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Discussion Starter · #1 · (Edited)
I have almost 30kms on my 2015 sti and while changing the oil I noticed this thingy on the head leaking oil. The ground strip attached to it was totally coated in old oily residue before I took this picture. The 4 bolts attached each had drips of oil on each bolt head, so its leaking...


What is this component, why is it leaking?
(sorry for the upside down picture)



 

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That is your exhaust AVCS solenoid AKA VVT solenoid. it uses oil pressure to advance/retard cam timing ( i believe)

I believe Subaru uses a gasket for those, so it may be a simple gasket replacement but I'd have to check the parts list
 

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i had mine leak from the plug/junction. the O-rings for that for some reason wasnt keeping the oil in - had to replace teh whole unit (i didnt buy the solenoid seperately since they didnt really have it listed sperately in the parts manual - so bought the whole assembly).

i'll put the link for that part:

CYLINDER HEAD. SYSTEM.. For 2015 Subaru STI 2.5L TURBO 6MT STI | Subaru Parts Online

specifically:

2015 Subaru STI 2.5L TURBO 6MT STI Holder assembly-oil control valve. System, head, engine, cylinder, cooling - 10917AA070 - Genuine Subaru Part

and gasket:

CYLINDER HEAD. SYSTEM.. For 2015 Subaru STI 2.5L TURBO 6MT STI | Subaru Parts Online

edit:

you could also double check the torque on those, make sure it's torqued down to spec. if it's within spec.
 

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i had mine leak from the plug/junction. the O-rings for that for some reason wasnt keeping the oil in - had to replace teh whole unit (i didnt buy the solenoid seperately since they didnt really have it listed sperately in the parts manual - so bought the whole assembly).

i'll put the link for that part:

CYLINDER HEAD. SYSTEM.. For 2015 Subaru STI 2.5L TURBO 6MT STI | Subaru Parts Online

specifically:

2015 Subaru STI 2.5L TURBO 6MT STI Holder assembly-oil control valve. System, head, engine, cylinder, cooling - 10917AA070 - Genuine Subaru Part

and gasket:

CYLINDER HEAD. SYSTEM.. For 2015 Subaru STI 2.5L TURBO 6MT STI | Subaru Parts Online

edit:

you could also double check the torque on those, make sure it's torqued down to spec. if it's within spec.
The real MVP
 

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I've developed this same leak on my 2010 STi. Just ordered the OCV holder assembly and gasket.

Before I start taking things apart I was hoping to confirm that doing this will drain most of the oil from the motor. I don't have any experience with this system, but I'm guessing that since it's bolted to the underside of the head most of the oil in there will drain out when it's removed. But maybe not all of it since it's located higher up than the oil pan drain plug? Would it be a good idea to just drain the oil first, replace the assembly, and then refill?

If anyone who's done this repair would be willing to share their experience I'd greatly appreciate it.
 

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I've developed this same leak on my 2010 STi. Just ordered the OCV holder assembly and gasket.

Before I start taking things apart I was hoping to confirm that doing this will drain most of the oil from the motor. I don't have any experience with this system, but I'm guessing that since it's bolted to the underside of the head most of the oil in there will drain out when it's removed. But maybe not all of it since it's located higher up than the oil pan drain plug? Would it be a good idea to just drain the oil first, replace the assembly, and then refill?

If anyone who's done this repair would be willing to share their experience I'd greatly appreciate it.

if memory serves me right...

it wont drain all the oil. it'll only spill whatever oil is in that particular area. most of the oil sits in your oil pan.

Shoudl still have something to collect the oil. i cant recall since i did this a few years back, but my memory is saying its like half a cup of oil or so. STILL... get somethign to collect the oil.

Also look up the torque specs for those bolts, and bolt torquing sequence (i'm guessing its a star/criss cross pattern, kinda like the sequence to tightening ur lugnuts).
 

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my memory is saying its like half a cup of oil or so.
Awesome, thanks for the info. I would've expected quite a bit more than that and was leaning towards just draining the oil before taking things apart. I just did an oil change not too long ago (when I noticed the leak) so avoiding another will save some time and $$$.

Also look up the torque specs for those bolts, and bolt torquing sequence (i'm guessing its a star/criss cross pattern, kinda like the sequence to tightening ur lugnuts).
Also great advice. I think I found the torque specs but they seem low (7.4 lb-ft). I'll post some pictures from the service manual in a minute. Can't seem to find anything about the torque sequence.

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Okay, here's the diagram from the service manual and the key. I've highlighted the parts that I think are correct and the torque spec for the bolts is 7.4 lb-ft. Didn't realize they'd be on there so loose. Maybe I should've just checked the torque before I ordered the parts...



 

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i've attached an image from a 2012 subaru FSM. torque specs look low, yup. hope u got a reliable 1/4 torque wrench. yeah wasnt sure about the sequence. looks like FSM doesnt mention it so you're good to go! i'd still star pattern/criss cross it but *shrugg*

those light torque specs always get me paranoid. the old 'gutentite' adage messes me up for these low torque stuff.
 

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There is a FT86 company that makes a shield for that solenoid.
 
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