Subaru Outback Oil Consumption... Without a Trace

Messages
6
Location
West Virginia
Hello everyone! First off I wanted to share that I discovered this site earlier in the pursuit of trying to find an answer to a 8month old question regarding my motor oil. Which is, where is it going?! Also I'm not a mechanic by any means, but I do have technical knowledge and understanding of mechanics to a certain degree. Anyway, I hope I can present my situation clearly and get some more technical understanding from the more expert folks here. smile Basically my situation is this. I have a 2001 Subaru Outback wagon (2.5l 4cy engine) with 285,000 miles, that since last fall has been really eating the oil. To the tune of 2-3 quarts per every 3000 miles. I do not have oil flooding out on the garage floor here at home. Rather just a few drops here and there. Nor do I have blue or black smoke coming from the exhaust, or any smoke, at any time. The oil is just vanishing somewhere. I have hung out in Subaru forums and the common agreement seems to be possibly bad/failing/gummed up piston rings. Or to a lesser degree, valve seal issue. I haven't gotten a leakdown test as no mechanic / garage has the equipment or the time to do it on a vehicle of this many miles. In fact, one shop said they didn't want to do it because "what do you expect happens with a car with this many miles on it?". Taking time last fall I inspected under the hood and found a very oily/gummed up PCV valve and replaced it myself. The hose had oily residue inside of it. Leading me to believe pressure from the chambers might be forcing itself into the crankcase and that pressure pushing oil out to get burned off in the cat-converter. Of which the cat is giving me a check engine light P0420 error code. *IF* this is the case, short of pulling and replacing the rings which is going to be expensive, are there any steps I can take to see if I can restrict the oil consumption? Are their oil or fuel additives to help in the event the rings are gummed but not actually failing? FYI, back in 2010 I had work done to replace leaking headgaskets requiring the engine to be pulled. They showed me the inside of the piston chambers and they were pristine. At the time I had maybe 205,000 miles on the vehicle. The crosshatching was fully visible, not a single scratch in the chamber walls. If it helps, I've used Castrol GTX high mileage 10w30 or 10w40 oil over the years. I never had a leaking/consumption problem until about a year ago. There had been times where shops would use Valvoline or another brand (can't remember it) but never had any severe consumption issues. I've also used Techron fuel injector treatment, but after reading on here, that may not be the best to use...?? Anyway in my research Ive read that if the rings are just severely gummed up and not failing, this consumption can be reversed? True/False?? Also I did check my PCV valve again recently and to my surprise, it was just as coated in oil as the previous one was. Any advice or input would be great! I'm really hoping it's not the rings as I really don't want to pay to have that done or even consider a re manufactured engine. Especially when I'm putting available funds into getting a second vehicle (F150). Brad
 
Messages
25,823
Location
Upstate NY
Welcome. You have gotten your money's worth from the vehicle. Not sure this is severe. I would buy decent but inexpensive oil and keep it going. You could try Auto-Rx or Kreen. Compression test is needed. Here are the probable reasons: 1) All rings worn 2) Oil control ring gummed up 3) Bearings worn and spraying more oil on cylinder wall than the oil control ring can handle. Its a 2001, your in W Va where I assume they use salt so you have rust. Ride it out on cheap oil until its ready for boneyard.
 
Messages
211
Location
Sta Catarina, Br
First and second questions: 1) When you replenish the oil, what level do you put at? Note that you have 2 dots and one dent in the dipstick. 2)Do you check the oil level cold or 5 minutes after the engine is shut down and warmed up?
 
Messages
7,430
Location
beaver land EH?
If you can't find drips (leaks through seals, gaskets,etc.), then it's being "burned" at the catalytic convertor. There's no such thing called "disappearance" of oil inside an IC engine. If it manages to get into the combustion (chamber), it will be burned...small amounts of oil : cat convertor is more than capable of burning it to convert it to CO2 + H2O. Large amounts of oil being burned or your cat is becoming weak: that's the time when you begin to see/small blue smoke coming out of the tail pipe. Usually when your engine reach the latter stage, it would be very, very "significant" and cannot be ignored. Unless you have failed your local emissions testings(recertifications, etc.) otherwise: just drive it until it becomes a significant nuisance to others (mosquito fogger). Q.
 
Messages
2,367
Location
Virginia
Try some Rotella T6 or Mobil 1 Turbo diesel in 5W-40 for one change. Lots of detergents, may unstick some of the carbon around the piston rings.
 
