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Old 05-01-2020, 11:05 PM   #1
joea99
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Location: Stone Ridge, NY 12484
Default 2006 forester 2.5 non Turbo 5 speed

I posted about what appears to be excess oil consumption. Several quarts between changes. 176,000. Great shape otherwise.

Looking to get an idea of the best path forward should major work be required.

Simple head gasket, valve job w/seals, pistons and ring, or more, up to a complete reqbuild or short block?

Just looking for paths forward. Is this a feasible rebuild for a competent back yard mechanic, or are there secret pitfalls for those new to Subaru engines?
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Old 05-07-2020, 12:12 PM   #2
Elbert Bass
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Quote:
Originally Posted by joea99 View Post
I posted about what appears to be excess oil consumption. Several quarts between changes. 176,000. Great shape otherwise.

Looking to get an idea of the best path forward should major work be required.

Simple head gasket, valve job w/seals, pistons and ring, or more, up to a complete reqbuild or short block?

Just looking for paths forward. Is this a feasible rebuild for a competent back yard mechanic, or are there secret pitfalls for those new to Subaru engines?
So you have confirmed it is not leaking? That the PCV system is not clogged/damaged? A cylinder leakage test confirms you have excess blow-by? A vacuum gauge shows excess valve/guide wear?
If you have not diagnosed the cause then no, I would say you should not attempt the repair. The first step is proper diagnosis.

I say this only because an N/A EJ25 in great shape, even at that mileage, usually does not require that level of repair unless neglected or repeatedly overheated.
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Old 05-07-2020, 12:38 PM   #3
joea99
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Originally Posted by Elbert Bass View Post
So you have confirmed it is not leaking? That the PCV system is not clogged/damaged? A cylinder leakage test confirms you have excess blow-by? A vacuum gauge shows excess valve/guide wear?
If you have not diagnosed the cause then no, I would say you should not attempt the repair. The first step is proper diagnosis.

I say this only because an N/A EJ25 in great shape, even at that mileage, usually does not require that level of repair unless neglected or repeatedly overheated.
Thanks for your feedback.

I have only done a visual inspection of the underside and that was a while ago.

Do plan to change out the PCV valve when I can get access to the vehicle for a day.

The other tests I will have to look into doing as I am not familiar with doing them on a Subaru. Probably not too different, but not being a day to day mechanic, some research is called for. I do have the tools, but not the experience with this configuration.
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Old 05-07-2020, 01:38 PM   #4
joea99
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Originally Posted by joea99 View Post
Thanks for your feedback.

I have only done a visual inspection of the underside and that was a while ago.

Do plan to change out the PCV valve when I can get access to the vehicle for a day.

The other tests I will have to look into doing as I am not familiar with doing them on a Subaru. Probably not too different, but not being a day to day mechanic, some research is called for. I do have the tools, but not the experience with this configuration.
So, I have done some searching and found nothing about vacuum tests for valve guide wear.

Perhaps you can give me some pointers?
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Old 05-10-2020, 12:59 PM   #5
Elbert Bass
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Originally Posted by joea99 View Post
So, I have done some searching and found nothing about vacuum tests for valve guide wear.

Perhaps you can give me some pointers?
Worn valve guides (and other mechanical issues) can sometimes affect engine vacuum. It helps if you have been using a vacuum gauge for a while and are familiar with what is considered OK and not. Also Turbo engine behavior is a bit different.

Here's a quick chart to get you started:
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Old 05-10-2020, 01:24 PM   #6
joea99
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Originally Posted by Elbert Bass View Post
Worn valve guides (and other mechanical issues) can sometimes affect engine vacuum. It helps if you have been using a vacuum gauge for a while and are familiar with what is considered OK and not. Also Turbo engine behavior is a bit different.

Here's a quick chart to get you started:
. . .
Thanks for that. No Turbo, so no problem there, but the reference to carb being out of adjustment, right at the last, makes me wonder home applicable this is to "new era" engines. . . .

Anyway, soon as I can, I will figure out where my vacuum gage is, or buy a new one, and give this a go.
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Old 07-14-2020, 03:31 PM   #7
teahead
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NO severe leaks on the outside? It's burning the oil?
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Old 07-18-2020, 11:34 AM   #8
serrilion
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I think what Bass is trying to get at is over time the intake valves will have build up on them from carbon and other deposits the PVC drops back in our intake to be re-burned. When the valves are no longer sealing right due to the carbon build up or the guilds are worn out, it allows oil to leak by into the combustion chamber. A vac test will confirm the valves are in proper working order and are sealing right for if they are not your problem could be with your heads and not the piston rings.

Intake valves are normally the problem as most engines do not get hot enough to burn off the carbon build up on them. exhaust valves how ever can see acquitted temperatures to burn off the carbon deposits if run for long enough.

One other thing you can do is if you have a bore snake with a camera, remove spark plugs and look into the cylinder and look for oil sitting on top of the piston. I picked up one cheap at lowes for like $80 bucks back in the day.

Hope this helps
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Old 07-18-2020, 12:43 PM   #9
joea99
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Originally Posted by serrilion View Post
I think what Bass is trying to get at is over time the intake valves will have build up on them from carbon and other deposits the PVC drops back in our intake to be re-burned. When the valves are no longer sealing right due to the carbon build up or the guilds are worn out, it allows oil to leak by into the combustion chamber. A vac test will confirm the valves are in proper working order and are sealing right for if they are not your problem could be with your heads and not the piston rings.

Intake valves are normally the problem as most engines do not get hot enough to burn off the carbon build up on them. exhaust valves how ever can see acquitted temperatures to burn off the carbon deposits if run for long enough.

One other thing you can do is if you have a bore snake with a camera, remove spark plugs and look into the cylinder and look for oil sitting on top of the piston. I picked up one cheap at lowes for like $80 bucks back in the day.

Hope this helps
Thanks for the nudge.

I do not have a usable vacuum gauge at the moment, but can get one. Just realized I have no idea where to hook it up for the test, but can probably find that somewhere.

I do have a couple of those el-cheapo "bore scope" snakes that plug into phone or tablet via USB. I can give that a try as well.
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Old 07-18-2020, 06:18 PM   #10
serrilion
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Your welcome, The vacuum system on the subaru is very basic for our non turbo engines. It runs under the intake manifold along the bottom down by the fuel injectors, should be a valve with a wire going to it on the pass side behind the PS pump, then they continue to the drivers side again down by fuel injectors and the very bottom small line with fuel lines. The break booster obviously connects to the intake manifold ect ect same with PCV valve from motor. Only 2 hoses that will not give you any readings are the valve cover ones venting to the intake box.

You El- Cheapo bore scope, thank you for the word, I was hung over this morning, will work, I use it mostly on small engine repairs but it has come in handy for the older EJ251's and earlier DOHC 2.5's with known head gasket issues. Hope you find your answer
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