Checked oil and was down 2.5 Qts!

[mclement]

I've got an '03 outback 4 cylinder with almost 100k and was getting ready for another oil change, probably 5000 miles since last. I'm on my way home from work and the oil pressure warning light flashes for a split second around a corner. Immediately check oil when I get home(a minute later) and see nothing on the dipstick. Walk to the gas station and it takes 2.5 quarts to get it to Full on the dipstick.....The manual says the capacity is 4.2 quarts so my question is..."did i ruin my engine for letting it get so low on oil?" I haven't been driving it long or hard recently...also haven't noticed any leaking, burning, or unusual noise....Any input would be greatly appreciated.

[Platinum_Racing]

The answer to your question is no. The oil pickup is on the very bottom of the oil pan. The pump takes oil from the bottom of the pan to ensure it always has oil, despite oil level. The light came on because the g-force of the turn forced all the oil to one side of the pan, preventing the pump from sucking in any oil. It takes much, much, much longer than a few seconds without oil pressure to damage an engine. All components that require oil are lathered in the stuff, so despite the lack of pressure there was still enough oil on the parts to keep them more than happy.

 

You might want to pop the hood and see if there's oil on the timing belt cover, the bottom of the heads, or around the oil pan gasket, as any leaks in these places would mean something to replace. If it's all clean then fill up the system and wait a week and check it again. If it's low and there is no oil on the exterior of the block then the engine may be consuming the oil internally (IE burning the oil) meaning the piston rings are worn (Which is unlikely at 100K on any EJ engine equipped Subaru).

[mclement]

Thanks for the reply...I took it and got an oil change, they said it is normal for a car to require oil when you go 5000 between changes and when the weather fluctuates a lot. They didn't see any leaks and said it was going to be fine. Still don't really know what to make of it. Do these cars consume oil like that?

[Platinum_Racing]

No car should consume that much oil, but all cars do consume some, even new cars. Older cars consume more oil due to worn piston rigns and worn valve guides. The reason is because there are tolerances between the piston rings and the cylinders. Manufacturing processes aren't perfect, so there will always be some space between the rings and the cylinders. Plus, the oil rings around the piston designed to maintain cylinder wall lubrication aren't perfect either. There needs to be a thin layer of oil coating the entire cylinder at all times to minimize scratching. As a result some oil is burned away when ignition occurs and the piston is pushed down. The oil exposed to ignition can be partially consumed during this time. Another place oil gets consumed is through the positive crankcase ventilation. Positive crankcase ventilation (PCV for short) is required because blowby (Compressed air and gas that flow past the piston rings during the compression stroke on all internal combustion engines) needs somewhere to go, or else pressure will build in the crankcase potentially damaging gaskets, bearing seals, or in very rare extreme cases even the block itself. Federal law requires this pressurization in modern vehicles to be vented back into the intake of the engine (To reduce emmissions and oil slicks all over roads, parking lots, and driveways which used to be common place up until the 1930's). As this gas travels through the crankcase, it picks up oil and carries it back into the intake through the numerous vacuum (Breather) lines generally coming off the valve cover somewhere. This gas carries the oil back into the intake, where it all gets consumed by combustion. The final place oil can seep into the engine is through the valve guides. Valve guides hold the valve stem in the cylinder head. Due to manufacturing tolerances and wear over time, these guides can allow oil that lubricates the valve system in the head to enter the intake (Or exhaust) ports. Usually oil is too thick to enter these tolerances by itself, but as air moves through the intake ports past the valve guides, a low pressure system is created in the port sucking oil through the imperfections in the valve guides. This only really happens in older engines where scratches have formed on the valves and valve guides (Or in engiens with valve guides that have become too big from wear). If oil were to enter the exhaust port, it would be burned quickly. If enough oil gets past the valve guide on the exhaust valves the engine can produce smoke from the exhaust pipe. This is usually accompanied by one or more noisy valves from the valve knocking slighty in the valve guide (Not to be confused with noisy lifters/rockers). Smoke could also come from the combustion of oil through the rings, intake valve guide, or PCV system, but an abundance of smoke could mean exhaust valve guides in particular.

 

So, in conclusion, the length of time you went between oil changes probably contributed to the oil consumption. Altitude/weather could contribute, but I've never heard of a 2.5 qt drop from altitude/weather alone. These combined plus the fact that the engine is probably drinking small amounts of oil through all the above listed places could add up to 2.5 qts over time.

[ouch1011]

2.5qts in 5000mi on a 100k car is really not bad at all. Typically dealerships won't even look at your car for an oil consumption concern unless its more than 1qt per 1000mi.

 

For future reference, you should check your oil every so often.

[987687]

Unless you are running synthetic you should really change your oil more often. I try not to go more than 3,500mi on my car, I think I did 4000mi once. But at nearly 100k (I think I have 99,800mi now....) my engine doesn't burn any oil between changes at all. I have never had to add a drop. As Platinum_Racing said, engines are all made to be within a certain tolerance, some are right at the edges, some are right in the middle. It is luck of the draw.

