By on August 18, 2010

TTAC Commentator Detroit-Iron writes:

I have an ’09 Subaru Legacy with 26.5k on the clock.  I drive close to 600 miles a week, all on main road or highways at a steady 75 mph with few exceptions.  It is pretty warm where I live now, but it is not dusty here in the mid Atlantic, way too much humidity, and my direction of travel means I rarely run into traffic.  Recently I got a CEL, I took it to Advance auto but the guy couldn’t find the port.  The next morning the CEL was gone, but after work it had come back.  I tried filling the gas and re-tightening the gas cap to no avail. Ominously it also developed a rattle at 3k rpm.   After I got home (120 mile trip with no cruise control) I went back out to the store that evening and the CEL was gone.  The next day I took it to a dealer who didn’t have time to diagnose but said he would take if for a quick spin.

When I told the mechanic about the rattle he looked at me like I had just said that I enjoy biting the heads off of puppies because he “never drove a car over 3k rpm.”  Of course, the car turn 3k at 72 mph, so I don’t know where he drives.  Anyway, he said that the rattle was just a loose heat shield (he did not look under the car to confirm, because he had been a Subaru mechanic for 17 years and didn’t need to).  When I was driving over to the dealer I notice after going around a sharp cloverleaf that the CEL (which had not been on) lit up.  The next day I babied the car to work and the CEL did not light.  On my way to dinner that evening I confirmed that a sharp turn would cause the CEL to light up.  I finally got to a different dealer to diagnose for reals the following day.  After looking at it briefly he said that there wasn’t any oil in it, or at least not enough to even touch the dipstick.  They changed the oil, ran it for a while, and changed it again.  The CEL has not returned but the rattle never left.

I always run synthetic oil, partly because I am pretty lax about getting it changed.  Usually I buy Mobile 1 from Wal-Mart and get it changed at Jiffy Lube.  The last time I was at Jiffy Lube I just told them to use their synthetic.  When this started there had been 9600 miles since the last oil change.   The vehicle is not leaking any oil at all, and the oil pressure light never came on.  Although I knew I needed a change (and if fact was planning on getting it done the day the CEL came on), considering that I drive almost exclusively on the highway, I didn’t think 9600 was entirely unreasonable.  The dealer said that synthetic or not, it should be changed every 3750.

What say you?  Did I ruin it?  Should I toss it in the garbage and get a new one?  Any idea why the oil pressure light never lit up?  Do you think Jiffy screwed me and just used conventional?

Sajeev Answers:

Hey man, thanks for writing again. Love my “frequent flyers.” Unfortunately that dude at the dealership is right; Subaru recommends oil changes (turbocharged models only) every 3750 miles.  Which sounds all kinds of wrong to me.

Maybe Subaru is recouping their crippling warranty claims via oil changes, instead of making their owners pay for thrashing their complex boxer-turbo-manual-AWD products?  That would explain the NASIOC’s sub-forum created to handle warranty denials. Not that I cruise every car forum on the planet, but this looks like a Subaru-only kind of concern. Well maybe Nissan GT-R folks feel your pain, too.

But I don’t see anything wrong with your actions.  I just don’t see your oil changes causing engine rattles, but maybe a CEL will make me change my tune. I’m gonna ask you for the code(s) that caused a check engine light.  This makes whatever I write far more accurate and relevant.

Detroit-Iron writes:

Okay, I got the codes: P0026 and P0028, both are about the intake valve solenoid.  I think they correspond to the RH and LH cylinder banks.  I also determined that the rattle has less to do with RPM than throttle position.  Anything over 2k, if I just lightly step on the pedal <10% it rattles pretty badly.  Closed throttle or more than 10% and it goes away.  It might be coming from the driver’s side but I can’t really tell.  The CEL has not come back, so that is good, and I found some horror stories of $1000+ repairs to replace the solenoid, so $220 for a glorified oil change isn’t too bad either, but I am worried about the rattle.  It doesn’t seem to be down on power though.

Thanks for making me get the code.  I was pissed off about the whole situation and didn’t really want to talk to the mechanics again, but that is obviously not a productive way to think.