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Messages
488
Location
Ohio
No doubt you are burning oil, likely worn, or gummed piston rings.. let's face it your engine has 285k miles at this point drive it til it dies, keep the oil topped off. My Saturn burns oil at the same rate as your Subaru roughly.. a little slower.. but you have TWICE as many miles on your engine. I would recommend sticking with high mileage oil, I recently switched from valvoline maxlife to Pennzoil high mileage, it seems to have slowed consumption slightly, I PHM is a little more stout than its compeitotrs.(supposedly it's a "full conventional" most high mileage oils on the market are semi-synthetic this includes your gtx hm, some will tell you synthetic slips past gummed/worn piston rings easier..)
 
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Messages
7,519
Location
North America
First off, welcome to BITOG...you will get comments and suggestions aplenty. Here's mine: It does sound like oil is getting past the rings, as evidenced by 2 gummed up PCV valves in rapid succession and the catalytic converter code. I agree with Donald that a compression test might be a good idea. However since that can be expensive and this is a sudden occurring problem I would try a good cleaner first and see if gummed up rings are the culprit. Worst off you will be is out an oil change or two. I've used Auto-RX and on an older vehicle it worked as advertised. Many people here swear by Kreen or MMO, the choice is up to you. A good cleaning oil during these treatments would be a great idea also, so some PYB or your choice of a solid detergent oil IMO is indicated. Since you've used 40 weights, the 5w40 Rotella is thumbsup Couple things: you said the shop did an oil change...well there have been several posts on here where the shop said they did the oil change but in fact did not; if that is the case with you and the oil was left in way too long then that could have caused the rings to be compromised. And this guy:
Originally Posted By: bawalker
.... In fact, one shop said they didn't want to do it because "what do you expect happens with a car with this many miles on it?".
Needs a slapdown. bop Please post back and let us know how it goes!!
 
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Messages
1,848
Location
Laramie, WY
I was clueless last summer and drove out of state to get an issue similar to yours fixed, since then I have been involved in 2 rebuilds and rebuilt 4 engines myself, I'm just a pharmacy college student, if I can do it while being almost clueless a year ago, you can do it. Rebuilt a 1ZZ-FE with 342k miles, since the rebuild it runs like a champ and doesn't burn any oil. Issue:completely carboned up oil control rings, the compression rings were in excellent condition because the car had good compression and power before the rebuilt.
 
Messages
2,253
Location
London, England
In my experiece Subarus use some oil. Less when driven round town. More on long high speed journeys. I would not be worried about 2/3 quarts over that many miles. VAG have said for years that a litre per 1000 miles is perfectly normal in one of their petrol engines. Have never used Auto Rx but i suspect it would be worth a go.
 
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Messages
35,701
Location
NY
You could try cleaning it, but it could just be the nature of the beast. A compression test would be a good idea too.
 
Messages
1,723
Location
Virginia
Welcome to the forum. It's interesting that the oil consumption seemed to come on so suddenly. As people have mentioned, I would try an oil known for cleaning and possibly might try a cleaning product like MMO. I personally am not a fan of fast working harsh cleaners that you only run for a few minutes, so check in the oil additive section of the forum for what products are viewed as safe and effective. You might want to also try changing what high mileage oil you use. Some people have used one without results, then switched to another and suddenly got the results they wanted. I'd suggest Valvoline MaxLife or Mobil 1 High Mileage, though people on here have started using Quaker State Defy, and Pennzoil High Mileage and have reported good results. Out of curiosity, what does your coolant look like. I realize that all that oil is not getting into your coolant, but figured it's worth making sure some of it isn't making its way in there.
 
Messages
1,019
Location
Va
Sadly 285k is at the point of diminishing returns. I might try Kreen at this point. If going cheap/easy to source is important than MMO or Rislone. Stuck rings are one possibility. Worn or a broken ring are also possible. Did they do the valve seals and cam seals when the HG was done? just curious. Can you change your own spark plugs? If so buy or borrow a compression gauge? These cars are not the easiest to change plugs on, but it's not impossible either. A 3" "wobble" extension makes it much easier. Small hands help too. Do you lack compression equally or just one cylinder? That would be good to know. Feed it oil, try 3-5k runs with rislone or MMO thrown in if you can get enough evidence to believe it's stuck rings. If it gets worse, consider Restore as a last hope effort if you need to wring another few months out of her. At the age and mileage, there are too many other things that wear out or go wrong. (Driveshafts, wheel bearings, brakes, diffs, tires, ball joints, Steering rack, etc..) At some point it just isn't worth putting anything else in a older car. I like subaru's quite a bit, but they are basically 200-250k cars.
 
