Subaru Outback Forums banner

1 - 20 of 29 Posts

·
Registered
Lawn ornament XT
Joined
·
14,366 Posts
Discussion Starter #1
Hi fellow XT owners!

The past few weeks have seen a few members suffer some pretty severe mechanical failures on their cars. A few examples:

"Gutless" - Oil loss leading to total powerplant destruction, inadequate warning to the driver
"$8,000" - Very expensive engine repair in a 2006 XT (exact failure unknown)

As I write this post, the newest XT on earth left the factory 4 years ago. The oldest ones are over 9 years old. All cars tend to deteriorate with age, and a finicky, high-powered, mod-friendly car like an XT is bound to have more than a normal share of trouble as time goes by.

Prices on these vehicles will continue to fall as they age, but the cost of repair after a catastrophic failure is going up. At some point we're going to see a post that says:

"Hi guys I got my license yesterday and bought this awesome XT today, so fast and only $1500!!! BTW does anyone know what P0011 means??"
I wanted to get this thread started with a few specific goals in mind:

• Basic information for new owners of old XTs

• A discussion of modifications to increase reliability and longevity- this might just be a recap or link list since a lot of that has already occurred in other threads.

• I'd very much like to get a discussion going on the idea of adding extra instrumentation for the sake of identifying an engine problem more quickly and accurately- before it becomes a four-figure nightmare bill.

The folks over at LegacyGT.com have written a very good wiki page to help owners who have already suffered a turbo failure. I see no need to duplicate their work here, so rather I want to focus on ways to prevent such a failure in the first place.

Regarding instrumentation, I've looked at this a few different ways:

• Sampling oil pressure from more than one location. I don't think an ordinary oil pressure gauge is going to be a good enough indication, because the turbo and AVCS systems are on a branch circuit.

• Sampling CHRA bearing block temperature, or CHRA water block outlet temp to keep an eye on the turbo bearing itself.

• Modifying the ECU to trigger a Check Engine light based on data sampled from aftermarket supplementary sensors like the above. There's already been a suggestion to go even further and figure out a way to cut the ignition when a turbo failure is somehow sensed or predicted.
 

·
Registered
Lawn ornament XT
Joined
·
14,366 Posts
Discussion Starter #4
***THIS POST IS A WORK IN PROGRESS UNTIL I REMOVE THIS LINE!***
I encourage you to PM me if you think there is something to add or change in what you see here.

I've spent a few hours researching the idea of adding a useful gauge to help warn of impending turbo failure while there's still time to do something about it.

Over the course of a few posts to Jefferson's thread I started thinking about developing a cost-effective method for predicting and preventing the most expensive types of failures encountered by XT owners.

I don't have enough data to sort these by frequency, so this is sort of random. However, I feel that this list represents the most common causes for very expensive repairs on XT engines.

I. Turbo failure due to oil starvation
A. Blocked banjo bolt filter prevents oil flow
1. Oil change interval too high- once the oil filter is in bypass most of the time, the banjo bolt screen is fouled and blocked causing starvation at the turbo bearing.

2. Oil type incorrect- natural petroleum blends coke at lower temperatures than synthetic, causing more pollution in the oil which overwhelms the filter and banjo bolt screen.

3. Oil filter bypass spring: if the oil filter spends too much time in bypass, more material will collect in the banjo bolt filter which has no bypass function.

B. Oil supply failure:

1. Low oil due to incorrect oil change procedure
The XT engine (EJ255) has an oil capacity of 4.2 US quarts or 4 Liters.​

2. Oil pump failure
• Extraordinarily rare. Check everything else again.​
3. Oil sump pickup tube failure
• The oil pickup tube can crack and allow insufficient suction from the oil sump. Killer B Motorsports has developed a reinforced pickup tube to combat this problem. Thanks Imprezkid!

4. Gradual oil loss by burning oil:

a. Improper tune causing damage to exhaust valves- oil burns at the exhaust valve/valve guide interface

b. Ring/ringland failure causing oil to leak into the combustion chamber

c. Turbo bearing leak into exhaust

d. Turbo bearing leak into intake

e. PCV Valve normal function passing oil vapor to the intake

f. PCV Valve abnormal function passing too much oil into the intake


Looking over the above list, there is a fairly wide variety of situations which can cause catastrophic engine failure in these cars. To come up with a means for detecting imminent turbine failure across all of them, we would have to rely on a very common data point.

