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fahr_side 10-30-2011 05:54 AM

Turbo failure wiki
Blown turbo info roundup thread.

Every other day a new thread is started along the lines of ‘OMG my stock turbo died, what should I do / what went wrong?’ etc. This thread will try and answer all these questions in one place and others related to it as they come up. Hopefully it will snowball into enough info to warrant a link or mention in the sub-forum FAQ. Please feel free to add questions or answers or offer better information if you have it.

Which cars are affected?

2.5 liter turbo models with OEM single-scroll IHI turbos are seen to suffer these failures. That means 2005~2009 LGT and OXT models to those in North America. Twin-scroll models sold in other markets do not seem prone to these problems, and the 5th gen (2010~2014) models also seem to more reliable. 2007 and later models with the revised VF-46 also seem to less effected, though it’s possible less failures are seen because there are less on the road or if they have just covered less miles so the failures haven’t started yet.

Is there a recall?

There has not been a recall on the turbo, oil supply system or related hardware. Some TSBs including this one have been released which discuss the issues with banjo filters etc., OCI has been reduced since the car was launched and Subaru themselves stopped fitting the banjo filters to several models in 2008.

Can I claim it on warranty?

Varying success on this. Some have been denied. Some have had a turbo replaced. Others have had their parts provided on warranty but had to pay labor themselves. Some have had a turbo but after the engine failed were on their own. Some have had both engine and turbo replaced / overhauled on warranty. Subaru are obviously aware of the issue at some level but not every dealer is. You may want to call in an area service writer to assist. As in all powertrain warranty claims, Subaru will likely deny you cover if you have done power mods like a downpipe, intake or stage tune. Proceed with caution. YMMV.

How many fail?

Check out the very helpful survey thread. From anecdotal evidence it seems a lot, though people who go 100k without failure don’t complain about it and are less likely to post this information. Many people go to very high mileage on the stock turbo, though this is of no comfort to those whose turbos fail.
Your turbo is not guaranteed to fail. Nor is it guaranteed to go forever. A journal-bearing turbocharger is to some extent a wear item like any other on your car. How it lasts depends partly on it's design, build quality and application, and partly on how you use and maintain it.

What will happen?

Symptoms of failure.

  1. Smoke. Some owners see smoke from the exhaust before or during failure, typically there is more smoke while in boost. May or may not be accompanied by oil in the intercooler, noticeable oil consumption.
  2. Noise. Owners report squealing, screaming or howling noises from under the hood much of the time. In some cases it’s instant failure with no warning but most seem to be able to limp some distance before complete failure.
  3. Metallic particles in the oil. Very often very fine and non-magnetic, so magnetic drain plugs or magnets stuck on the oil pan may not catch this.
  4. Catastrophic turbo failure, no boost, CEL etc. Many owners report being stranded at the roadside unable to start or run the car. Very often it’s possible to run the car very gently but no boost can be obtained.
  5. Engine lubrication failure, oil contamination, catastrophic engine damage. Some owners have continued to run the car past the point where the turbo failed in order to get home or to a shop, and had the engine fail completely on the way. Usually a bearing spins, the oil pressure light comes on or some other combination of CELs occurs and the engine will no longer run or is so noisy the owner won’t run it any further.


  1. Turbo failure. Problems usually start with oil leaking into either or both the turbine and compressor housings. A leak on the exhaust side will manifest itself as a smoky exhaust and turbo wear can be confirmed by pulling the downpipe and checking for radial play on the turbine wheel. If the problem isn’t solved at this point either the bearings wear so badly that the wheels crash the housings so hard they won’t turn any longer, or the shaft itself breaks right behind the turbine wheel.
  2. Oil contamination. The failing turbo bearings produce a stream of fine particles of bearing metal and / or the turbine shaft itself introduces steel particles in the oil draining from the turbo back into the oil pan. Obviously the longer the engine is run after the symptoms begin, the more contamination will be created.
  3. Possible engine bearing failure. Oil from the pan is of course picked up by the oil pump and passed through the filter before it’s returned to the main galleries. However, oil filters do clog when overloaded with suspended particles and they have a bypass to prevent blockage from stopping the supply of oil to the galleries. Better to have dirty oil circulating than none at all. The fine particles can and will clog the oil passageways in the engine, and score bearings from mains and rod ends to camshafts. Given enough particles and time the whole engine can be rendered damaged to a point where all moving parts need replacement. The camshafts run directly in the cylinder heads with no metal bearings. Wear on the camshafts can and will damage the bearing surfaces badly enough to render the heads useless.
  4. Possible engine failure due to ingestion of compressor debris. Not sure if this has been documented but potential exists for parts of the compressor wheel to get into the cylinders.

