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2006 Outback 2.5i manual
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Discussion Starter #1 (Edited)
So, I posted this in my build thread; but, not many people seem to respond on it so I figured I may have more exposure here.

Problem: I have a 2006 Outback 2.5 (manual) that just started losing oil. I've lost ~1.75 quarts after almost 1,000 miles. No signs of leaking, no smoke, coolant looks great. I assume it's my oil control rings. I should be able to reduce consumption by running a heavier weight oil; but, I plan to fix it.

I'm debating on if I should rebuild the engine myself (I've rebuilt a number of Honda engines myself, I have a great machine shop for the machining portions, but never a Subaru). I also am considering just swapping in a JDM EJ253 equivalent. Of course I'd replace headgaskets and other seals before install.

I've watched a couple videos on rebuilding the SOHC EJ's, and there are certainly a few unique things to consider. Even so, the process still appears the same as other builds I've done, minus said unique attributes related to having the block be in two halves. Even so, rebuilding is always stressful for me, and it is overall a VERY tedious process.

The JDM swap, on the other hand, also carries risk. I did a JDM swap once on a previous project car (a Honda) and the engine I received was missing parts (the distributor) and had water and significant rust in one of the cylinders. Despite trying to work with the place I bought it from (they were useless) I ended up rebuilding the entire engine myself anyway. I worry the same thing could happen here. Also, would this be a direct swap? As in, does the USDM engine harness plug right in to all the connections on the JDM engine?

For what it's worth, this is the place I was looking at for the JDM replacement....



Lastly, I found a site that says they specialize in rebuild Subaru engines, and they sell them with the block and heads. Same price as the JDM engines, but there is a $500 core charge. I'd just have to swap over all my supporting hardware from my engine. Not too bad.

This is them. Anybody have experience with them?




Appreciate you looking!
 

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How many miles? Are you leaking oil?
 

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2006 Outback 2.5i manual
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Discussion Starter #3
How many miles? Are you leaking oil?

Engine supposedly has about 110,000 miles on it (was swapped due to blown original engine, chassis has 187,000). As stated above, no evidence of leaking, no evidence of oil/water mixing, no smoke out of tailpipe. I've thoroughly inspected the engine to look for evidence of causes for my oil loss. PCV valve is new (no way I'd lose this much oil this fast if it wasn't working properly, though). I'm positive it's the oil control rings. Unlikely to be anything else.
 

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if you pull a front o2 sensor out do you get oil on you finger ?
 

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Discussion Starter #5 (Edited)
if you pull a front o2 sensor out do you get oil on you finger ?
Sensors are high and dry, along with the entirety of the exhaust manifold (inside and outside).

Edit: picture of the primary a/f ratio sensor.

506425



Also, a video of the exhaust when running... No smoke.

 

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One, the JDM supplier in Orlando has had good engines for me and my customers in the past.

Two, avoid that engine builder unless you want to go over every bolt on the engine. Don't pay a core charge to anyone. If they want the engine back, they can pay for return shipping. If it's that important to them, they'll cover shipping the engine core.

Three, that AF sensor is not showing signs of oil being burned. It looks normal. It would be loaded with carbon if oil was being burned. No oil in the pipes is another indication the oil isn't going out the pipes.

Does it smoke on cold start up? Or not at all?

Have you done a compression test?

Can you look inside the throat behind the throttle body and see how wet it is?

If I understand it, there is absolutely no oil on the engine, trans, or undercarriage?

How are you checking the level?
Here's the process - Start the car and idle for a minute, shut off, wait 5 minutes, check the oil level. Top mark is full, bottom mark is 1 qt low.

Another thing you can look at is the STFT. At idle and cruising, if there is a lot of carbon from burning oil in combustion, the AF will report a low amount of oxygen and the ECM will add fuel resulting in a mostly positive fuel trim. At highway cruising speed it won't be noticed much because the oil will burn in combustion.

If you want to clean the rings because you believe the oil ring is not doing it's job, run full conventional oil in it a couple oil changes, not blended or full synthetic. You can also run a Sea Foam engine flush on it which will remove majority of the carbon in the oil system. (Sea Foam flush is poor in 5 oz and drive the car normal for the last 500 miles prior to an oil change.)
 