Initially I considered the idea of monitoring oil pressure. However, I had to consider the idea that the turbo is fed via an external branch from the main pressurized oil circuit. This means that in some conditions, a failure in the branch circuit might not register properly on a gauge or sensor connected to the main circuit.

From there, I thought about looking specifically at oil flow properties through the branch circuit alone. I discovered that there are various flow sensors which might be appropriate for the task. I haven't found one which looks like it would be easy to monitor from the cabin, however.

After that, I started thinking about monitoring the water temperature coming from the turbo center housing rotating assembly (CHRA) water block. The idea is that we could look for an unusually high bearing temperature. A high relative bearing temperature is a nearly universal method of detecting trouble in a rotating device.

From there, I looked into the idea of adding a temperature probe to the coolant outlet on the turbo water block. The Turbo Water Outlet Temp (TWOT, rhymes with "toot" ok? ...OK?) measurement might be the simplest, cheapest-to-implement warning device for the truly paranoid XT owner. I think every problem in the list of causes at the top of this post would cause TWOT values to rise.

From there, I looked into the idea of a proper gauge to monitor this temperature. The PLX FT sampler can read an ordinary fluid temp probe and encode the result in a serial data stream. From there, the data can be displayed on one of several video virtual gauge heads also sold by PLX. Several of these devices allow a programmable alarm if any particular condition is met or exceeded.


Pile of bookmarks that I will eventually develop into a useful post:


a complete guide to hacking your vehicle bus on the cheap & easy – part 1 (hardware interface) | theksmith

http://elmelectronics.com/ELM327/AT_Commands.pdf
 

·
Registered
Car: 2008 Tribeca, 2010 LGT, Sold: 2005 XT Limited
Joined
·
2,926 Posts
This is a good thread. There is a thread over at legacygt.com talking about reliability mods: http://legacygt.com/forums/showthread.php/reliability-modifications-178342.html?t=178342&highlight=reliability+mod

Also should mention the TMIC failure and how to fix it (bullet proof kits over at legacygt.com). http://legacygt.com/forums/showthread.php/bulletproof-tmic-mod-lgt-08-wrx-158870.html

I don't ever hear anyone talk about that over here.

I think it is a good idea to mention these resources, since I think few new XT owners realized the GT world is the same.

And I wouldn't sweat the new failures we are seeing here. It's not long time members, but new folks finding their way here.

122k on original turbo. All I've done is change the banjo bolt filter. I was even doing the 7.5k oil change until 2010 or so.
 

·
Registered
2008 OBXT
Joined
·
26 Posts
Most say remove the banjo bolt filter all together, also idk if it applies to obxt's (ej255) but there are also oil pickup tube failures. New tubes or killer B parts can fix this. Owners need to know that they can look at multiple boards to get engine info. Ej255 (lgt,wrx,fxt, and obxt) & ej257 found in sti's are the same longblock for the most part minus the dual avcs found in 08+ sti's. I recently bought a obxt with a bearing failure, the owner didn't know or failed to address the issue till they manage to ruin the whole longblock.
 

·
Premium Member
2001 VDC/SC One of a Kind
Joined
·
14,020 Posts
Oil temperature is also a factor. If the oil cannot dissipate heat along with providing lubrication, you get a gradual rise in heat up to the point the bearing heat will increase the oil temperature. This is one of the ways the unit fails with low oil. The oil is circulated so fast it does not have time to cool in the pan.

Varying climates have an effect on oil temperature, so a primary temperature base would need to be verified in order to judge the outlet temperature, or incorporate 2 sensors for inlet and outlet which would work in any climate.

Adding an additional oil cooler will also help provide enough oil temperature control and is a low cost supplement. Of course tuners have been using these for years.

Subaru WRX/STI Oil Cooler Kit, 2006-2007, by Mishimoto


EGT sensors would also relay good data, but by the time the EGT reaches the threshold, you'd be looking at a Turbo rebuild and possibly CATs, but it may save the engine if caught early enough.
 

