Correct Oil Level

Discussion in 'General Motoring' started by Todd Foggoa, Sep 29, 2003.

  1. Todd Foggoa

    Todd Foggoa Guest

    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

    Todd Foggoa, Sep 29, 2003
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  2. 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 Courtright, Sep 29, 2003
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  3. Todd Foggoa

    Tony Hwang Guest

    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 Hwang, Sep 30, 2003
  4. Todd Foggoa

    John Guest

    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
    IIRC, some manuals have two amounts, one without the filter change and one
    John, Sep 30, 2003
  5. Todd Foggoa

    John Guest

    I've heard the "excess oil pressure" and "blowing seals" story for
    usually occurs on higher mileage or older engines where the seals are
    beginning to break down
    John, Sep 30, 2003
  6. Todd Foggoa

    Todd Foggoa Guest

    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 Foggoa, Sep 30, 2003
  7. Todd Foggoa

    Todd Foggoa Guest

    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.
    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 Foggoa, Sep 30, 2003
  8. Todd Foggoa

    John Eyles Guest

    New filter will soak up
    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 Eyles, Sep 30, 2003
  9. Todd Foggoa

    John Eyles Guest

    usually occurs on higher mileage or older engines where the seals are
    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
    John Eyles, Sep 30, 2003
  10. 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 Courtright, Sep 30, 2003
  11. Double check your PCV valve and hoses. If it's not working well it'll
    increase/cause oil leaks.

    1 Lucky Texan
    Carl 1 Lucky Texan, Oct 1, 2003
  12. 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!
    Verbs Under My Gel, Oct 1, 2003
  13. Todd Foggoa

    John Eyles Guest

    Double check your PCV valve and hoses. If it's not working well it'll
    Oh yes, good idea, thanks. Haven't ever done anything with that

    John Eyles, Oct 1, 2003
  14. Todd Foggoa

    S Guest

    Hi Todd, John, All!

    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 :p

    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
    S, Oct 1, 2003
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