[gathermewool]

Unless you are running synthetic you should really change your oil more often. I try not to go more than 3,500mi on my car, I think I did 4000mi once. But at nearly 100k (I think I have 99,800mi now....) my engine doesn't burn any oil between changes at all. I have never had to add a drop. As Platinum_Racing said, engines are all made to be within a certain tolerance, some are right at the edges, some are right in the middle. It is luck of the draw.

 

 

I disagree that 3500mi is the limit for a good SM-rated oil, especially when oil is being added periodically due to consumption or leakage. 5kmi is a good number for any decent oil, and can probably go much, much longer. IMHO, you gave yourself more than half an oil change when you added 2.5 qts, anyway

[987687]

Good point on the consumption thing... My car doesn't eat oil, and I'm trying to keep it that way. The service records showed oil changed every 3k to 4k miles, so it must have done some good if the engine is in such good shape at 100k.

[gathermewool]

Good point on the consumption thing... My car doesn't eat oil, and I'm trying to keep it that way. The service records showed oil changed every 3k to 4k miles, so it must have done some good if the engine is in such good shape at 100k.

 

How do you drive your car? I normally (90% of the time) drive very easy, and that equates to zero consumption on a 97 LGT with 197kmi. If I drive a little more aggressively (i.e. in a hurry from light to light or monster-stomping the pedal on the highway ) I can drop down a qt in 1kmi. I've found this to be very predictable, at least for my car.

[987687]

I ALWAYS let my car warm up for a minute or 2, then drive easy till it is completely warm. Then for the most part I drive easy, under 3k rpms. But I did have a big road trip with over 2000lbs of stuff in my car and tied to the roof. So I was running it a bit hard for almost 500 miles. Then on the highway... I drive FAST, I accelerate hard on back roads, squeal tires around turns... I'd say 70% easy driving overall, and 30% having fun

[gathermewool]

Very nice

 

OP: If you're not leaking oil, then you're definitely burning it. I, too think that it's too early for worn rings if you've been changing the oil since new ever 5kmi UNLESS you've had this consumption issue for a while and have been running a couple of quarts low before each oil change. While a car that doesn't lose oil can run 5kmi + easily on 4.2 quarts of regular dino-oil - longer if you keep up with consumption by adding some now and again- I think gradually lowering to 2.5 qts low near the end of an OCI is REALLY taxing the oil to the point that it's probably rapidly breaking down.

 

Do you usually check your oil level often or just run from oil change to oil change? If the aforementioned is applicable you may have carbon build up in your ring pack which would cause increased consumptions and/or lowering compression over time. If this is the case then I'd recommend using a good synthetic with known cleaning ability over the next few OCI to clean things up a bit. I've also heard good things about Auto-Rx. I used Auto-Rx myself this past spring, but didn't notice much change since the guy who owned the car before me had the engine apart and soaked the pistons in Marve Mystery Oil while he had the heads off during a head gasket replacement, and he and I both used good oils at reasonable OCI. I admit I used to change the oil every 3kmi before I started to look into extended drains.

[Platinum_Racing]

I always change my oil when I should. Sure, adding 2.5 quarts is like half an oil change, but you're still using the same filter. By that logic you could just keep adding oil instead of replacing it and go forever without an oil change, but you're still using a contaminated, old filter.

 

Change the oil like it says in the manual. Synthetic oil does have the potential to last longer, but don't trust what it says on the bottle of synthetic oil. Of course they're gonna say its proven to last X amount of miles, but what they're not telling you is that they tested that blend of oil at idle, occasionally bringing the car up to 2K rpm's. They want to sell you their oil, nothing more. Most car manuals will say change the oil every 5-7K miles for "Normal" driving, and 3K miles for "Extreme Condition Driving". Extreme conditions are pretty much highway driving, getting on onramps, city driving, and anything other than a steady 35 MPH all day, every day. Pretty much, if you start the car and let it run for more than 10 minutes, you fall into the "Extreme Driving" category. Totally unrealistic.

 

Most additives are gimmicks. The best ones are Lucis Oil Stabilizer, Marvel Mystery Oil, and Engine Restore W/CSL. Anything less than $5 per bottle is probably of lesser quality than if you just used straight up oil. Personally I swear by Engine Restore, as I had an engine that would only run on 3 cylinders due to worn piston rings. About 25 miles after adding the Engine Restore the engine would begin to run on 4 cylinders again. It would go like this for at least 250 miles then cut down on 4. I'd add another can of Engine Restore and the same thing would happen, until the rings fell into the oilpan entirely. I pulled the head and found that the piston in cylinder 1 had suffered from horrible lash, and contacted the cylinder, wearing down one side of the piston. There was enormous endplay between the piston and the cylinder.

 

It's cheap, it's easy, change the oil every 3-4K miles and keep your car happy... It's an investment in longevity, and not something you need to skimp out on.

