engine oil level

[dsmith]

2000 outback just bought. inconsistent and hard to read engine oil levels. any suggestions?

[The Dude]

2000 outback just bought. inconsistent and hard to read engine oil levels. any suggestions?

A well known complaint among Subaru owners. The following may help a little:

 

Check the oil level in the morning, before starting the car

Check both sides of the dipstick. One side is usually more dependable

Repeat the process several times to be sure that you have an accurate reading

 

Fortunately, Subarus typically burn very little oil.

[99obw]

Make sure the location the car is parked when you check it is perfectly level. Our driveway is slightly sloped where the cars are parked and it makes an accurate read impossible. I find it easiest when the car is fully warmed up, when cold it seems to do goofy things on the dipstick.

[powderhound]

There is a graphic on top of the dipstick that must be facing the correct direction. Read the owners manual I cant remember...I think the side with the little oil drip is supposed to point to the right. Also make sure you're checking the oil at consistent situations...ie always check it cold in the morning or always check it at a gas up. It is true about two sides giving different readings...I always go with the lower side. It is true that subies burn little oil but they leak.

[sprintman]

I agree. Leave o'night on dead level surface and read the backside of dipstick. Owners manual covers this from memory.

[Commuter]

Yeah, they are fussy to read.

 

I prefer to read mine after it has sat overnight.

 

My theory - the twists and turns in the tube and the dipstick itself pulls oil up onto the inside of the tube. You pull the dipstick, wipe it off, then reinsert it. As you do, you are smearing oil back on it. More smear as you pull it out to view the level.

 

My ex's 99 Honda Odyssey... If it has sat at all, you can just pull the dipstick, read it a clear as can be, reinsert and done. Wiping not even necessary.

 

Commuter

[Setright]

It's a drawback of the flat boxer design. I prefer to read it cold, on level ground. If it seems to have dropped suddenly, take for a short drive, let cool, check again. Sometimes oil just stays in the rocker covers...

[Tiny Clark]

Sand off the dark surface with some fine grit sandpaper. The level will be easier to read.

[erhayes]

I've found that if you SLOWLY remove the stick and don't reinsert it for several minutes I get a good reading. If you pull the stick fast you pull oil into the guide tube. If you wait a couple of minutes any oil in the guide tube will drain back into the sump. ed

[slo5oh]

my '98 doesn't have that problem

 

I pull (fast, but not at race speeds) wipe, reinsert, pull again and can always read it just fine. The trick is to check both sides... one side always gets smeared. Look for the lowest level that is covered completely with oil, thats where your level is. My driveway is on a about a 5% slope uphill and I always get consistant reads, Hot, cold, 1000 miles or 5000 miles... at 10k I was about a quart down so I switched to 15-50 wt. mobil 1. Really burning 1 qt in 10k is low usage, but I have 110k now and I think i'm adding about 4k a month.

[Setright]

My old Legacy would use between 1 and 2 quarts for every 6000 miles. Nothing to worry about. So 1 every 10k sounds like a new engine! Mileage was well over 150k.

[dsmith]

 

 

Engine oil levels

 

Firstly, thank you to all the oil level obsessive Subaru owners who responded to my question. It inspired me to look into the problem in some detail, including some bench tests. Anyway, it appears there are several sources of the problem of getting good oil level readings on my 2000 Outback.

 

The dipstick goes into the oil at about a 30degree angle instead of 90 degrees. This means that a change of ¼ inch in real oil level shows on the dipstick as almost ½ inch. This means that any change is exaggerated.

 

The dipstick contacts the oil level at the extreme left side of the oil pan which means that if the car is off level, the reading will vary more than if the dip stick were closer to the center of the pan.

 

Because of the 30 degree angle, surface tension pulls the oil down on the top side of the dip stick and up on the underside. This can result in a ½ inch difference between the two sides of the stick. You can verify all of these things by sticking a knife blade into a glass of water.

 

Then, there is the problem that the dipstick tube goes below the oil level which means the bottom on the tube is always full of oil. This results in uneven surface tension effects inside the tube, complicated by the surface tension on the dipstick. This would not be so much of a problem if the tube were not also sealed at the top by the Oring on the dipstick This means that there is a trapped column of air inside the tube. So, when the engine is shut off, the air in the tube begins to cool and draws oil up into the tube. On the Outback, this pulls the oil up the dipstick by about 2 inches overnight, and you can’t get a reading on the first try in the morning. Also, when you push the dipstick fully into the tube, the O ring works like a piston and compresses the air enough to push the oil level down by up to ½ inch. But, the real problem is that when you pull the dipstick out, the piston effect pulls the oil level up, resulting in too high a reading which varies with how fast the dipstick is pulled.

 

So, what can the oil level obsessed driver do? My own solution was to drill a small hole through the plastic handle on the dipstick to below the O ring. This prevents the air being trapped, and you can get a good reading after the car has sat overnight. The car must still always be more level than most cars because the changes are exaggerated as noted above. I do not necessarily recommend this because you also have to put a filter over the drilled hole to prevent dust being drawn into the oil.

 

Another approach would be to pull the dip stick out for a few minutes to let the oil drain out of the tube, then check the oil by pushing the dip stick down just until the O ring contacts. As, noted above, pushing it right down can push or pull the oil level in the tube.

 

 

Sorry for the long explanation, but I think all of these things contribute. Thanks again for your replies. D. Smith

[forester2002s]

Thank dsmith for that write-up. That explains a lot.

 

Are any Subaru design engineers reading this?

[Setright]

Are you certain the tube actually penetrates the oil level??

 

 

I find that I get a consistent reading if I let the car cool on a level surface overnight, pull the stick, wipe it clean, insert all the way and pull it out.

