How To: Replace AVCS Oil Control Valves (OCV's)

One day I was getting off the highway and noticed that one of my AVCS angles was jumping from 0-50*. I was worried that it was my cam gear dying, thus I quickly pulled over and unplugged the offending OCV, which did keep it at 0*. To further test that it was the OCV and not the cam gear, I swapped the OCV's spaces and saw the other side started fluctuating from 0-50*, while the first side was rock solid. This confirmed that it was the OCV's fault and not something else.

 

Part Number for 2005-2006: 10921AA020

Part Number for 2007-2009: 10921AA080

 

This is probably one of the easier things to do on this car, but figured I would grab some pics since the passenger one is kind of painful.

 

Driver side is real easy, pull off the valve cover breather (just one is fine) and pull the OCV straight back. To install the new one just push it straight forward.

http://legacygt.com/forums/attachment.php?attachmentid=253911&stc=1&d=1502330668

 

 

Passenger side is a little more complex:

Remove the intake S bend, pull the valve cover breather off, and unscrew the OCV retention bolt.

 

If you just pull it back like you can driver side one, the OCV retention bracket will contact the coolant tank bracket. This is where you have to get a little creative, rotate it sideways and use a flathead screwdriver to prop it out and push it past the retention bracket.

http://legacygt.com/forums/attachment.php?attachmentid=253905&stc=1&d=1502330668

 

Old vs new, the part numbers are the same but they are made slightly differently. Old one actually had the part number on retention bracket, while new one has last part of the part number on the black plug.

http://legacygt.com/forums/attachment.php?attachmentid=253906&stc=1&d=1502330668

http://legacygt.com/forums/attachment.php?attachmentid=253907&stc=1&d=1502330668

 

Installation is the same way as removal, once again turn it sideways to get it past the bracket. I really had to use a screwdriver to push in past the coolant bracket (was getting caught up on things).

http://legacygt.com/forums/attachment.php?attachmentid=253908&stc=1&d=1502330668

 

After it clears the bracket rotate it to it's normal position, if you wait to rotate it till it's fully in, the head will be in the way of the retention bracket and wont let you rotate it.

http://legacygt.com/forums/attachment.php?attachmentid=253909&stc=1&d=1502330668

 

Reinstall the valve cover breather, of course mine cracked so will have to get replacements soon, meanwhile zip tie to save the day. Air leak here isn't too bad, but still would result in unmetered air coming into the crankcase and then PCV system and then the most maf intake pipe.

http://legacygt.com/forums/attachment.php?attachmentid=253910&stc=1&d=1502330668

Edited October 25, 2017 by covertrussian

Spot on write up once again Covertrussian! Took me less than 15 minutes to swap out the old ones. Appreciate your contributions to the forum!

Thanks for this writeup.

 

 

Its almost comical how easy this was when I think about all the times I have tried to do repairs on this car that should be simple and had me banging my head against the wall for hours.

Thank you @covertrussion for this writeup.

 

Unfortunately, both breather hoses cracked and I am having a hard time finding the right part number for them. Anyone have the part number handy?

Or can I just use generic evap oil grade hose instead?

 

Thanks

I had to look this up and see how it works. Found a pretty good article for anyone interested: https://www.comeanddriveit.com/engine/subaru-avcs-explained

 

Are there symptoms to these? It sounds like the OP was data logging.....I don't.

Thank you @covertrussion for this writeup.

 

Unfortunately, both breather hoses cracked and I am having a hard time finding the right part number for them. Anyone have the part number handy?

Or can I just use generic evap oil grade hose instead?

 

Thanks

 

If you can get a pre-bent molded hose, no reason to go with Subaru ones, unless they are stupid cheap (typically they are not). Even if you can't get pre-bent molded ones, if you route so it doesn't crimp, you should be fine.

 

I had to look this up and see how it works. Found a pretty good article for anyone interested: https://www.comeanddriveit.com/engine/subaru-avcs-explained

 

Are there symptoms to these? It sounds like the OP was data logging.....I don't.

 

Bad gas mileage and loss of power would be the first symptons, eventually a CEL.

If you can get a pre-bent molded hose, no reason to go with Subaru ones, unless they are stupid cheap (typically they are not). Even if you can't get pre-bent molded ones, if you route so it doesn't crimp, you should be fine.

 

Subaru ones were $28 to $34 a piece. I am thinking about just snipping off the cracked part, use a hose coupler and add the generic hose. Sorry but I am cheap

+1 I appreciate McGyvering when something is way too expensive.

+1 I appreciate McGyvering when something is way too expensive.