[gathermewool]

For a well-maintained car I don't think changing the oil filter any more than every 10kmi is necessary. The media and casing will go on for a good long while, and, unless you have major contamination issues the media will not really retain anything at all. If you've ever torn open a filter you'll notice that there really isn't much to see in there but a few specs of what ever in the filter pleats.

 

I wouldn't say to trust the claims of any product, but if there is a way to accurately qualify an oil as able to withstand long OCI in your particular car for your particular driving then why wouldn't you extend for as long as possible? The only true to way qualify is via used oil analysis with TBN and TAN. Regardless of how you feel, a UOA, while incredibly limited in so far as where is concerned - particles counted are very small, and does not indicate which TYPE of wear - is a very good tool to determine how well the oil is holding up in your application, as well as other relevant characteristics such as viscosity, flash point, etc. A good UOA will also indicate excessive contamination due to an air leak or possible ingress of coolant into the system.

 

As far as synthetic vs dino goes it's all a matter, again, of your application and needs. Furthermore, synthetic/dino are very general and don't really give much info. Oil base-stock grouping and additive package are far more relevant than what the bottle says. Base stock makes up 80% of the oil, with 20% being additives for anti-wear, dispersants, viscosity index improvers, etc. Most cheaper oils on the market are group II or group II+, which means they're made from dino bones. Group III is made from dino bones, but is processed/refined enough to be considered a synthetic. Group IV and V consist solely of synthesized product. Synthetic is usually a better choice because the base stock is more robust and homogeneous and less prone to degradation when exposed to high temps and levels of contamination.

 

IMHO I believe that normal or severe service has more to do with how much time you spend at temp as opposed to your driving "personality." 5kmi of driving spiritedly on the highway all day long every day is much, much easier on the oil than 5kmi of driving exactly 35 mph 1-2 miles each day to work. While high temperature sheering is an issue, the main killer of oil is fuel dilution, moisture and combustion blow-by, which are much more prevalent when the engine spends the majority of its time in cold service doing short trips.

 

Most additives are exactly what they are, additives. Regardless of what the bottle claims, what is inside the bottle is something and IT has a purpose. Lucas doesn't really do too much but thicken up the oil a bit, which has nothing to do with the oil's ability to perform well. MMO, like Auto-Rx is a synthetic ester-based oil used for tits ability to clean. You don't add MMO or Auto-Rx to allow you to extend your OCI, but to add a bit more cleaning. It offers you the same cleaning action as you would have if you ran an ester-based full-synthetic oil. I don't know what's in Restore, but I've heard mixed reviews. In all honesty, knowing the constituents of an oil or additive doesn't mean anything unless you know what those things do. Most people pick a decently priced, name-brand oil that's on sale and run an (overly) conservative OCI to cover their bases.

 

I wholeheartedly agree with you, Platinum, that it is cheap and easy to do it every 3-4kmi, but in some instance it's entirely wasteful. It makes me cry a little on the inside every time I read about some one who spends $10/qt for a good oil and changes it out every 3-4kmi.

[Platinum_Racing]

I wouldn't spend that much on oil seeing as how I replace it regularly. Honestly, more power to the guys who run synthetic oil, but I personally prefer a good earth oil. I've used synthetic oils, but have also worked on an 830 HP Chevy 454 bored out to 468 in a big block SuperModified that ran on dino oil with no additives. The only additive that engine ever used was Water Wetter in the coolant. That's good stuff! Cars have run on dino oil for years and years with no problems. Some manufacturers also don't recommend using it for the first 10K miles of an engines life, like Cummins for example.

 

I also choose 10-40 for my car. The way I see it, a filter isn't that much money, so it's worth it to just replace it when it's spent.

 

As far as Restore goes, I like it. It coats the cylinder walls with it's magical serum, then after being heated and cooled a few times it supposedly hardens into scratches and imperfections, giving the rings a better surface to seal. It's worked wonders for me in the past, so as a result I get a can of their 4 cylinder formula (Just a smaller size can) either every oil change, or every other oil change. Ever since I saw that car with blown out piston rings run on all 4 after putting in restore I was amazed enough to become a loyal customer. Usually I don't go for "Snake Oil". I have a few nitro R/C cars, and Marvel Mystery Oil works great as after run oil, but I've never tried it in an automotive engine. Just to coat pistons for re installation.

 

I don't know, to each his own I guess.

[mclement]

Thanks for all your input. I'm psyched to have this many people who obviously know their stuff and are willing to share their knowledge. Definitely learned my lesson about checking the oil in between changes, the last thing I need as an engine as toast. FYI, almost all my driving is city which probably doesn't help the oil consumption issue and gives me another reason to change the oil more frequently....

[Platinum_Racing]

No problem.

 

Through our debates/discussions, I think there are several things we all can agree on...

 

1: Check oil regularly

2: Synthetic or dino-oil, always use decent quality

3: All engines consume oil, some faster than others. Your engine in particular sounds fine

4: Platinum_Racing is the man

 

[Jf29]

M