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Hey all, got a bit of a problem. I have an 05 WRX STI that I got used with 70,000 miles on it. Owner said the engine had been swapped with a 20,000 mile unit. I have owned the car almost a year now.

Mods it came with:

Invidia cat back exhaust.

Cobb intake

Grimspeed turbo solenoid

AOS of unknown brand

Aluminum mishimoto radiator

Cobb accessport running stage 1 tune of unknown origin.

Mods I installed:

Killerbee oil pickup 

Prosport oil pressure and voltage gauges.

I run Castrol 5W30 premium full synthetic.

Now on to the problem. I was driving home one night, about 12 miles. I was driving spiritedly, but definitely not thrashing it. I pull into a gas station at the edge of the town I live in and notice smoke from under the hood. There is oil all over the passenger side strut tower and on the turbo and down pipe. I check the oil level, and it's right on the money. I decide to drive it the 8 blocks home and keep a close eye on the oil pressure. Oil pressure is fine all the way home, I open the hood and check again. There doesn't appear to be any additional oil on the strut tower or surrounding area.

I have thought for awhile that it gets hotter under the hood than it ought to, but my temp gauge never climbs past the third mark up that's before the red zone.

I have yet to pull it apart and look in depth, in the meantime anyone have any ideas as to what may have happened? My current theory is that the banjo bolt for the oil line on top of the turbo went bad.

As always, thanks in advance.

 

 

 

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1 hour ago, 1 Lucky Texan said:

sure it's oil and not CV grease from a split boot? could it be power steering fluid?

maybe there's a way to pressurize the oil system manually to look for leaks....

 

 

Reasonably sure. It sure as hell looked like engine oil, but by that same token it was dark out. So I'm not 100% sure.

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Throw away the AOS. Those are for idiots and people with blown engines. Buy all the factory PCV and breather hoses and put it back to stock. 

Make sure the turbo stay brackets are in place. If those are loose or missing it can lead to flexing of the oil supply line to the turbo and they can crack. 

Also if you don't know the origin of the tune - get it properly pro-tuned on a dyno before a previous owners bad decision claims your rod bearings. 

GD

Edited by GeneralDisorder
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17 hours ago, GeneralDisorder said:

Throw away the AOS. Those are for idiots and people with blown engines. Buy all the factory PCV and breather hoses and put it back to stock.

Living out in the woods, I've never run across one of these things in the wild.  Seems like a solution in search of a problem.  I mean, how much oil will it actually recover in an engine that still has half-decent compression?

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6 hours ago, jonathan909 said:

Living out in the woods, I've never run across one of these things in the wild.  Seems like a solution in search of a problem.  I mean, how much oil will it actually recover in an engine that still has half-decent compression?

Usually almost nothing on a good engine. And the name is HIGHLY misleading. They are ABSOLUTELY NOT "Air/Oil Separators" - they are "Air/Liquid Separators" and the distinction is very relevant since engines produce large amounts of condensation during warm up. This is generally directed into the cylinders and burnt by the stock breather system. In an AOS it is saved and mixed with the normal small amount of oil vapor to produce a nasty concoction of milkshake-esque sludge that coats and restricts the normal operation of the PCV and breather system. 

It is honestly a horrible idea for a street vehicle. Catch cans and AOSs are RACE CAR parts. They can serve a function in a racing environment to solve specific problems related to ulta-high performance engines. These are engines that see intermittent use and have highly accelerated maintenance requirements - part of which is to clean and service these accessory systems to prevent clogging and empty collection vessels, etc. These are NOT appropriate for street use. 

GD

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Alright, I just finished pulling the car apart. The turbo is PRISTINE. No residue, no shaft slop, nothing. There is oil all over the turbo oil drain hose and the gasket for the metal hose barb, where it bolts to the bottom of the turbo doesn't look very good. So I'm going to replace that gasket and others while I have it out. I will also replace the small rubber oil drain hose, and look into deleting the AOS the previous owner installed.

Currently we're working under the hypothesis that the PCV system over pressurized and blew the excess pressure out that drain line, since it's the path of least resistance.

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