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'98 white GT wagon, '99 red GT wagon, '06 Outback wagon (green)
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Discussion Starter #1
Hey everyone. I have a 2006 outback that is going through a lot of oil since I did the head gasket and engine overhaul.
I got the car used from a dealer, he said that one of his guys had the head gaskets done. I learned there were lots of things that were not done the way they should’ve been. I made sure I kept it will level at the proper capacity, and plan to do a head gasket overhaul. Or use the Fel-Pro head gasket in lower refurbish kit. While I was in there of course I did the rear main seal.
Now I’m going through a quart of oil at least every two weeks. I was getting intermittent O2 sensor malfunction’s so I switched it out with a used sensor. I keep getting the same code but at variable intervals: low catalyst threshold bank one.
I removed a lot of carbon deposits from the crown of the pistons, but I examined the crosshatching on the cylinder walls and it was very visible. There’s no sign of rod knock or piston slab or Val taking. The car runs very strong all the way to redline. I have even use UV dye to try to pinpoint the leak, but the only thing I can find is a minor leak around the oil filter. I see no oil coming from the other part of the car. I did not actually have the valve stem seals changed because I did not take the heads apart. I’ve never done it on this type of engine and ( the variable intake cam). I did not want to get it apart and find I cannot get it back together again.

Could the oil seals around the valves be leaking enough oil under pressure to be causing the amount to drop that I’m seeing? Any help would be greatly appreciated!

Merry Christmas to all!!

MacDad
 

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Outback 2011 3.6R Premium
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1,043 Posts
Have you checked the operation of the PCV valve? If this is not functioning properly it can cause excessive oil usage.

Seagrass
 

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'98 white GT wagon, '99 red GT wagon, '06 Outback wagon (green)
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9 Posts
Discussion Starter #3
I believe I replaced it when I did the job. However I will investigate to be sure. Proper functioning should have the check valve freely moving with in the housing of the valve correct?

Thank you!
 

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'98 white GT wagon, '99 red GT wagon, '06 Outback wagon (green)
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Discussion Starter #4
Also, what is the mechanism by which I would experience more oil consumption if the PCV valve is not operating correctly?
 

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On the Super Mod Squad
2002 Pair: 3.0 VDC Wag & 2.5 Limited Sedan
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25,796 Posts
get a new OEM PCV. (edit: and inspect its fittings / tubing for pinches/ breaks / softness if rubber)

dealers can do really poor head gasket work.
heads: get them professionally machined, = something dealers skip, and a EJ253 should be machined.
swap all oil seals.

hope your cats are not too far gone already = if you pull the front o2 sensor right out and run it do you get oil dripping at any time / any temp ?
 

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Outback 2011 3.6R Premium
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Also, what is the mechanism by which I would experience more oil consumption if the PCV valve is not operating correctly?
The PCV valve is designed to maintain “positive crankcase ventilation” in other words it controls the pressure in the bottom end (the crankcase) of the engine.

In simple terms, if the PCV valve is stuck open the crankcase vents directly to the air intake and if it is stuck closed the crankcase pressure increases too much causing “blow by” of engine oil from the crankcase past the pistons and rings into the combustion chamber. Both of these situations can lead to excessive oil consumption.

Seagrass
 

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'98 white GT wagon, '99 red GT wagon, '06 Outback wagon (green)
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9 Posts
Discussion Starter #7
Eagle eye,
I did indeed have the machine shop do you the heads. I pretty much replaced all gaskets and seals that I could without tearing the block apart.

Seagrass,

Thank you for your replies! I did investigate the PCV valve, the PC valve was changed when I did the job. However the hose that comes off of it is old and hard. There’s a bit of a split where it meets the valve. I’m going to order a new one and get it installed for the time being, I have wrapped in duct tape to keep it together and use the zip tie just to try to minimize vacuum losses.
More worrisome however is the stream sounds the gearbox is making. It’s a five speed manual, there has been much work done prior to me buying the car. And tearing it apart the clutch components look new and there was no need to resurface the flywheel. It’s a strange noise I believe on the input shaft. It is a rotating noise that disappears when I push the clutch in without the car being in gear.

Oh what fun! ?

MacDad
 

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'98 white GT wagon, '99 red GT wagon, '06 Outback wagon (green)
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9 Posts
Discussion Starter #8
Eagle eye,
I did indeed have the machine shop do you the heads. I pretty much replaced all gaskets and seals that I could without tearing the block apart.

Seagrass
 

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'98 white GT wagon, '99 red GT wagon, '06 Outback wagon (green)
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Discussion Starter #9
OK,

So I have checked the patency of the PCV valve hoses, I replaced the PCV valve to manifold hose, but I’m still having highly excessive oil consumption. I’ve used UV dye as I mentioned before and I cannot find an actual substantial leak. I’m gonna have to go with the valve stem seals.

The heads were missing in the properly before I reinstalled everything, I know I’ll have to use new head gaskets when I do the job. Do I need to be particularly careful reviewing
 

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'98 white GT wagon, '99 red GT wagon, '06 Outback wagon (green)
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9 Posts
Discussion Starter #10
Also, I know since this is a variable intake cam engine, there’s a bunch of witchcraft that I don’t have the tools to disassemble on the top portion of the head. There are multiple torques fasteners that keep the camshaft secured that’s underneath all of the belt training gear. Can I simply remove those fasteners and separate the upper portion of the head all in one piece from the rest of the head? That way I should be easily able to access the valves in the seals. Thank you guys so much for your help!

MacDad
 

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2013 2.5i Limited, Special Appearance Package, Brilliant Brown Pearl, Saddle Brown Leather, HK Audio, Moonroof, Navigation
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212 Posts
Its been at least 5 years since I have jumped on this forum but curious who has had a small block/gasket replacement and seen the oil consumption go away? I have 6 months of my 7/100 warranty left, have 67,500 on my 2013 2.5 Limited, and burning about a quart ever 2500 miles since day 1.
 

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2010 Outback 3.6R 2014 Legacy 2.5i 2003 Legacy L special edition (retired to backup)
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686 Posts
oil consumption may go away if it was being caused by worn valve guides... if your piston rings are worn, then no a head job will not fix that.
 
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