Sajeev Answers:

As predicted, with those codes, my tune won’t change: you didn’t ruin the car. If only the rest of our lives could be solved so easily.  Imagine sticking an OBD-II code reader into your significant other’s…umm…”test port” when they act bizarre.  And if only your co-workers came with Check Engine Lights!

And with those codes I used the “search” feature on NASIOC to find this thread.  Not being a boxer expert by any means, I feel this is your problem. The solenoid(s) could be loose or the timing chain/tensioner could be at fault.

So post your question and hypothetical solution on a Subaru forum like NASIOC.  Once you get savvy, wholly independent minds on the problem, take it to a mechanic as an informed consumer. I suspect it’s time to drop a subframe and tear that motor apart.

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36 Comments on “Piston Slap: Feelin’ Love For Forums, Check Engine Lights...”

  • avatar
    Educator(of teachers)Dan

    Needless to say, never go back to dealer #1 again. “I’ve got time to drive it but not time to check the CEL?” Seriously? You don’t have time to plug a reader into a port and get the damn codes? And the mechanic who doesn’t have to look, he just “knows.” Good grief.

    • 0 avatar

      My elderly dad got hosed a few months ago for $500.00 worth of scheduled maint at a Milwaukee area Suby dealer. There was 12k or so on his leased Forester and it did not involve brakes or any other complaint.

  • avatar

    A pretty important question is whether or not this is a Legacy Turbo or not. 9600 miles between oil changes on a turbo EJ25 is just begging for a spun bearing. The Subaru flat engines have a propensity to consume oil, especially the turbo models.

    There is also a rumored correlation between using Mobil 1 and spun bearings on EJ20/EJ25 turbo engines. The thought is that Mobil 1 tends to be “thin” for it’s rating. My EJ20 seemed to guzzle Mobil 1 (to the tune of 2-2.5 quarts in 3k), switching back to dino oil reduced this consumption to less than a quart in 3k.

    In addition, the dipsticks on these cars are all but useless if you’re checking the oil hot. They need to “settle” down before you will see any oil on it, and it still may not be accurate.

  • avatar

    I would probably have done the oil changes as required by the manufacturer, at least for the factory warranty period. I sincerely hope that you didn’t tell the dealer that you didn’t change your oil in 9,600(!) miles, because if you did, you just gave them a way out of paying any and all warranty claims on your car that could possibly be attributed to engine oil or driver neglect.

  • avatar

    Is this a turbo Subaru? Disappearing synthetic oil (particularly Mobil 1) has been discussed on all the major Subaru forums, so I’ll stick with my own experience and that of a friend with the same year/model of Subaru.

    When I traded my beloved RS for a WRX in 2004 (05 model year), I decided to use synthetic oil after about 10,000 miles. Mobil 1 vanished from the pan at an alarming rate. I never got a CEL but I did get a scare after a 15 hour drive when I pulled over for gas and found the dipstick didn’t have any oil on it, nor was there any the next morning after I’d gotten home. I drained and re-filled the oil and checked it at every fill up and watched it drop. At about 20,000 miles I switched back to regular oil and have had no noticeable disappearances (now at 96,000 miles).

    I know at least one other person personally (that is to say, as a person) with an 05 and the same experience, and as I said there are others on Subaru bulletin boards with the same experience. Suspicions range from loose ring design to tiny oil molecules as none of these engines are leaving pools on the ground. A simple solution may be to just use regular oil; mine’s changed every 4-6000 miles and has no problems to date. But remember this is regarding a 2005 model with totally different components (being a 2.0L motor versus any motor in a 2009 Legacy), so it’s hardly a guarantee you’re having the same problem.

    I’m not sure if the CEL relates to the oil or not. Maybe the solenoid is affected by heat and the lack of oil caused it to go up. But that’s only a very wild guess. Is the ODBII port no longer to the left under the steering wheel?

    The rattle is something that would need to be diagnosed on the spot, but the description would probably lead most people to suspect a heat shield or some other bit contacting the exhaust when you’re loading/unloading the motor’s torque.