 

Lol, I figured the hoses are just for venting and nothing complex. $15 total instead of $55 for fixing both cracked hoses plus leftover hose(s) for the next oops

Hey @covertrussian would a set of bad OCV’s cause a 5EAT to stall at random times when coming to a complete stop?

Hey @covertrussian would a set of bad OCV’s cause a 5EAT to stall at random times when coming to a complete stop?

 

Maybe, but that sound more like stuck torque converter lockup or a vacuum leak.

Maybe, but that sound more like stuck torque converter lockup or a vacuum leak.

 

Hmm okay thanks. I noticed my car is leaking oil and it’s burning causing smoke. My mechanic cleaned off the fluid and now there’s fluid again. The stalling happened 2 times in 1 week. I do have some of the symptoms of a failing OVC. Poor mpg engine hesitation etc. no cel

Can the OCV's be cleaned? Just wondering if it is just something you replace or can they be serviced. I am going to embark on a few things under the hood one of these weekends and if they should be included I will tackle them. I am not really experiencing any of the symptoms except she's a bit thirsty but who's to say a cleaning wouldn't help? Thanks.

Can the OCV's be cleaned? Just wondering if it is just something you replace or can they be serviced. I am going to embark on a few things under the hood one of these weekends and if they should be included I will tackle them. I am not really experiencing any of the symptoms except she's a bit thirsty but who's to say a cleaning wouldn't help? Thanks.

 

From what I’ve been told, you can clean them. I need clean or replace them. I’m not too sure what is the best fluid to use to clean them. Others should be able to help on that.

Can the OCV's be cleaned? Just wondering if it is just something you replace or can they be serviced. I am going to embark on a few things under the hood one of these weekends and if they should be included I will tackle them. I am not really experiencing any of the symptoms except she's a bit thirsty but who's to say a cleaning wouldn't help? Thanks.

 

I have been cleaning mine and logging/watching the data from the Cobb APV3. It definitely makes a difference as mine was laggy before the cleaning. I use carb cleaner with the nozzle first followed by PB Blaster. Gently working the mechanism while spraying. After that, carb cleaner again and then fresh oil gently working the mechanism and reinstall. While you are at it, remove the banjo bolts and take out the filters if you haven't done it. Mine were not clogged but definitely sludged up.

 

Btw I am replacing mine, just waiting for the parts to get here. The dealership here in the desert carries nothing and takes forever to get stuff here.

From my research, cleaning may work for a bit, but most everyone seems to end up replacing them not terribly long after. I decided to replace mine at 195k, I would like to think I will get to do it again at 400k miles :-P

Maybe, but that sound more like stuck torque converter lockup or a vacuum leak.

 

Possibly a dumb question but would either cause a CEL?

Possibly a dumb question but would either cause a CEL?

 

In theory yes, in practice, it depends

In theory yes, in practice, it depends

 

Well then lol. Thank you.

Reason I say it like that is, I had a giant vacuum leak for months (one hose popped off), it didn't throw a CEL for months (only after ECU hit 25% correction and 15% learning at idle).

 

My AVCS valve failed while on the highway, I saw it bouncing from 0-50*, never got a CEL. Swapped them sides and the bouncing moved, which told me it was a bad valve and not something else (AVCS cam gear or avcs angle sensor).

 

Torque converter lockup issue? Well never owned an auto so can't speak for that one.

My AVCS valve failed while on the highway, I saw it bouncing from 0-50*, never got a CEL. Swapped them sides and the bouncing moved, which told me it was a bad valve and not something else (AVCS cam gear or avcs angle sensor).

 

Thanks. Didn't think about swapping sides to see. Going to do that tomorrow, that way I can save the "good" one as a spare.

 

Stupid question, when the label says AVCS Left does it mean looking at the front of the car/engine and it is the left side?

Not stupid actually that one can be hard to find, I believe Left is driver side, but I don't 100% recall either .

Thanks. Didn't think about swapping sides to see. Going to do that tomorrow, that way I can save the "good" one as a spare.

 

Stupid question, when the label says AVCS Left does it mean looking at the front of the car/engine and it is the left side?

 

I do not think they have different part numbers, both should work on both sides (if I am not mistaken that is).

The top left is unplugged (AVCS)? I do not know if it is supposed to but the engine I got was a EJ20x and mechanic said it supposed to be unhooked. I am confused..help?

 

Sorry image is bad best I can do in a rush. Thanks!!

Getting a little off topic here. But It's a JDM motor with dual AVCS (intake and exhaust), your USDM ECU only has intake AVCS, thus exhaust AVCS is unusable, hence unplugged.

 

Whether or not that's healthy is beyond the scope of this thread .