Correct Oil Level

[Todd Foggoa]

I just had my 2002 Impreza Outback Sport in for a 48000Km check up at my
dealer. All other maintence I have not gone to my dealer and I probably
won't go back.

When I got the car home after the service I checked the oil and it looked
way too full. I figured it must be wrong and I'll let the car cool, even
though it shouldn't matter. A couple of hours later it was still way above
the notch in the dipstick. On my dipstick I have 2 holes through the dipstick
and a notch a little higher. The manual clearly states to fill a cold
engine to the top hole (Full mark) and when the engine is warm the level
may rise to the notch. I looked at my invoice and the dealer had charged
me for 5 liters of oil when the manual says the oil capacity is 4 liters.
The dealer had clearly over filled the oil.

I am quite disappointed that a subaru dealer doesn't even known how much
oil to put in their cars. I expect much more from a dealer.

I took the car back to the dealer the next day so they could drain off
some oil and fill it to the full mark. They said they have always filled
cars to the notch and that nothing would happen with the extra oil in there.

Does anyone know what running with too much oil can do to the engine? over
the long term? I'm thinking the increased oil pressure may cause seals to
blow.

-Todd

 

[Rick Courtright]

Does anyone know what running with too much oil can do to the engine? over
the long term? I'm thinking the increased oil pressure may cause seals to

Hi,

I've heard the "excess oil pressure" and "blowing seals" story for
years, but have found little to support either of those ideas. The oil
pressure's a function of what the pump design and check/relief valves
allow with a given viscosity oil, modified by heat and engine wear among
other things. Ever notice that there's little, if any, noticeable
difference between the pressure with a full sump and one that's a
quart/litre low?

OTOH, there IS a serious problem with overfilling that's pretty well
documented. That's the problem of the oil level being high enough the
crank spins around in the oil like an eggbeater and causes the oil to
foam up. Now you're trying to pump aereated oil under pressure and it
"collapses" because of the air, so you lose pressure and lubrication.

I don't know if one quart/litre is enough to cause this problem with a
Subie engine. Usually a quarter to half qt/l won't make a bit of
difference in most engines, but it's probably best to drain a little off
in your case.

Rick

 

[Tony Hwang]

Hi,
The way I see it is, between two holes is usual operating range of
oil level. The notch is maximum level allowed. New filter will soak up
oil little bit, so to me it is OK unless it is way over the notch.
Tony

 

[John]

Check the level before you start the car for the day. This will give you an
exact level...
Does the manual state anything else about adding a quart if the filter is
changed?
IIRC, some manuals have two amounts, one without the filter change and one
without

 

[John]

I've heard the "excess oil pressure" and "blowing seals" story for

years, but have found little to support either of those ideas

usually occurs on higher mileage or older engines where the seals are
beginning to break down

 

[Todd Foggoa]

Hi,
The way I see it is, between two holes is usual operating range of
oil level. The notch is maximum level allowed. New filter will soak up
oil little bit, so to me it is OK unless it is way over the notch.

I checked the oil after the car had been running so there would already be
some amount of oil in the new filter. The manual clearly states that the
notch is where the oil level may rise to when the engine is hot. It is not
a maximum when the engine is cold.

-Todd

 

[Todd Foggoa]

Check the level before you start the car for the day. This will give you an
exact level...

I agree, and in this case I would expect it to read somewhere between the
low hole and the full hole, not anywhere near the notch, or in my case
above the notch.

Does the manual state anything else about adding a quart if the filter is
changed?
IIRC, some manuals have two amounts, one without the filter change and one
without

My manual doesn't say anything about adding an extra quart when doing an
oil change. However in my case the car had been running so the oil filter
would have had some in it.

-Todd

 

[John Eyles]

New filter will soak up

oil little bit, so to me it is OK unless it is way over the notch.

Not much if you use the cool trick I just learned - fill the
new filter with oil before you screw it on (if, like on my
engine, it installs gasket-up). Sigiificantly reduces that
bad time when you first start the engine after an oil change
and there's virtually no oil pressure.

John

 

[John Eyles]

usually occurs on higher mileage or older engines where the seals are

beginning to break down

Speaking of which, my '97 Legacy 2.5 seems to be leaking from
the rear main seal (or possibly somewhere else nearby).

But I'm not losing much oil at all, and I'm sure it's a very
expensive repair.

Is the fact that it's leaking SOME an indicator that a
catastrophic failure is much more likely ? Or could I
safely wait until the oil loss rate becomes more than a
minor annoyance ?