    Best of luck with the car.

  • avatar

    One other thing to consider–which is a “differential diagnosis” for heat shielding–is the catalytic converter(s).

    I had one go bad recently, and the diagnosis guesses ranged from the clutch throw-out bearing to the heat shielding to the engine mounts. Sometimes the cat will drop chunks that rattle at certain RPM and drive you crazy. A few taps on the cat with a rubber mallet should confirm. If your car has two parallel cats (which most dual-bank engines do), you can do a direct comparison of the two to figure out the culprit.

    If that’s the case, then you’re covered under both the mfr warranty and the federal emissions warranty, FWIW. Maybe a longshot, but just throwing that out there.

  • avatar

    Sajeev, the EJ25 in his 2009 Legacy doesn’t have a timing chain, it has a belt. The H6s and the revised version of the EJ25 slated for 2011 year will have a chain however.

    Subaru’s are notoriously rattly cars, all of them are in fact. Whether it be interior or mechanical components, everything in these cars rattle. Get used to it.

    Info on the 20011 EJ25 changes:

  • avatar

    Subaru requires turbos to have changes every 3750 miles, and will require turbo engines to run on synthetic in 2011.
    The Subaru Service manager I spoke to said Subaru turbos use/burn up more oil when Synthetic is in the crankcase. Whether Subaru will tighten the seals up in 2011 is unknown.

    What color was that 9600 mile oil? If black, the oil was full of contamination and ready for recycling.

    My ’09 XT so far does not burn oil (high grade regular) but using a former Exxon’s chemist’s additive helps (called Auto Camguard, it’s an oil additive with real science and testing behind it – and no, I don’t work for them. :-) ).

    • 0 avatar

      I’d read the rumors about 3750 mile oil changes on turbo Subarus, but if they change the service interval you are supposed to get a notification letter and I never did for my ’05 LGT. There probably isn’t any harm in more frequent changes except for the expense, but if you let these engines sludge, the very fine screens in the turbo oil lines can be blocked, and that’s a sure way to kill the turbo.

      Mobil 1 (10W-30) doesn’t disappear from my crankcase any faster than the dino oil did – I’m about a pint down at change intervals of 5000 miles.

    • 0 avatar

      jet_silver, they didn’t change the service intervals for previous model years, they only made the “recommendation” that the 3750 oil change be followed. Apparently there is some legal issues with changing service intervals after the car has been sold, so Subaru could not just change it. It would pay to heed the advice though.

      Sajeev et al: Subaru changed to the 3750 oil change because there are oil feed lines using Banjo bolts with little filter screens in them (to keep junk from circulating? notably the turbo oil feed line has one) on these motors. Apparently some of the turbo motors were failing and the clogged screens were the culprit. Subaru’s solution was to reduce the change interval to reduce the possibility of gunk buidling up on the screens starving oil to key parts of the motor. Kinda bunk if you ask me, but it is what it is, worth following. This stuff was documented in discussions on involving a Subaru tech who seemed to know his stuff.

      As for the valve solenoids, sounds like an internal motor problem with the AVCS? Could have been oil starvation from running low, and cornering sloshed the oil away from the pickup. The AVCS system uses oil pressure to work I beleive.

      Also the Subaru 2.5s are known for occasionally in rare cases having defectively brazed oil pickup tubes. Another problem Subaru hasn’t addressed over the years other than replacing motors under warranty.

  • avatar

    It might be oil sludge, formed when you ran your engine low on oil and the small amount of oil that moved through your valvetrain overheated. If your intake valve solenoid draws too much current because of reduced lubrication, it might trip a CEL. The fact that an oil change made the CEL go away might indicate that the solenoid is sufficiently lubed now.

    Sludgy valvetrains are noisy at lower RPM, but at elevated RPM they quiet down. The “rattle” you’re hearing might not be a resonance due to a certain RPM as would be the case with a heat shield, it could be in the valvetrain.

    Buy a bottle of SeaFoam motor treatment and try to clean out any sludge that may have formed. You’ll have to change the oil a few times over the next 1000 miles, but if I’m wrong you’ll only be out $9 + oil change costs instead of a few G’s for motor repair.