Messages
1,848
Location
Laramie, WY
I was clueless last summer and drove out of state to get an issue similar to yours fixed, since then I have been involved in 2 rebuilds and rebuilt 4 engines myself, I'm just a pharmacy college student, if I can do it while being almost clueless a year ago, you can do it. Rebuilt a 1ZZ-FE with 342k miles, since the rebuild it runs like a champ and doesn't burn any oil. Issue:completely carboned up oil control rings, the compression rings were in excellent condition because the car had good compression and power before the rebuilt.
 
Messages
4,929
Location
Southeast
congratulations for keeping a car that long and that far. both of you have been troopers. GM was stating not long ago that 1 qt per 1000 miles (or something like that) was acceptable for their NEW vehicles. So if this was a chevy, you'd be meeting their corporate spec!! (sorry). all good advice above. I would suggest all as good: - compression check - may educate you more to the problem - rotella, MMO, Kreen, --- a regular dose of cleaners just in case it's stuck oil rings. - use the thick oils, like they've said. HM, rotella, etc. BUT, include a third-to-half quart of 5-20 synthetic. THAT combo did things I still do not understand when I was running a 240,000 jeep I6. - keep oil in the trunk, check it weekly, and don't worry until it becomes a true nuisance. With no repairs, you can keep going like this for a long time. - in the meantime, start saving the equivalent of a car payment monthly, Now. See if you can get 2 years doing this. You'll have a good down payment, reduced debt, and be ahead of the game. see if you can get the urabus to 315....! congrats--- great longevity!
 
Messages
22,188
Location
Colorado Springs
Originally Posted By: meep
all good advice above. I would suggest all as good: - compression check - may educate you more to the problem - rotella, MMO, Kreen, --- a regular dose of cleaners just in case it's stuck oil rings. - use the thick oils, like they've said. HM, rotella, etc. BUT, include a third-to-half quart of 5-20 synthetic. THAT combo did things I still do not understand when I was running a 240,000 jeep I6.
Sorry to hijack the OP thread, but could you briefly elaborate meep? Did the above fix any oil consumption problems you had in your Jeep?
 
Messages
3,018
Location
texas
bawalker, you sound well versed in engine mechanics. you have found the right spot to debate such topics. My advice would be to just keep driving it until it explodes and if your heart is still set on keeping the vehicle replace it with a junkyard engine. Your vintage has an EJ251 which is still very expensive, but a local junkyard might have one cheaper.
 

bawalker

Thread starter
Messages
6
Location
West Virginia
Thanks everyone for the great wealth of knowledge and input!! It's greatly appreciated! Now to see if I can sort out the info that was given and present a few more questions. smile I'm not answering anyone in particular, but responding to notes I took from everyone's replies. First off, I've never heard of Auto-RX or Kreen until seeing it here. Those are oil additives correct or are they involving full 'engine flushes'? I assume if they are additives that some sort of ration of 4:1 is used in combination with a thicker high mileage oil? As for MMO, is that the Marvel Mystery Oil I saw the other day at Walmart? I had seriously never heard of it before. Additive or full oil change replacement? Speaking of oil, I've seen Penzoil High Mileage, Rotella T6, Mobile1 Turbo Diesel (this can run in a gas engine??), Valvoline Max Life, etc. Also part synthetic vs non-synthetic. Is there a popular consensus on which is better at cleaning or slowing oil consumption? Do I just cycle through the thicker oil w/additives every 3000 miles as normal, or is there some systematic process to this? I know some have mentioned the longevity this car has given me already and riding out the problem as other problems could arise later on. I will say that this car has been garage kept, mostly highway miles driven in it's life. I'm not a speeding, off road, push it to the limits abuser. Rather it's the only vehicle I have right now and doubles as my personal and work vehicle. I've recently replaced the original driveshaft, on a second clutch, still on original transmission, and new OEM axles all over the span of the last 2 years. That's since the head gasket replacement in 2010. Oh, for transmission, I've been using a mixture of different oils as a 'cocktail' for 5spd manual transmissions that several Suby garages came up with and does work. So far no tranny issues! *fingers crossed* In fact regarding the catalytic converter, I had one replaced in 2008 with an aftermarket one (BIG time cheaper). Since then I've learned the first one may not have needed replacement vs just O2 sensors needing replacing or even the engine running a more rich fuel mixture. Possibly my own ignorance then cost me since I saw the P0420 code and the mechanic said time to replace it. Fellow Subaru forum members said OEM cat's are meant to last the life of the car... *IF* it's not burning constant excessive oil or fuel amounts. SO... that leads me to person who mentioned about being a pharmacy student and rebuilding. I would so love to rebuild my engine if needed! I work in computers/electronics so I'm mechanically minded and think it would be a great challenge and learning experience. However at the moment I have just 1 vehicle, thus no secondary vehicle; I rent, thus no place to take time to work on it; and lastly no tools to use to do an engine pull. Short of replacing the cat/exhaust system (got some rusted rattling going on), nothing else is really needed with the body, struts (replaced 2 years ago), drive system, etc. That's why I'd hate to see it goto the bone yard, esp when I think I could get 400k out of it. Maybe? Because I run my own business I try to keep a tight financial ship, have no major debts (maybe $5k total debt to my name) and enough right now to pay 50% down cash on a 2 or 3 year old supercrew F150 with some left over. My intentions have been to get a second vehicle here soon that is newer and can offload any transportation if the Subaru has worse problems. OH, I forgot to mention (from the first post) that I did have valve cover gaskets replaced in January. As part of my diagnosing the disappearing oil and my car backfiring some, I checked the plugs. Passenger side plugs were oil coated and one in the driver side cracked. The backfiring happened one afternoon before I parked it. Replaced with NGK iridium plugs and had the seal replaced thinking that was what was causing my oil loss. Sadly that reduced my oil consumption by 1/2qt every oil change. Sorry for the rambling, just putting out all the info I can think of in hopes of the best advice possible! Thanks again!!
 