Underlying causes

  1. Oil change interval. Subaru now recommends an OCI of 3,750 miles for all turbo models and insists on synthetic. Back in 2005 the OCI was 5,000 miles and dino oil was okay. Perhaps Subaru has increased the requirements due to all the turbo failures. Many long-term owners prefer to change oil at 3,000 miles.
  2. Oil quality. We can debate all we like on what oil is better but as long the lube meets Subaru’s specs and is changed at the recommended interval it should be sufficient.
  3. Oil filter screen in oil delivery pipe aka banjo filter. On 2005~2008 models here is a small mesh screen filter hidden away in one of the banjo fittings which supply oil to the turbo. Note that the oil supply comes out of the passenger (LHD) head oil gallery, which also supplies oil pressure to the AVCS solenoid. It is filtered oil and as such should be as clean as it gets. It seems reasonable to surmise that Subaru initially fitting a filter means there are good chances that contaminants will make it past (or around) the main oil filter. It could be they expect owners will miss an oil change or extend it so far the filter becomes clogged and bypassed. The stock banjo filter is very small in size and can easily become so clogged with debris it starves the turbo of oil. The location of the filter is so well hidden that many Subaru techs are unaware of its existence.
  4. Weak turbo design. The turbine shaft is extremely small in diameter (4mm) and there is a groove cut into it right behind where the turbine wheel is welded to the shaft, which is believed to weaken it considerably. If the shaft breaks, this is where it will happen. IHI’s bearing design is considered by many to be rather outdated, and inferior to other, newer designs. IHI themselves have several different bearing cartridges and they vary in size. The VF-40 and VF-46 use some of the smallest cartridges seen on turbos with wheels in this size range. It may be noted that ’08 WRX and ‘08~ FXT models are fitted with MHI TD04 turbos and run similar boost pressures as the LGT / OBX. Very few turbo failures have been reported on these cars.
  5. Tuning. It’s hard to tell from anecdotal evidence what percentages of failures occur on tuned cars and whether or not cause and effect can be proven. Stock boost pressure is in the range of 1 bar. Stage 1 and 2 tunes can push boost pressure up to 17psi or even higher. In order to reach these pressure ratios the turbo has to spin faster, all other factors being the same. It’s understandable that the bearings should require more oil to retain a hydrodynamic wedge at increased speeds as radial loads to the wheels increases. If the oil supply is already limited, it is reasonable that more failures could occur when running at higher than stock boost. Higher boost pressure also means higher exhaust gas back-pressure in the header, which means more axial force applied to the turbo thrust bearings, which is more potential for wear.

Immediate remedy

Replacement turbo. VF-40 and VF-46 turbos are available from Subaru dealers and the usual online genuine parts vendors. IHI does not supply genuine overhaul parts like replacement turbines, compressor wheels, bearing kits, seals etc. While there are CHRA kits out on eBay for around $250, there isn't too much info on how well that worked out. Even though you can buy parts it's not possible to DIY a turbo overhaul as the wheels needs to be balanced to extremely high specifications since the assembled compressor and turbine spin at such high rpms.
One practical repair is to purchase a complete center housing rotating assembly (CHRA) and fit your housings to that. Of course if your housings were badly damaged when the turbo failed this is not going to work for you. Six Star Speed does a rebuild service on the VF-40 for $500 using parts from Melett, which is a reputable supplier of pattern parts in Australia.

Several vendors now offer direct bolt-up replacements (upgrades) for turbos with the vertical compressor outlet unique to later LGT, OXT, WRX and FXT models. A list of suppliers appears in Appendix I below. While STi / early WRX-style turbos can be fitted directly to LGT models, this falls beyond the scope of this article.
Please note that replacing a turbo does not guarantee your problems are over. A second turbo failing shortly after the first is quite common.