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And I forgot, If you use a JDM engine, all you have to do is use your intake manifold and harness. Everything plugs up the same. The AC compressors on JDM engines are different, so if it's got a compressor on it, ditch it. It's no good in the US.
 

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Pop the timing cover off and see if your leaking oil out of one of the cam seals. If there is no oil in the exhaust, that would eliminate oil control rings. Oil has to be going somewhere. Maybe it's building up in the timing cover and hasn't started to leak out yet.
 

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Discussion Starter #9
@cardoc - Much appreciated about both the JDM engine supplier info, and the enginesus.com reputation! As for the rest, I'll try to go through each of your points, individually to make sure I don't miss anything.





Does it smoke on cold start up? Or not at all?
The video posted above is my engine during cold-start up. No visible smoke during idle or revving. It does not smoke when it's warm, either.



Have you done a compression test?
I have not, though I'm considering doing it this weekend. If so, I'll post the results.


Can you look inside the throat behind the throttle body and see how wet it is?
I have not done that. I should be able to take a look and get some pictures over the next day or so. I'll post here.


If I understand it, there is absolutely no oil on the engine, trans, or undercarriage?
Correct. Everything under and around the engine is very very dry. No signs of oil leakage.


How are you checking the level?
Here's the process - Start the car and idle for a minute, shut off, wait 5 minutes, check the oil level. Top mark is full, bottom mark is 1 qt low.
I usually check it when the engine is cold, after it's been sitting all night. No oil was even visible on the dipstick this last time I checked. Added 2 quarts to bring it up to a normal level (in-between the two holes).



Another thing you can look at is the STFT. At idle and cruising, if there is a lot of carbon from burning oil in combustion, the AF will report a low amount of oxygen and the ECM will add fuel resulting in a mostly positive fuel trim. At highway cruising speed it won't be noticed much because the oil will burn in combustion.
I only have FreeSSM. I'm not sure if it has access to the fuel trim readings... Maybe it does, though.



If you want to clean the rings because you believe the oil ring is not doing it's job, run full conventional oil in it a couple oil changes, not blended or full synthetic. You can also run a Sea Foam engine flush on it which will remove majority of the carbon in the oil system. (Sea Foam flush is poor in 5 oz and drive the car normal for the last 500 miles prior to an oil change.)

This sounds like a good idea to me. I appreciate your response (and everyone else's so far). I'll post back when I have updates.
 

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Discussion Starter #10
Pop the timing cover off and see if your leaking oil out of one of the cam seals. If there is no oil in the exhaust, that would eliminate oil control rings. Oil has to be going somewhere. Maybe it's building up in the timing cover and hasn't started to leak out yet.

Good idea. I didn't see any evidence of leakage around the timing belt cover, but I would be an easy check. I recently replaced my timing belt and when I did that everything looked great.
 

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Everything under and around the engine is very very dry. No signs of oil leakage.
When checking the engine for signs of leaking, were the top, and backs of the heads examined? Especially on the right (passenger side) head, oil could be leaking at the AVLS control devices at the back, running down, dripping onto the hot exhaust below and disappearing.
 

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Discussion Starter #12
When checking the engine for signs of leaking, were the top, and backs of the heads examined? Especially on the right (passenger side) head, oil could be leaking at the AVLS control devices at the back, running down, dripping onto the hot exhaust below and disappearing.
I didn't notice anything in particular. But, I'll take a closer look again and report back.
 

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Another thing you can look at is the STFT. At idle and cruising, if there is a lot of carbon from burning oil in combustion, the AF will report a low amount of oxygen and the ECM will add fuel resulting in a mostly positive fuel trim. At highway cruising speed it won't be noticed much because the oil will burn in combustion.

Post 6 should say, the ECM will reduce fuel because the oil deposits in the exhaust will lower the oxygen. Low oxygen means reduce fuel. Reduction in STFT would be on the high side and the engine would essentially run leaner than it should.
 

