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07 OBXT
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Discussion Starter #1
I'd like to take precautionary measures that can extend the longevity of my car without doing upgrades that require it to be tuned. I have a pretty stock 2007 outback xt (110k) 5eat besides a borla CBE, cobb CP, grimmspeed AOS. My radiator cracked causing head gasket failure @ 98k. I had the headgasket, radiator, water pump, timing belt, motor mounts, 5eat bushing replaced at that time. 500 miles later I also chose to remove the power-parts (dp, big tmic, copp ap protune).

Since the car over heating I noticed as though the performance of the turbo was hindered some what - thus my reason for removing the parts that required a tune I felt as though there wasn't a need to squeeze more power than it came from the factory with if the turbo may be tainted. The mechanic who did the work at 101k said the turbo looked okay, but agreed with my choice of downgrading.

Not long after this I was visiting a mechanic friend and he stated that my car seems to have more blow-by than typical, also noted it's burning bit more oil than it should roughly 2qt after 1250 miles. The turbo was replaced at 73k but due to ripped inlet hose (bought @ 74.5k) was again replaced at 77k. He noted I should check the oil every time I get gas and top it up as needed.

With the knowledge that my car is consuming more oil than normal per-say, what would be the places I should look into for a cause or the precautionary measures I should take to extend the life of my engine. I don't get staining on my driveway so I don't see it being a leak, nor do I smell burning oil or see any leakage from the turbo area. Would upgrading to a killer b pickup and baffle as though help alleviate this issue?
 

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OBW H6 VDC, Tribeca, XT6
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Verify all your hoses and fittings are good and change the PCV valve.
Keep the oil topped up with synthetic oil, change it frequently, and use proper gas, that's about all you can do.
Any signs of issues - turn the car off immediately.

I don't do turbo's, but usually this is piston ring blow by due to compromised oil. Often it's not frequent enough oil changes or using conventional instead of synthetic, particularly with the unforgiving turbo engines.

In this case, prior overheating and low oil could have also contributed as this overheats the oil. These scenarios are worse when combined with conventional oil.

A repair is probably to re-ring the block (highly unlikely and possibly not even a good idea $$$$).
 

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2016 3.6 Limited with ES
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Since I've owned it March 2013 it has always gotten synthetic every 2.5-3k
Syn oil at that frequency, assuming conventional oil meets the specs, is really a ginormous waste of money.

Syn oil will easy peasy go 6k, 8k without a wimper and 10k is well within the range of any EP oil available at Walmart. There's no great good that's being accomplished at your interval.
 

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03 H6 OBW & 06 WRX Sportwagon
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I think AOSes are sometimes confusing to install - that system needs to be checked out.
 

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OBW H6 VDC, Tribeca, XT6
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Since I've owned it March 2013 it has always gotten synthetic every 2.5-3k
nice work. keep it up.

some (all?) EJ25 turbo's have a screen in the oil feed line - i would be sure to replace, clean, or otherwise address that screen as well.
 

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02 Pair: 3.0 VDC Wag & 2.5 Limited Sedan
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updated thread title.

in the future always include XT in your threads about this engine. ...such brings more turbo owners that have it to actually read the thread and comment how they have existed owning such maint. intensive beasts.
 

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07 OBXT
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Discussion Starter #9
Verify all your hoses and fittings are good and change the PCV valve.
Keep the oil topped up with synthetic oil, change it frequently, and use proper gas, that's about all you can do.
Any signs of issues - turn the car off immediately.

I don't do turbo's, but usually this is piston ring blow by due to compromised oil. Often it's not frequent enough oil changes or using conventional instead of synthetic, particularly with the unforgiving turbo engines.

In this case, prior overheating and low oil could have also contributed as this overheats the oil. These scenarios are worse when combined with conventional oil.

A repair is probably to re-ring the block (highly unlikely and possibly not even a good idea $$$$).
@95k the pvc valve was replaced when I had the Grimmspeed air oil seperator added. Since I've owned the car it's had synthetic changes usually 2.5k but at most 3k, I always use premium and try not to let the needle go past a 1/4 tank.

The previous owner did f-me over some, besides not mentioning the torn inlet resulting in having to replace the turbo soon after purchase. They had maintenance history of the car which I reviewed upon first seeing it, however upon picking up the car for purchase (out of state) they noted it'd be in the glovebox - didn't think to check till I was home, no records. They kept saying they'd mail me it... never happened. Had the transmission system flushed soon after, dealer noted it really needed it and looked to never been done before. That said I wouldn't be surprised if they lied about how the car was treated...