Preventative measures before failure. Not every turbo fails but there are some points worth noting if you want to be the one to brag that you’re at 200,000 miles and still on the original turbo.

  1. Oil change interval and quality. Stick to the recommended OCI or have your oil analyzed if you think it might need changing more often. Use synthetic oil with the specifications that Subaru requires. There are many threads dealing with the question of which oil to use, all of which can be found via the search function. Definitely check your oil level regularly and keep it topped up.
  2. Banjo filter cleaning. You can remove, clean and replace the banjo filter every time you change your oil, or every two times or whatever makes you comfortable. Many people report having found debris on that filter even they thought their OCI was sufficient. Others have taken them out spotlessly clean. You could make sure it’s clean and sleep better at night.
  3. Banjo filter removal. There are two schools of thought about this issue, which can summarized as follows:
    • Pro-filter. Subaru put it there for a reason. Without the filter, dirty oil will contaminate the turbo bearings causing them to fail. If the filter is kept clean, there is no problem.
    • Anti-filter. If the filter is clogged, the turbo bearings will fail. It’s very hard to get to the filter and even Subaru techs often fail to find it. You might decide to follow Subaru’s lead and put more faith in the turbo being able to deal with contamination than your ability to keep up with the OCI or keep the engine topped up with clean oil. In this case you could pull the filter and toss it in the garbage.
  4. Oil line and / or filter upgrade. You may decide the stock oil supply isn’t enough or isn’t filtered well enough. Several kits are available that have bigger diameter lines. Some are filtered. More info in Appendix II below.
  5. Turbo replacement. Some people go so far as to replace their stock turbo with a different one in order to avoid all of these issues before they happen. Options in Appendix I below.

Preventative measures after failure. The turbo failing is very often not the end of the story. A great many people have suffered a second turbo failure shortly after the first and almost as many have reported an engine failure after the initial turbo dying. Chances are that if you have bearing particles in your oil you are going to have a bearing failure. You can try to prevent further problems with the following steps. Whether you take these steps or not you can still experience a second turbo or complete engine failure after the first, but it's cheaper and easier to try prevention than cure.

  1. Banjo inspection / cleaning / removal. If one turbo has failed it’s wise to look for the cause before installing another and just driving the car. You should at the minimum check the banjo filter is present and see if it’s dirty. A dirty filter is a sign that the turbo may have been running on a restricted supply of oil and failed from starvation. You may decide if you want to wash and replace it or ditch it or choose another oil supply solution altogether.
  2. Drain oil and check for contamination. A failed turbo bearing will probably leave contaminants in your oil. Left unchecked they will start to clog your oil filter and could pass either through or around it to cause more engine damage. Drain the oil and inspect it for bearing metal or steel leftovers from the turbine shaft.
  3. Pan inspection / cleaning. A really caring owner might want to drop the oil pan to see if there is any bearing material lurking in there, which didn’t drain out with the oil. Normally you’d expect if there is bearing metal in the oil, the pan is also contaminated. It's been reported that the shape of the oil pan is so complex and there are so many places for metal particles to get stuck, that it's really impossible to clean properly even with ultrasonic cleaning, and only replacement will guarantee no contamination re-enters the lubrication system.
  4. Engine flush. Whether the oil appears to be dirty or not, bearing debris can be present in the block and oil passages that didn’t drain out with the oil. A flush is a cheap way to help any such contamination to make it out of the engine.
  5. Oil cooler replacement. The oil cooler module which sits above the filter is reported to have such complex and narrow passages inside that contamination can easily build up inside and while impossible to clean properly, that contamination can escape slowly over time. You might have flushed the engine and cleaned the pan, but still have contaminants coming out of the oil cooler between oil changes. Only replacement will fix this, and it’s a $230 or so part here or here.
  6. Intercooler / intake manifold cleanup. If the compressor wheel has lost any vanes or parts of, take a look into the intercooler to see if they are loose in there. Nothing is likely to make it through the intercooler but better clean out any metal shards in there just in case. Anything that did make it through has either damaged something or not on it’s way into the exhaust. Either it did or it didn’t cause any damage.
  7. Debris in downpipe. If you have a catted exhaust there may be metal shards in front of the first one. Shake them out before reinstallation.
  8. Catted uppipe. Unrelated but well-documented issues with early cars having the cat in the uppipe come apart and destroy the turbine. While you have the turbo out for replacement, either gut the OEM pipe, fit a catless OEM pipe ('06~ WRX / '07~'09 LGT / any FXT or STi) or an aftermarket item. Note the stock cat is not ceramic and not as easy to hack out as the ones in the downpipes. Some owners have had a hard time removing it.
Appendices I and II appear below with info on repairs, rebuilds and replacement turbos and oil feed / filtration upgrades.