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Discussion Starter #14
When checking the engine for signs of leaking, were the top, and backs of the heads examined? Especially on the right (passenger side) head, oil could be leaking at the AVLS control devices at the back, running down, dripping onto the hot exhaust below and disappearing.
So, I took a closer look all around and again on the back of the driver's side and passenger's side heads. Didn't notice anything very significant....until I looked closely at the pictures I snapped while doing so.

Specifically in the passenger side, like you mentioned, around the AVLS solenoid and the rear camshaft seal.

Take a look...

506481


506482



Fresh oil on these spots. But I'm not really seeing much around it, which might make sense, as it would only be leaking while the oil is pressurized (ie engine running).

But would this account for the significant oil loss I'm seeing? What do you guys think?

Also, I peeked in the driver's side portion of the timing belt cover. Dry as a bone. I'll sneak a peek under the passenger side cover later.


Appreciate all the input so far.
 

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The oil on the cam shaft seal and then above it at the ALVS solenoid mount could be coming from above; look at the solenoid and the pressure switch, which tends to develop leaks (quite a few cases here). Both should be oil free. If there's leakage, the oil might be seeping down the back where you saw it on the bolt and below. There have also been cases of the gasket at the solenoid mount developing leaks.



When the pressure switch develops a leak, it will actually allow oil to pass only when the car is being driven and the engine is running at more than, roughly, 1600 rpm. That's because the switch is in the line between the AVLS solenoid and the camshaft mechanism. The pressure there is high only when the ECM sets the intake valve lift to the high position.

Also, but tangential, those dark spots on the back of the head are usually caused by the grease in the axle CV joint spraying out through a crack in the rubber boot.
 

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Along with pressure, the AVLS system using a high volume of flow. So a large quantity of oil loss would be expected with a leak of this nature.
 

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Is there oil on the top of the engine under the intake manifold? There is a small rubber hose that is known to get brittle with time on to of the engine. My mechanic says they go bad and leak a fair amount before it shows on the bottom of the car.
 

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Discussion Starter #18
The oil on the cam shaft seal and then above it at the ALVS solenoid mount could be coming from above; look at the solenoid and the pressure switch, which tends to develop leaks (quite a few cases here). Both should be oil free. If there's leakage, the oil might be seeping down the back where you saw it on the bolt and below. There have also been cases of the gasket at the solenoid mount developing leaks.



When the pressure switch develops a leak, it will actually allow oil to pass only when the car is being driven and the engine is running at more than, roughly, 1600 rpm. That's because the switch is in the line between the AVLS solenoid and the camshaft mechanism. The pressure there is high only when the ECM sets the intake valve lift to the high position.

Also, but tangential, those dark spots on the back of the head are usually caused by the grease in the axle CV joint spraying out through a crack in the rubber boot.
Along with pressure, the AVLS system using a high volume of flow. So a large quantity of oil loss would be expected with a leak of this nature.

Makes perfect sense. In fact, after my last oil change I've been driving in much higher RPM's than usual. I've most likely been in the high cam lift profile much more than previously.

Either way, it's definitely worth replacing the gaskets. Speaking which, I found the OEM gasket for the solenoid holder, but I can't find the official o-ring for the solenoid itself. I assume I could just find a generic o-ring at AutoZone or something.

I really appreciate the info, everyone. Thank you for taking the time to read through my thread. I'll order the gasket, replace the solenoid o-ring, then monitor the oil level. I'll also take a look in and under the intake manifold to see if there's any oil to be found.
 

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It won't be an o-ring. The solenoid mount uses a metal gasket. Follow torque spec. The solenoid o-rings will be fine, just coat with oil prior to reinstalling it.

The cam end cap should be replaced as well. Since there's no oil on top of the seal area, lots on the bottom, that is a minor leak. You can clean the head up after you replace the actuator mount gasket and monitor it. It's a chore to replace that cap with the engine in the car, but it can be done.
 

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Discussion Starter #20
The cam end cap should be replaced as well. Since there's no oil on top of the seal area, lots on the bottom, that is a minor leak. You can clean the head up after you replace the actuator mount gasket and monitor it. It's a chore to replace that cap with the engine in the car, but it can be done.
Any tips on the removal and reinstall of the cap?
 
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