So with that - besides being OCD about the oil level, an replacing the pvc vavle again. The issue is related to the piston rings allowing oil to bypass them? I am to understand its not a problem with oil pressure or oil sloshing around in the pan - the pickup and baffle aren't really something to consider as a precautionary measure for the car consuming oil.... Rather means to continuing the supply of oil, but if there's not enough oil (not checking the level) the pick and baffle aren't going to help me anyways?

Bit more info - in the cold temps of below freezing the car will sometimes showcase piston slap sound - mechanic states its not something I should fret about. Is that a normal thing - as the car's operating temp takes longer to get up? Or could this be another sign to the re-ringing of the block - $$$$ which maybe better spent on a new block or good used block or just cut all loses and if that time comes just move forward with another car.


Syn oil at that frequency, assuming conventional oil meets the specs, is really a ginormous waste of money.

Syn oil will easy peasy go 6k, 8k without a wimper and 10k is well within the range of any EP oil available at Walmart. There's no great good that's being accomplished at your interval.
I've heard so many different opinions on this regard, the first few were done at the dealer who'd put a sticker for 6k notices - while chatting with a tech who works at that the same dealer stated they change their wrx's oil every 2750 mi. I've been told every 8k is fine if you're totally stock, but then again I'm not so it's dam confusing. If my wasted money prolongs the life of my car's life for another 3-4 years costing me roughly $700 that's a cost I'm okay with.


I think AOSes are sometimes confusing to install - that system needs to be checked out.
I will check into it, I do know of the two people I let work on my car the first one didn't understand how it works. While the second one had no issue - working on a number of modded wrx/sti's.

nice work. keep it up.

some (all?) EJ25 turbo's have a screen in the oil feed line - i would be sure to replace, clean, or otherwise address that screen as well.
The turbo that is in the car currently has had the screens removed to prevent clogging.

updated thread title.

in the future always include XT in your threads about this engine. ...such brings more turbo owners that have it to actually read the thread and comment how they have existed owning such maint. intensive beasts.
Note taken. Thank you for the updated title.
 

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OBW H6 VDC, Tribeca, XT6
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The issue is related to the piston rings allowing oil to bypass them?
I have limited and anecdotal block experience and not with turbos' - but based superior subie and import owner and some others have said - I think that's what happens. They re-rings a lot of subaru blocks.

Bit more info - in the cold temps of below freezing the car will sometimes showcase piston slap sound
Piston slap is benign. If that's what it is - verify and you don't sound inclined to repair it so ignore it.

Knurling the pistons or I think Subaru has in the past offered replacement pistons that mitigate the issue somewhat...if you needed stuff to look into or ask about, again I have limited experience and zero with turbo's.
 

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03 H6 OBW & 06 WRX Sportwagon
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weak timing belt tensioner might mimic piston slap.
 

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07 OBXT
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Discussion Starter #12
Piston slap is benign. If that's what it is - verify and you don't sound inclined to repair it so ignore it.

Knurling the pistons or I think Subaru has in the past offered replacement pistons that mitigate the issue somewhat...if you needed stuff to look into or ask about, again I have limited experience and zero with turbo's.
From what I recall reading a couple years ago on NASIOC (1st noticed winter 14/15 @ aprox 88k) it's not uncommon for it to happen especially in the cold - an couple owners noted that even after re-ringed the slap noise appeared later again. With that information - yes it doesn't really make me inclined to have it done if it's going to come back again.

Now if re-ringing the pistons would subside the blow-by issue and oil consumption I'm dealing with then I'd have a different opinion - but I need more knowledge on the topic before I can come to that decision.

Thanks
 

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Master Caster
2005 XT, Mildly Modified...2006 XT Limited, Highly Modifed
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Get a compression test and post numbers.

I have done better by changing tp 10w-40 syth pil in my one car that is a user.

The GS AOS, is it the oil cap AOS. That unit does very little if nothing.
 

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OBW H6 VDC, Tribeca, XT6
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General Disorder, Gloyale, and Ivansimports are business owners, subaru specialists, highly technically and experientially versed in these engines and their precise failure modes. they are who I'd take my head nods from regarding reringing. They discuss this some over on ultimate subaru message board.

Piston slap in NA engines is solved via knurling or replacing with updated pistons available for some EJ25's.

here's a comment - i didn't really read through this or have seen it before but just a quick google search for superior subie and import which is owned by General DisorderL

https://www.hirerush.com/service/piston-skirt-knurling--subaru-piston-slap-repair--100_i43203

piston slap - 1990 to Present Legacy, Impreza, Outback, Forester, Baja, WRX&WrxSTI, SVX - Ultimate Subaru Message Board
 
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