·
Registered
Lawn ornament XT
Joined
·
14,366 Posts
Discussion Starter #8
Varying climates have an effect on oil temperature, so a primary temperature base would need to be verified in order to judge the outlet temperature, or incorporate 2 sensors for inlet and outlet which would work in any climate.
I've been focusing my research on this. I talked to the tech guys at PLX to find out if their probes could be used to create derivative data- delta of one temp reading to another. They're looking into it.

Also I'm ignoring oil properties now for the following reasons:

• Oil starvation is the primary complaint. I can't measure the temperature of something that isn't there as a warning before it goes away.

• System design. The oil sump is at the bottom, below the turbo. The water reservoir is at the top, above the turbo. Much less likely to have the water block run dry.
 

·
Registered
Car: 2008 Tribeca, 2010 LGT, Sold: 2005 XT Limited
Joined
·
2,926 Posts
From the reading I've done, the oil pickup tube crack is rare for an XT.
 

·
Registered
05 OBXT 5eat stg1.2
Joined
·
2,105 Posts
I think you're over complicating things here. Just my opinion though.

Change the oil regularly, use good oil, and check it constantly.

Keep your gaskets in good condition.

Get rid of up pipe cat.

Check turbo for shaft play every once in a while.

Get a decent stg 1 tune, even if you cut boost back to stock.

You could go for one of the infamous oil lines if they start making them again, but changing the oil regularly should keep the banjo filter clean.

There is a common factor in most of the failures. That is not checking oil enough or slacking on OCI. As far as other issues go, most of them are tune related, hence the stg 1 recommendation.

If you want gauges, go for an oil pressure gauge, boost gauge, and AFR gauge. The boost gauge will tell you if you have a leak, as well as if the ecu is unhappy due to knock since the ecu will cut boost as a failsafe. The AFR gauge (and real AFR sensor) will tell you if there are dangerous vac leaks that are going to cause damage from lean fueling. There is also an ecu mod that will flash the CEL every time the knock sum increments if you feel like taking that on (not a simple process IIRC).
 

·
Registered
2008 OBXT
Joined
·
26 Posts
I think the biggest thing is people stepping up from N/A cars to turbo cars and not realizing how much damaged can be caused if they go low on oil, have a failure, or just don't take care of the engine, not saying it doesn't cause issues in N/A motors as well, but it sure cost a lot more when a turbo motor shreads something like a bearing
 

·
Premium Member
2001 VDC/SC One of a Kind
Joined
·
14,020 Posts
I think the biggest thing is people stepping up from N/A cars to turbo cars and not realizing how much damaged can be caused if they go low on oil, have a failure, or just don't take care of the engine, not saying it doesn't cause issues in N/A motors as well, but it sure cost a lot more when a turbo motor shreads something like a bearing
The damage is when the bearing in the turbo goes and then the compressor breaks apart sending fragments in to the engine and oil system.

Not saying running low on oil will not harm an engine bearing, it will.
 

·
Registered
Lawn ornament XT
Joined
·
14,366 Posts
Discussion Starter #14
From the reading I've done, the oil pickup tube crack is rare for an XT.
The oil pickup thing seems to be 06 specific and not very widespread.
I haven't heard of one cracking in an Outback, only in WRXes. And I haven't even heard of many of those since I don't generally pay attention to WRX stuff.
 

·
Registered
Lawn ornament XT
Joined
·
14,366 Posts
Discussion Starter #15
I think you're over complicating things here. Just my opinion though.
I'll cheerfully take that. Were I to actually build up this mod and install it on my car, I doubt it would be a big enough improvement over the status quo that anyone else would rush to follow.

But as a theoretical discussion shared with other XT owners, I'm kind of hoping to refine it into something better, cheaper and simpler.

Change the oil regularly, use good oil, and check it constantly.

Keep your gaskets in good condition.

Get rid of up pipe cat.

Check turbo for shaft play every once in a while.

Get a decent stg 1 tune, even if you cut boost back to stock.
An excellent rundown of what I referred to as the status quo- best methods for preventing & detecting catastrophic turbine failure. The only item on it I'm not familiar with is the last one. I have seen the occasional mention that the stock tune can get too lean in some conditions, but I haven't spent a lot of time reading up on it.

Anything you'd care to share or link to here?
 