f1anatic 10-30-2011 06:48 AM

Excellent stuff. But I doubt it will help with the number of new "blown turbo" threads. It should be made a STICKY

fahr_side 10-30-2011 08:00 AM

Appendix I

Rebuild options. There are parts kits available from Ebay or what appear to be more reputable vendors like this one. There are now other vendors on eBay selling new CHRAs for about $250 but not much information is out there on how well those work in practice. Try searching the forum for recent experiences. Remember that a turbo failure puts your whole motor at risk from bearing metal shrapnel and then ask yourself if you can afford to cheap out on this. The chances are that if your VF-40/46 wore to the point that either wheel rubbed on it's housing, that part is scrap. Note also you cannot rebuild a turbo in your garage as the wheels absolutely need to be balanced with specialized equipment. You will not luck out on this one. An unbalanced turbo will quickly shake itself to death at high rpm and the shrapnel may destroy your engine, just like the original. Six Star Speed now offers a VF-40 rebuild service for $500. You could search and see what other members have to say about their experiences with this product.

Replacement turbo options. Note that upgrade turbos or those originally fitted to other models will need tuning to run safely. The larger turbos will need fuel system upgrades to reach their full potential.
This list is limited to direct bolt-up replacements which can be used directly with the stock TMIC or aftermarket equivalent. There are other stock-location turbos with different style outlets which need another intercooler solution to be used, but that is beyond the scope of this article. Vendors are listed in no particular order but OEM replacements come first. If you know of some unlisted turbos please post.

Section 1: Turbos which can sensibly be run on OE fuel system. While these do not NEED a fuel system upgrade they MIGHT benefit from one.