[friendly_jacek]

 

 

Engine oil levels

 

Firstly, thank you to all the oil level obsessive Subaru owners who responded to my question. It inspired me to look into the problem in some detail, including some bench tests. Anyway, it appears there are several sources of the problem of getting good oil level readings on my 2000 Outback.

 

The dipstick goes into the oil at about a 30degree angle instead of 90 degrees. This means that a change of ¼ inch in real oil level shows on the dipstick as almost ½ inch. This means that any change is exaggerated.

 

The dipstick contacts the oil level at the extreme left side of the oil pan which means that if the car is off level, the reading will vary more than if the dip stick were closer to the center of the pan.

 

Because of the 30 degree angle, surface tension pulls the oil down on the top side of the dip stick and up on the underside. This can result in a ½ inch difference between the two sides of the stick. You can verify all of these things by sticking a knife blade into a glass of water.

 

Then, there is the problem that the dipstick tube goes below the oil level which means the bottom on the tube is always full of oil. This results in uneven surface tension effects inside the tube, complicated by the surface tension on the dipstick. This would not be so much of a problem if the tube were not also sealed at the top by the Oring on the dipstick This means that there is a trapped column of air inside the tube. So, when the engine is shut off, the air in the tube begins to cool and draws oil up into the tube. On the Outback, this pulls the oil up the dipstick by about 2 inches overnight, and you can’t get a reading on the first try in the morning. Also, when you push the dipstick fully into the tube, the O ring works like a piston and compresses the air enough to push the oil level down by up to ½ inch. But, the real problem is that when you pull the dipstick out, the piston effect pulls the oil level up, resulting in too high a reading which varies with how fast the dipstick is pulled.

 

So, what can the oil level obsessed driver do? My own solution was to drill a small hole through the plastic handle on the dipstick to below the O ring. This prevents the air being trapped, and you can get a good reading after the car has sat overnight. The car must still always be more level than most cars because the changes are exaggerated as noted above. I do not necessarily recommend this because you also have to put a filter over the drilled hole to prevent dust being drawn into the oil.

 

Another approach would be to pull the dip stick out for a few minutes to let the oil drain out of the tube, then check the oil by pushing the dip stick down just until the O ring contacts. As, noted above, pushing it right down can push or pull the oil level in the tube.

 

 

Sorry for the long explanation, but I think all of these things contribute. Thanks again for your replies. D. Smith

So, basically you are saying that it is physically imposible to obtain a correct oil level on a subaru. Well, I will live with my artifactual levels :-)

[99obw]

I will reiterate that I get consistent reads when hot and level. When the oil is thin all of these symtoms seem to dissapear. YMMV.

[dsmith]

Hi oil fans:Setright asked if I were sure that the tube penetrates the oil level. It does on my 2000 Outback. This can be checked by blowing into the top of the tube so you can hear the oil bubbling. Perhaps oil is not your favourite flavour, so you could also use a short piece of hose or pipe. Penetration can also be verified by measuring the dip stick and the outside of the tube.

 

Best regards. D. Smith

[Setright]

Okay, very creative. However, on my 1990 Legacy I replace the oil pan....and could see clearly that the tube did not reach below the level.

 

Maybe your engine is overfilled??

[sios]

Maybe your engine is overfilled??

Chiming in, on that note... I've had trouble checking oil level of the '04 OBS. Obviously has one of those difficult to read dipsticks, as others here have already pointed out.

 

I hadn't looked at the actual tube itself, down by the oil pan, before. I see now how it does bend and go in at an angle. The stick also has a notch out, above the Full mark. I probably should look into this, but I'd guess it is an overfill or hot oil mark. With the angling I'm thinking maybe it wouldn't be too big a difference in levels between the low, full, and overfilled (hot) marks, yet apparently about a quart from low to full like most dipsticks I knew of in the past.

 

After changing my original (new car) oil out at 1442 miles with Mobil1 I noticed I might have gone over the Full mark by a little bit. Drained half quart out and it looks like it is at or below full, just that the oil on the stick is very different on both sides. So I was glad to read about the troubles with that here and maybe there's a better way to check it. I added 4.25 quarts (filter changed too), approximately, judging by the 5 quart jug's visible level gauge. OM calls for only 4.2 Qts, so it's conceivable there was some oil left behind during the drain. It's just very difficult to tell what the dipstick is telling me, would be nice if the manual told how much to add when it shows to be right at low.

 

Anyway, I'll run it a while with mine somewhere between low and full until I can figure out where Full really is.

[Setright]

The low and high marks are one litre/quart apart according to the manuals. I find that half that amount often yields a good result.

[Tiny Clark]

What Setright said, betwixt the marks.

[dsmith]

Hi Setright:

 

It could be that the 1990 is different. I have checked , and mine is not overfull. On the 2000, the tube hits the outside of the oilpan below the normal oil level.The blow in the tube may still be the best test. I gather you are in Denmark. I was there last month, and your excellent brews would certainly wash the oil taste out of your mouth. Thanks again for response. Dave

smith

[Setright]

No..time..to..write....chugging Carlsberg...!

 

Jokes aside, I now own a 2000MY Impreza 2.0, and although I haven't checked the dipstick tube location, I have not had any trouble getting a consistent reading on the dipstick itself.

 

But do have years of Sube experience behind me :-)

[forester2002s]

I've also noticed that little notch on the dipstick, above the 'full' mark (2002 Forester).

 

I get an oil-smeared dipstick (both sides) regardless of how I pull the dipstick: slow; fast; hot; cold; overnight or at gas-station. It usually takes a few tries and wipes, to guess at the level.

 

Maybe the oil level isn't too critical, as long as it is above the starvation level???

[Setright]

The notch is supposed to indicate the maximum hot mark.