·
On the Super Mod Squad
2002 Pair: 3.0 VDC Wag & 2.5 Limited Sedan
Joined
·
26,077 Posts
BIG Kahuna Rasterman

***THIS POST IS A WORK IN PROGRESS UNTIL I REMOVE THIS LINE!***
I encourage you to PM me if you think there is something to add or change in what you see here.


I just wanted to chime in and applaud the big Kahuna :D Rasterman for taking this on. Now I am going to stop typing with my naturally aspirated fingers and let all the forced induction fingers have it.

With this long distance dedication to those Ladies like the Kinks' Lola that have passed on, well loved and not forgotten.

THE KINKS - 1981 - "Destroyer"
( a live version, we want these tasty nymphomaniac supermodels to live).

THE KINKS - 1981 - "Destroyer" - YouTube

song from album:Give the people what they want! :D

Met a girl called Lola and I took her back to my place
Feelin' guilty, feelin' scared, hidden cameras everywhere
Stop! Hold on. Stay in control

Girl, I want you here with me
But I'm really not as cool as I'd like to be
'Cause there's a red, under my bed
And there's a little yellow man in my head
And there's a true blue inside of me
That keeps stoppin' me, touchin' ya, watchin' ya, lovin' ya

Paranoia, the destroyer.
Paranoia, the destroyer.

Well I fell asleep, then I woke feelin' kinda' queer
Lola looked at me and said, "ooh you look so weird."
She said, "man, there's really something wrong with you.
One day you're gonna' self-destruct.
You're up, you're down, I can't work you out
You get a good thing goin' then you blow yourself out."

Silly boy ya' self-destroyer. Silly boy ya' self-destroyer

Silly boy you got so much to live for
So much to aim for, so much to try for
You blowing it all with paranoia
You're so insecure you self-destroyer

(And it goes like this, here it goes)
Paranoia, the destroyer
(Here it goes again)
Paranoia, the destroyer

Dr. Dr. help me please, I know you'll understand
There's a time device inside of me, I'm a self-destructin' man
There's a red, under my bed
And there's a little green man in my head
And he said, "you're not goin' crazy, you're just a bit sad
'Cause there's a man in ya, knawin' ya, tearin' ya into two."

Silly boy ya' self-destroyer.
Paranoia, the destroyer

Self-destroyer, wreck your health
Destroy your friends, destroy yourself
The time device of self-destruction
Light the fuse and start eruptin'

(Yea, it goes like this, here it goes)
Paranoia, the destroyer
(Here's to paranoia)
Paranoia, the destroyer
(Hey hey, here it goes)
Paranoia, the destroyer
(And it goes like this)

Paranoia, the destroyer
(And it goes like this.)
 

·
Registered
2008 OBXT
Joined
·
26 Posts
I haven't heard of one cracking in an Outback, only in WRXes. And I haven't even heard of many of those since I don't generally pay attention to WRX stuff.
The long blocks in obxt are almost identical to wrx motors... It's definitely just something to look at, I'm definitely not risking a 3k dollar engine over that.
 

·
Registered
05 OBXT 5eat stg1.2
Joined
·
2,105 Posts
Subaru is known for having not so good stock tunes on turbo engines. The STI and LGT both suffer from it. It comes down to running more timing than they should to help with emissions. The stock maps knock more than they should. There are tons of engines with cracked ringlands and burnt valves. A lot of these are stock. A basic stg 1 tune consists of raising boost to around 16psi, leaning out the fueling slightly (still rich, just not quite as rich as stock), and dialing in timing so that everything is safe. Logging stock vs stg 1 will shock you. You'll have more power all over and much less knock.

The LGT and XT both get the occasional oil pickup tube failure. It's always the same weld that fails. Like I mentioned, it seems to be 06 specific. There is a killerB replacement option.

A local guy has a carPC with a readout of all the basics. He has afr, boost, temps, knock sum, etc. right there on the dash. Add in oil temp and pressure and you'd have the most ideal setup. Not expensive, but tons of work and you'd have to be extremely knowledgeable with computers.
 

·
Registered
'09 OBXT with SpecB 6MT/BTS-5056/DOM1.5XTR and '02 WRX w/loads of JDM parts
Joined
·
292 Posts
I just went with the STi Performance Gauge Pack which has boost, oil temp and oil pressure along with a custom tune done by GST. I could also use my AP as a gauge to read one of many parameters.
 
1 - 20 of 29 Posts
Top