  • OEM replacement turbo from dealer or Subaru parts vendors. Plenty of used ones around but check condition carefully. Only the stock turbo can be run safely on the stock tune. It seems that the VF-46 can be used on an earlier car to replace a VF-40 without re-tuning on the condition that the original VF-40 pill is used. The VF-40 wastegate actuator does not bolt up to the VF-46 so you will either need to use the VF-46 item or modify your VF-40 actuator to fit. Note that some tuners require different sized pills for stage 2 tunes. Please note that only these turbos really qualify for use as a stage 1 or 2 build. All others are different enough that they fall into the stage 3 category.
  • Rebuilt VF-40 turbo from BNR Supercars. Bryan will have reconditioned units available for exchange at $650.
  • WRX OEM ('08) TD04 turbo from dealer or Subaru parts vendors. Also lots of take-offs around. This is a direct plug and play but needs to be re-tuned. The TD04 is a very solid little turbo which takes a lot of abuse. Although the turbine and compressor wheels are slightly larger than those in the stock IHI turbos, the housings are smaller and power potential is slightly lower. It does however spool instantly. You would want to start with the pills that came with the TD04. Note that '08 WRX models have one pill either side of the tee in the hoses. This works very well and you could just use that whole tube set-up.
  • WRX OEM ('09~) VF-52 turbo from dealer or Subaru parts vendors. Not quite so common used as they are in high demand. The CHRA in this one is much beefier than the VF-40/46 models but some WRX owners have had them fail in much the same way as seen on LGT models, and like the VF-40/46 they cannot easily be rebuilt. Please note that if you install this turbo on any other car than an '09~ WRX, Subaru will not warranty it if it fails. This turbo is roughly equivalent to an STi VF-48 or MHI TD05H-Evo16G and can do around 300whp on pump gas. Tune required.
  • BNR Supercars TD05H-Evo16G . MHI guts in VF-40-style housings. TD05H turbine mounted into a 7cm2 exhaust housing with the EvoX 16G compressors in a vertical-delivery compressor housing. BNR super-thread here. MHI has the advantage of replacement parts being readily available, and many vendors can rebuild them. The Evo16G model is so far perhaps the most popular non-stock replacement for a dead VF-40/46. $750
  • Kinugawa new bolt-up turbos based on MHI TD05H-EvoIII16G in either 7 or 8cm2 exhaust housing. Some more info in this thread. These turbos are made by Kamak, which is a major manufacturer of replacement turbos based in Taiwan, but are said to be of lower quality than the Kamak brand. Chinese parts are now creeping into these turbos.
  • ZAGE new bolt-up turbos based on MHI TD05H-Evo16G in a 7cm2 exhaust housing and with a 1bar actuator. These turbos are made by ZAGE which is a major manufacturer of replacement turbos based in Taiwan.
  • Kamak STS 16TX bolt-up turbos with new 9-blade turbine and billet compressor. I've tested these in both 7cm2 and 8cm2 housings and liked them. TD05H and TD06SL2-sized turbines available and compressors from 16GTX to 20GTX.
Section 2. Turbos which really want an upgraded fuel system to let them shine. Note that ANY turbo can be run on the stock fuel system but will have to be tuned to fall short of it's power potential.
  • Complete new TD05H-18G or 20G 8cm2 turbo from BNR Supercars, no need for a core, straight bolt-up replacement. MHI compressors from 18G to 20G available, along with billet wheel options or TD06SL2 turbines. BNR super-thread here. MHI has the advantage of replacement parts being readily available, and many vendors can rebuild them.
  • Blouch XT series bolt-up turbos based on MHI TD05 frames and billet wheels. Several options available. Well-known vendor but not immune to quality issues.
  • FP 68HTA bolt-up turbo based on MHI frame. FP brought this compressor to market themselves and it's very popular, especially with E85 users.
  • Kinugawa new bolt-up turbos based on MHI cartridges. TD05H-18G, TD05H-20G and TD06SL2-20G available. Some more info in this thread. This is a second-tier brand from Kamak, which is a major manufacturer of replacement turbos based in Taiwan.
  • ZAGE new bolt-up turbos based on MHI TD05H-18G, TD05H-20G, TD06SL2-20G or TD06H-20G in either 7 or 8cm2 exhaust housings and 1bar actuators. These turbos are made by ZAGE which is a major manufacturer of replacement turbos based in Taiwan.
  • Kamak STS bolt-up turbos with new 9-blade turbines and billet compressors. TD05H, TD06SL2 and TD06H-sized turbines available and compressors 18GTX and 20GTX.
  • AVO380 bolt-up turbo based on Garrett GT28R frame. These are hard to define as needing or not needing upgraded fuel as the results are all over the place.
  • AVO450 and 500 bolt-up turbos based on Garrett frames.
Please note that any replacement turbo is going to need a tune to run safely. Turbos larger than roughly a TD05-18G will probably destroy a stock 5-speed clutch in short order. How to upgrade the fuel system or transmission is outside the scope of this thread.

EDIT: I've compiled a list of supporting upgrades that turbo buyers should be aware of before choosing a snail, here. This will help you set realistic goals based on the budget you need to run a given turbo successfully.

fahr_side 10-30-2011 08:00 AM

Appendix II

Replacement / upgrade oil line solutions.
These will fit stock or usual MHI-based upgrade turbos. Individual turbo vendors may require you fit their oil line kit or specify one you must use if you want your warranty. If you know of parts unlisted, please post.

FP oil line. This can be ordered with an inline filter which is easier to get to than the stock banjo filter. Caution: Buy extra crush washers for this project if fitting the line to MHI turbos. I had to fit three washers under the banjo at the turbo end to avoid the fitting fouling the bearing housing. Some have needed four. A smaller number of owners report problems with the new banjo fouling the turbo inlet tube. The inline filter kit may need additional -4AN hardware to install it.

Infamous Performance oil line kit with inline filter, fireproofing etc. This is a very well thought-out kit but is new on the market. Will add more reviews and info in time.