  • avatar

    Whoa, that much oil consumption with synthetic? We’ve been turbocharging vehicles (OEM and aftermarket) for decades without this problem. Does Subaru live in the same world as the Model T?

    I’m gonna have a hard time recommending Subies to most anyone in the New or Used series…and this thread will be my constant link-back for proof.

  • avatar

    Thanks everyone.

    2 Things

    It is not a turbo, just the regular 2.5 l 4 cyl. I thought I had put this in the original email but I guess I forgot to.

    Unfortunately the sticker from Jiffy lube was in the window. I should have said that I changed it myself since then but I am not that swift. FWIW Between the time I sent this in to now it is up over 31k, so the warranty is expiring soon anyway.

    • 0 avatar

      While I’m halfway kidding, you should go get your Ranger back. At least the Vulcan motor won’t do this.

    • 0 avatar

      My 2003 Forester XS is in the shop right now having a periodic phantom CEL and rattle checked out. I removed one heat shield a year or so ago, and I think the shop removed the other the last time it was in, so now I wonder if it isn’t the forward (as the noise seems to be from up front) cat as noted up-page. I don’t think I’m under warranty any longer, however.

  • avatar

    Of the 15 cars I’ve owned during the past 13 years I’ve never seen a car light up the CEL as my Outback. It came on so often I thought it was the turn signal indicator. Other friends with Subarus here in Colorado have similar experiences. What is it with Subarus and CELs? I suspect the CEL has a timer circuit telling it to go off at random intervals.


  • avatar

    About the CEL – even if it is not lit up at the moment, a data reader ought to be able to pull up all codes activated over the past 30 days. So any dealership should be able to plug in and get the code at any time. You shouldn’t have to wait until the CEL is on for them to diagnose.

    Also, a generic reader isn’t that expensive. Mine has paid for itself several times over already.

  • avatar

    As the problems mounted – or went unaddressed – on my former 02 Passat, I finally decided to trade it at 33k miles rather than start paying for post-warranty repairs on a car that wasn’t becoming more reliable with time.

    Maybe you should consider doing the same. Dealing with this nonsense after the warranty expires will be very unfun. And I wouldn’t get an extended warranty, either, since that does nothing for the car’s reliability.

  • avatar

    You seriously used Jiffy lube to change your oil? Thats asking for trouble in my opinion. Waiting as long as you did on oil changes is asking for a sludged motor. BMW recommends 15,000 miles between changes. Totally insane. I change at 5000 miles or 1 year. If you ever have seen pictures of the inside of the motors that follow BMW’s schedule you would cry. Oil is cheap motors are not. This is just my opinion, but Mobil one is the Shemp of motor oils.

    • 0 avatar

      Who are the Curly and Moe of motor oils?

    • 0 avatar

      Let me add to that – you used JiffyGlub to change your oil and then you happily put close to 10K miles on an unknown bulk oil?

      C’mon now, even if the problem is unrelated you should know better than that.

    • 0 avatar

      I won’t comment on Mobil 1 extended oil-change intervals, but I wouldn’t let ‘iffy-lube change my radio station, let alone my oil.

      I’m not saying they mess it up every time, but if you’re going to stay with them, a 3-month / 3K interval will limit the damage. And go with the cheapest oil that meets spec.

    • 0 avatar

      Regardless of where you have your oil changed, ALWAYS check the oil level immediately afterward. Many times those places never check a spec sheet and just put in whatever amount of oil the grease monkey thinks should go in.

  • avatar

    I have a 2006 Legacy GT (turbo) and used the same 5w-30 Mobile 1 that i had left over from my RSX Type-S. I noticed quicker than normal oil consumption in everyday driving and ~1 quart of loss during track days.

    I switched to German Cartol Syntec 0w-30 and my oil consumption issues have completely disapeared, even at track days!

    I had noticed with my RSX-S that the car would be down 1/4 quart of Mobil 1 after a track day.

    German Castrol is pretty rare here, so when i find some (even better if it is on sale) I stock up. I have about 20 litres in my garage right now.

