into the intake when you're boosting. You can use some brake cleaner or compressed air to flush it out. Then, go over all the PCV hoses and the valve to be sure there aren't any tiny kinks or clogs that could be causing pressure issues and pushing oil where it doesn't belong.
TurboRev is offline   Reply With Quote
Old 11-15-2024, 11:14 PM   #6
Nomiezvr-4
Scooby Newbie
 
Member#: 538322
Join Date: Jun 2024
Default

Id yank the AOS if you don't track or auto-x the car to see what happens. My car makes 370whp on e85, no AOS i street drive it, haven't had a need for an AOS yet.
Nomiezvr-4 is offline   Reply With Quote
Old 11-17-2024, 11:53 AM   #7
AndrewsSubaru
Scooby Newbie
 
Member#: 534243
Join Date: May 2023
Vehicle:
1992 Legacy Turbo
2006 WRX, 2005 9-2x Aero

Default

Did you keep that metal piece under the intercooler? I just remembered I removed it because it was completely full of gunk and I ran the hoses straight to the breathers instead. So I'd check that too.

If it's clear, you could try to run the aos breather port to some kind of plastic bottle (somewhere it won't melt) and see how much oil you catch if you're still having issues. Adding an aos shouldn't cause so much blowby but without seeing the car in person it's hard to say what the issue is
AndrewsSubaru is offline   Reply With Quote
Old 11-19-2024, 10:50 AM   #8
benflynn
Scooby Specialist
 
Member#: 515308
Join Date: Jun 2020
Default

Could it not be a broken ring land? Only sever oil using without noticeable smoke has been cyl 4 ringland. And out of the dozen or so short blocks I have had apart only one had no cracked ringlands.
benflynn is offline   Reply With Quote
Old 11-19-2024, 02:20 PM   #9
AlexL
NASIOC Supporter
 
Member#: 192988
Join Date: Oct 2008
Location: CT
Vehicle:
2005 WRB GD Wagon

Default

What was wrong with the PCV initially? If you pressurized your crankcase once upon a time, you may have blown some seals irrepairably and now you have more blowby than normal, which won't be fixed except by taking things apart. I would vent everything to atmosphere, to test, disconnect and plug the PCV. If it's still smoking, that's your rings.
AlexL is offline   Reply With Quote
Old 11-19-2024, 02:23 PM   #10
2gnt2wrx
Scooby Specialist
 
Member#: 123625
Join Date: Aug 2006
Chapter/Region: NESIC
Location: Dover, NH
Vehicle:
2015 WRX
Galaxy Blue

Default

It’s a possibility but would it be the case if it had good compression and leak down numbers?

Oil appears to be leaking out of the compressor housing of the turbo now.
2gnt2wrx is offline   Reply With Quote
Old 11-19-2024, 06:50 PM   #11
benflynn
Scooby Specialist
 
Member#: 515308
Join Date: Jun 2020
Default

Oil out compressor can high crank pressure or the pvc is dumping into the turbo inlet. I second the dump to atmo and see what’s up.

Also a boost leak will cause oil past the compressor.
benflynn is offline   Reply With Quote
Old 11-19-2024, 06:54 PM   #12
benflynn
Scooby Specialist
 
Member#: 515308
Join Date: Jun 2020
Default

I can’t say from experience leakdown numbers associated with the broken piston. I am very quick to pull one apart since I do my own work and believe anything with oem top ring gap is or will be broken before long. I will say oil loss is the only symptom I have seen from one.
benflynn is offline   Reply With Quote
Old 11-20-2024, 09:50 AM   #13
AlexL
NASIOC Supporter
 
Member#: 192988
Join Date: Oct 2008
Location: CT
Vehicle:
2005 WRB GD Wagon

Default

Quote:
Originally Posted by 2gnt2wrx View Post
It’s a possibility but would it be the case if it had good compression and leak down numbers?