bawalker

Thread starter
Messages
6
Location
West Virginia
And I forgot to mention, there is no puff of white smoke when starting up. Or any smoke at any time. Leading me to think that the valves might be ok.
 
Messages
1,723
Location
Virginia
Originally Posted By: bawalker
Thanks everyone for the great wealth of knowledge and input!! It's greatly appreciated! Now to see if I can sort out the info that was given and present a few more questions. smile I'm not answering anyone in particular, but responding to notes I took from everyone's replies. First off, I've never heard of Auto-RX or Kreen until seeing it here. Those are oil additives correct or are they involving full 'engine flushes'? I assume if they are additives that some sort of ration of 4:1 is used in combination with a thicker high mileage oil? As for MMO, is that the Marvel Mystery Oil I saw the other day at Walmart? I had seriously never heard of it before. Additive or full oil change replacement? Speaking of oil, I've seen Penzoil High Mileage, Rotella T6, Mobile1 Turbo Diesel (this can run in a gas engine??), Valvoline Max Life, etc. Also part synthetic vs non-synthetic. Is there a popular consensus on which is better at cleaning or slowing oil consumption? Do I just cycle through the thicker oil w/additives every 3000 miles as normal, or is there some systematic process to this?
Kreen, MMO (Marvel Mystery Oil), and ARX (Auto-RX) are more additive then flushes. I'm not nearly as familiar with Kreen, but people seem to like it. With all three, you add it to your oil and run it for a while (how long depends on the product). A flush is more of a product you add, run it for several minutes, then drain it out. As for the oils, Pennzoil tends to make really good oils, they're owned by SOPUS (Shell), and really all of Shell's products are good (Shell oil, Quaker State, Pennzoil, Rotella). M1 HM, Pennzoil HM and Quaker State Defy seem to be getting more attention on here, previously Valvoline MaxLife (available as a full synthetic, and a semi-synthetic) were the HM oil darlings on here. However, any of those should be a good HM oil, and are worth trying to see if they can result any improvement over the HM oil your'e currently using (not a diss on Castrol, just you've seen what their HM oil can do, might as well try something else for a bit to see). As for the other oils, Rotella T6 and M1 Turbo Diesel, yes you can use them in non-diesel vehicles. They protect great, they're very stout oils, and they have excellent cleaners/detergents. Good luck, I hope you get it all worked out, Subarus are excellent vehicles and I'd like to hear you got a couple hundred thousand more miles out of yours.
 
Messages
1,327
Location
Washington for now
Originally Posted By: bigjl
In my experiece Subarus use some oil. Less when driven round town. More on long high speed journeys. I would not be worried about 2/3 quarts over that many miles. VAG have said for years that a litre per 1000 miles is perfectly normal in one of their petrol engines. Have never used Auto Rx but i suspect it would be worth a go.
Yep my 99 is like that. its got 235k on it now. i drove it on a 800 mile trip and it sucked a quart of oil. i can drive it 3k miles local it it will suck a quart. the interesting thing is that it still get 23mpg mixed and 28 all freeway. oil is cheap. if it runs well i would just keep adding oil till it dies
 
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