  • avatar

    Do the Subarus of this era have the same knock sensor issues as the early 2000’s? If the knock sensor was intermittently failing that might cause the CEL

  • avatar

    The key points in the story above are:
    “9600 miles since the last oil change”
    – Wow, really?

    “he said that there wasn’t any oil in it, or at least not enough to even touch the dipstick.”
    – A 9600 mile run since the last oil change without checking it, this is probably true.

    “The vehicle is not leaking any oil at all”
    – Come on… All engines consume some amount of oil. Simply put, it is burned and shot out the back.

    “and the oil pressure light never came on.”
    – If you ever see the low oil pressure light come on, its usually too late anyways.

    On a side note, please be aware the difference between a low oil pressure light and a low oil level light, as I’m pretty sure Subaru’s don’t have a low oil level indicator. In other words, check your oil level often, don’t wait for a light to come on in your dash.

    I have a 07 STi, currently at 50k miles. Mobile 1 5w-30. I change it every 3000 miles. Is changing it that often necessary? No. But I do it anyways.

    During those 3000 miles, no noticeable amount of oil is lost. I also keep receipts of my oil and filter purchases in-case of warranty issues.

    • 0 avatar

      All I can say in my defense is that I had similar lapses using Mobil 1 with a 2003 Focus and a 2000 Ranger with no ill effects(and they’re not even Japanese!), and that this is the basest of base Legacys, not a superfresh STi. If I had an STi, I would reasonably expect 10qt oil changes and a decent oil burn rate. What I have is really a toyhonda appliance with the very slightly fresh addition of AWD. As the owner of a glorified appliance I expect to be able to neglect the sh1t out of it and complain bitterly when there is a problem.

    • 0 avatar

      Apparently Mr. Iron condones neglecting his car, so all the advice in the world for properly maintaining it isn’t going to do much good.

  • avatar

    I had a very simmilar experience to yours, however it didn’t involve oil at all. I own a 2007 Mazda CX-7 MT, which at the time of the incident had clocked about 45-50k kilometers. On a trip to Austria, it started rattling. At first I was panicked, as I was sure the flywheel was to blame; I would accelerate, and it would make a terrible rattle. Moreover, it seemed to make more of a rattle when I steered, which was extremely strange. I decided to just drive the car until it failed, promising to myself to buy a BMW X6 (hush hush) when I get back home. However it lasted the return trip to Romania, and as soon as I got there I took it to my Mazda dealer, expecting a hefty bill at the end of the day. Surprise surprise, it turned out that the belt driving, among others, the power steering was dirty; they cleaned it for 40 $. Never had a problem since. I know this may not be your case, but it wouldn’t hurt to check it out, as I basically experienced the same problem: rattle when accelerating, accentuated when steering. However, in my case, there was no check engine light involved.
    Best of luck

    Edit: Since you were apparently out of oil, shouldn’t the oil light have come on? When I was low on oil in my 3.0 TDI Audi, it just said ‘Add max. 1L oil’, no check engine light!

  • avatar

    “and the oil pressure light never came on.”
    – If you ever see the low oil pressure light come on, its usually too late anyways.

    I don’t know how there could be low enough oil pressure to trigger a CEL and not light up the Oil Pressure indicator.

    BTW, the term “idiot light” may not be sufficient. A short while ago a friend of my son gave me a lift to the bank. On the way home I noticed his oil pressure light was on and despite everything I told him about having to stop and get oil immediately, he kept saying “I guess I have to take it to my guy.” Even after I showed him the dry as a bone dipstick when he dropped me off at home, he still wouldn’t go buy oil. He’s not stupid, actually he’s pretty book smart, but some folks are convinced that they can’t do anything on their cars.

  • avatar

    We’ve had 3 Subies over the past 20 years (still have 2 of them)…the only 2 things I can recommend are to change your oil more often and find a really good non-dealership mechanic to work on it.

    We are lucky and have a garage nearby that only works on Subaru’s. he’s not a whole lot cheaper then the dealership, but I trust every word that comes out of his mouth.

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