Oil appears to be leaking out of the compressor housing of the turbo now.
But it only smokes under boost? A bad turbo seal would smoke all the time.
AlexL is offline   Reply With Quote
Old 11-20-2024, 04:00 PM   #14
AndrewsSubaru
Scooby Newbie
 
Member#: 534243
Join Date: May 2023
Vehicle:
1992 Legacy Turbo
2006 WRX, 2005 9-2x Aero

Default

He ran vta already which is why I suggested running into a can or something. You'll be able to tell if it's blowby mix or pushing mostly oil through (I'm guessing it would be oil)

There has to be something we're missing since the compression and leakdown seem ok. I don't know what else it could be other than pcv or turbo
AndrewsSubaru is offline   Reply With Quote
Old 11-20-2024, 08:10 PM   #15
2gnt2wrx
Scooby Specialist
 
Member#: 123625
Join Date: Aug 2006
Chapter/Region: NESIC
Location: Dover, NH
Vehicle:
2015 WRX
Galaxy Blue

Default

I ran it to an aluminum can and drove 200 miles, nothing of note in the can.

I’m considering returning the pcv system to stock… which is quite an ordeal since I blocked the pcv valve when I redid my intake manifold. This should eliminate the AOS as being the culprit. There are some reports of people having issues with the Crawford.

Last edited by 2gnt2wrx; 11-20-2024 at 08:41 PM.
2gnt2wrx is offline   Reply With Quote
Old 11-21-2024, 05:22 AM   #16
danger1138
Scooby Specialist
 
Member#: 279525
Join Date: Apr 2011
Chapter/Region: Tri-State
Location: Arkansas
Vehicle:
06 Fxt

Default

If there was no oil inside TMIC when you dumped/vented the AOS to atmosphere; keep it that way.
Im running IAG AOS; tuned my vehicle with it routed the "street version" way. Everytime i pulled off my TMIC i had oil inside TMIC, on the couplers etc..

I have since routed the IAG aos to the "Comp version"; dumping to atmosphere and there is a stark difference. Very little to no oil inside TMIC & friends.
danger1138 is offline   Reply With Quote
Old 11-21-2024, 08:39 AM   #17
benflynn
Scooby Specialist
 
Member#: 515308
Join Date: Jun 2020
Default

Quote:
Originally Posted by AndrewsSubaru View Post

There has to be something we're missing since the compression and leakdown seem ok. I don't know what else it could be other than pcv or turbo
I don’t know if I agree.
benflynn is offline   Reply With Quote
Old 11-21-2024, 12:38 PM   #18
AndrewsSubaru
Scooby Newbie
 
Member#: 534243
Join Date: May 2023
Vehicle:
1992 Legacy Turbo
2006 WRX, 2005 9-2x Aero

Default

If there was a bent valve, broken piston or a broken ring it would've shown up no? Unless it was poorly maintained and oil changes were extended the likelihood of a stuck oil ring seems pretty low. However it is a subaru and stranger things can/do happen I suppose
AndrewsSubaru is offline   Reply With Quote
Old 11-21-2024, 04:51 PM   #19
cboggess
Scooby Specialist
 
Member#: 30804
Join Date: Dec 2002
Chapter/Region: SWIC
Vehicle:
87 Yugo
Red

Default

I'm betting stuck rings on this one. Yes. You can still have great compression and have stuck rings. I know. Personally. Because I've done it. Yeah, yeah, I know. I was busy with life and kept putting off my oil changes. Yeah yeah, I know. No really. I do know. Seriously. Yes. I'm a dummy. I'm not arguing with you. Anyway...

Here is what I have done in this case, and had success with:
Buy 2 cans of liquimoly engine flush.
Buy some cheap oil you run in your weight
Buy some cheap filters
Buy a can of seafoam or fuel injector cleaner (skip this if you run e85 which I doubt you are doing because I don't think the rings would stick if you were)

Dump can of engine flush in engine. Run for the 10-15 minutes idling as they recommend.
Turn the car off, and tell it you'll see it tomorrow.
Next day drain oil. Remove old filter.
Install new filter. Fill with fresh cheap oil.
Dump half a can of seaform or injector cleaner into tank.
Go for a drive. Just a nice long drive. Don't beat on it. Just drive it.
Bring it home. While it is still hot dump the second can of engine flush in it. Let it idle the 10-15 minutes. Say good night.
Next day drain cheap oil out. Remove filter.
Install new filter. Fill with fresh cheap oil.
Dump remainder of seafoam in the tank.
Drive like a normal person for a few hundred miles.
Go back to your normal, good synthetic oil and good filter.
cboggess is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 03:36 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.