Thanks, John

 

[Rick Courtright]

Is the fact that it's leaking SOME an indicator that a
catastrophic failure is much more likely ? Or could I

Hi,

In my experience, leaking front or rear main seals typically start to
make a HUGE mess before they finally fail completely. A drop every few
days is just a reminder to start saving your money, whereas a small
puddle (1" or so?) every day says make the call and get your mechanic
scheduled for the repair if you're not your own "wrench." A bigger
puddle (2" or so???) every day says to me you should check your oil
level religiously before driving until you get it fixed!

How expensive the repair is depends on what transmission you have, among
other factors, cuz if you have a stick, leaking oil from a rear main
seal will usually get on the clutch disc and call for replacement.

Rick

 

[Carl 1 Lucky Texan]

Double check your PCV valve and hoses. If it's not working well it'll
increase/cause oil leaks.

Carl
1 Lucky Texan

 

[Verbs Under My Gel]

I just had my 2002 Impreza Outback Sport in for a 48000Km check up at my
dealer. All other maintence I have not gone to my dealer and I probably
won't go back.

When I got the car home after the service I checked the oil and it looked
way too full. I figured it must be wrong and I'll let the car cool, even
though it shouldn't matter. A couple of hours later it was still way above
the notch in the dipstick. On my dipstick I have 2 holes through the dipstick
and a notch a little higher. The manual clearly states to fill a cold
engine to the top hole (Full mark) and when the engine is warm the level
may rise to the notch. I looked at my invoice and the dealer had charged
me for 5 liters of oil when the manual says the oil capacity is 4 liters.
The dealer had clearly over filled the oil.

I am quite disappointed that a subaru dealer doesn't even known how much
oil to put in their cars. I expect much more from a dealer.

I took the car back to the dealer the next day so they could drain off
some oil and fill it to the full mark. They said they have always filled
cars to the notch and that nothing would happen with the extra oil in there.

Does anyone know what running with too much oil can do to the engine? over
the long term? I'm thinking the increased oil pressure may cause seals to
blow.

-Todd

Todd,

I had a similar experience when I took my 2002 Legacy GT in for its
complementary 3000 mile oil service. When I checked the oil the next
morning (cold engine), it was quite a ways _beyond_ the notch! I saw
this as an opportunity to fill the crank case with the Mobil1 that I
had recently obtained for a "song" at Wal Mart. Here are a couple of
things to consider regarding "overfilled" sumps in these opposed
engines, and in engines in general:

More oil != greater oil pressure. Oil pressure is a function of the
oil pump, oil viscosity (temperature dependent), engine RPM, and
bearing clearances (did I leave anything out?)

In some (many?) engine designs, overfilling the sump will allow the
crankshaft webs to come in contact with the oil. This may or may not
whip the oil into a foam. Foam does not pump well, nor does it
lubricate well. On the Subaru engines, do to their opposed design,
the crank shaft sits much higher above the oil in the sump, so you'd
have to _really_ overfill for the webs to come in contact with the oil
in the sump.

Happy motoring!

 

[John Eyles]

Double check your PCV valve and hoses. If it's not working well it'll

increase/cause oil leaks.

Oh yes, good idea, thanks. Haven't ever done anything with that
stuff.

John

 

[S]

Hi Todd, John, All!

Check the level before you start the car for the day. This will give you an
exact level...
Does the manual state anything else about adding a quart if the filter is
changed?
IIRC, some manuals have two amounts, one without the filter change and one
without

The tiny filter used on the Subaru engines can't possibly hold more
than a cup of oil; it just doesn't enclose that much volume! I always
put in 4 quarts (a bit less than 4 liters; 1 qt = .95 l), whether I
change the filter or not. 5 liters seems a bit excessive, tho; I'd be
tempted to take it back and make 'em do it again. But then they'd
probably find a way to f___ something else up

Todd, the dipstick on the subaru engines takes a bit of technique to
get consistent readings. I like to take levels with the engine at
operating temperature, but if you prefer to do it cold that's fine
too, as long as you always do it that way.

The procedure that works well for me follows:
Open hood and withdraw dipstick, wipe clean, and re-insert ~1/2 way.
Wait a couple minutes (while fuel pumps or whatever).
Insert stick all of the way, immediately withdraw and take reading.

If you subsequently re-insert the stick and pull without waiting, you
will probably get a higher than normal reading. I assume that this is
because withdrawing the dipstick pulls some oil up into the tube,
which then finds its way onto the stick, confusing the level
indication. Whatever, try the above procedure and see if it doesn't
produce more consistent readings for you.

ByeBye! S.

Steve Jernigan KG0MB
Laboratory Manager
Microelectronics Research
University of Colorado
(719) 262-3101