Please be warned that after using the FP oil line for five years, my original hard steel AVCS line cracked between the oil supply banjo on the cylinder head and the (now capped) turbo oil supply union fitting. I believe this is due to the fact the hard line used to be supported / fixed higher up both by the banjo atop the turbo and also by a small bracket on the compressor cover. I fixed this by using an AVCS oil pipe from an n/a model which of course has no pipe branching off to feed a turbo.

Not quite an oil line kit, more like a filtration system revamp. Amsoil remote 2-micron filtration kits.

cryo 10-30-2011 08:33 AM

Vote for sticky as well. I typed up something like this on a different forum and it got lost in the clutter. Thanks for taking the time fahr side.


2.5GT_dude 10-30-2011 03:49 PM

what is a good replacement for the stocker if you plan on staying stage 1 or stage 2?

seabass07 10-30-2011 04:45 PM

How does the chra of the vf52 compare to that of the vf40 or MHI one used by bnr?

legacy360 10-30-2011 05:03 PM

Awesome compilation of information, thanks!

goneskiian 10-30-2011 07:30 PM


Originally Posted by 2.5GT_dude (Post 3614879)
what is a good replacement for the stocker if you plan on staying stage 1 or stage 2?

Another vf40. Stage 1 and 2, by definition, use a stock turbo.

Thanks fair_side! That writeup took some serious time to research and write. I hope others appreciate it as much as I do!


fahr_side 10-30-2011 09:29 PM

Thanks for all the positive feedback guys. More questions / info to add... just post and I'll get to it.

lowwill 10-31-2011 07:50 PM

No more turbo questions for me. Everything in one place. Good write up....

fiid 11-02-2011 04:56 PM

Excellent post. Nice work.

I don't think you should suggest the FP oil line upgrade though: My experience is that the Forced Performance line doesn't fit the Legacy GT without intake modifications and crush washer stacking on the turbo. Their inline filter cannot be used without additional AN-fittings either.

HAMMER DOWN 11-02-2011 05:32 PM

Another filtration option, ups your oil volume from 5qts. to 7qts. & filters your whole oil system down to 2 microns.

Amsoil 0w-30 SSO & Ea oil filters. ^^^ above^^^ My OCI avg.15k Running Cobb stage1 93 map, max boost is still 16.2psi up to 174k. Original motor & turbo are running like new with no shaft play.. Now I want stage 2+, GMS Crossover & UP pipe, & LW crank pulley & heat shield. Invidia DP & V2 cat back, Perrin TIH, Racer X FMIC. With running Cobb stage 2 93Oct. map. For the last 3000+ miles. Waiting upgrade stage 2, 93 Oct. AP map from Tuning Alliance.
I'm very happy with the reliability of this car at over 300k+, with AMSOIL lubricant protecting everything.

lieutenantcolumbo 11-02-2011 06:34 PM


Originally Posted by HAMMER DOWN (Post 3619279)
Another filtration option, ups your oil volume from 5qts. to 7qts. & filters your whole oil system down to 2 microns.

Amsoil 0w-30 SSO & Ea oil filters. ^^^ above^^^ My OCI avg.15k Running Cobb stage1 93 map, max boost is still 16.2psi up to 174k. Original motor & turbo are running like new with no shaft play.. Now I want stage 2+, GMS Crossover & UP pipe, & LW crank pulley & heat shield. Invidia DP & V2 cat back, Perrin TIH, Racer X FMIC. With running Cobb stage 2 93Oct. map. For the last 3000+ miles. Waiting upgrade stage 2, 93 Oct. AP map from Tuning Alliance.
I'm very happy with the reliability of this car at over177k, with AMSOIL lubricant protecting everything.

Crap I've only been putting in 4.2 quarts. :eek:
Should have known better than to trust the manual.

Jk I actually overfill anyway so I'm like 4.5 quarts. But that actually sounds like a more cost effective option than the KillerB pan if it really picks up two quarts. Might be worth looking into for that cost...............

fiid 11-02-2011 06:42 PM

Are there any less invasive options for getting a larger oil filter?

In other news - more feedback:
You mention gutting the up-pipe cat.... My reading (and experience) lead me to the conclusion that this is a serious operation. The up-pipe cat isn't a ceramic model and doesn't smash and drop out easily like other ones... I spent a couple of hours on mine before giving up and buying an aftermarket piece.

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