oil overfilled?

Discussion in 'General Motoring' started by thestick, Apr 23, 2005.

  1. thestick

    thestick Guest

    Had the oil in my 2001 Forester changed at the dealer today. I brought
    4qts with me. The tech said it took 4.7 and I would be stating almost a
    qt low. I said the manual says 4.2 and that I would add the .2 later.
    He insisted he was right so I let him add the extra.

    Later, I checked the level and found it to be 1/4 inch over the full
    mark on the dipstick. Should I remove the excess? Will it do any
    damage as is?
    thestick, Apr 23, 2005
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  2. thestick

    Edward Hayes Guest

    The correct fill is 4.2 quarts and that brings me to the full hole.
    Your not over filled if when the oil is checked HOT that it is NOT
    over the notch above the full hole. Ed
    Edward Hayes, Apr 23, 2005
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  3. thestick

    l.lichtman Guest

    But, part of the question remains unanswered: will overfilling the oil
    sump harm the engine? I don't think so, but I am willing to be
    corrected. As far as I know, the extra oil may be dissipated, somehow,
    but I don't see how it could harm anything, except, maybe, the
    l.lichtman, Apr 23, 2005
  4. The story in the old days was that, if the level were high enough to be
    'beat into foam' by the crankshaft the oil pump wouldn't be able to pump
    the foam and you'd have oil starvation. I suspect with newer oil
    formulations and having the pickup for the oil low in the sump, it might
    be difficult nowadays to get into that kinda trouble - not impossible -
    just unlikely if you're slightly overfilled.

    Carl 1 Lucky Texan, Apr 23, 2005
  5. Hi,

    Is that hot or cold? If hot, it sounds "just about perfect" (see Ed's
    description of "hot" mark) and if it's cold, it's a tiny bit overfilled,
    but not enough to worry about (see Carl's description of foaming--still
    potentially as much a problem as it ever was if grossly overfilled, but
    your description doesn't raise any red flags.) Overfilling by the
    dealers seems to be a common thing--I always do my own oil changes to
    maintain control over all aspects: brand, weight, amount, but looking
    thru the service records of my Toyota which was dealer maintained
    exclusively prior to its coming to live at my house, sometimes an oil
    change was charged by the quart, often at 5 qts in a 4.5 qt engine (did
    they keep a half qt, or just pour it in?), other times it was "one unit,
    6 cyl" so they probably just dialed a figure on the dispensing hose and
    let 'er rip. Regardless, that car's at 227k miles right now with no
    known adverse effects. So I wouldn't worry about the Subie...

    Rick Courtright, Apr 23, 2005
  6. thestick

    Michael Guest

    I did this when i changed the oil in my wrx. My issue was the car was not
    perfectly level when i changed it. So i added more. I had about that.. 1/4
    over the full line ,i did drain mine down. To much oil can cause excess
    pressure in the crankcase. Damage gaskets and seals and cause leaks. Like
    the rear main seal, oil pan gaskets. And if its way to high the crankshaft
    will be turning in the oil and that will cause more load on the engine, poor
    milage and pre-mature wear.
    Michael, Apr 23, 2005
  7. thestick

    remco Guest

    I did this when i changed the oil in my wrx. My issue was the car was not
    Totally agree -- the extra pressure may not do damage you notice right now
    but in the future.
    I woulnd't take the risk - draining some of the oil is easy.
    remco, Apr 23, 2005
  8. Michael,

    I hate to be skeptical, but I've been spinning wrenches for a LOT of
    years (scary close to a half century), and nobody's ever been able to
    prove this "too much pressure" thing to me: the oil pump doesn't create
    more oil pressure just cuz there's a bit more oil, and any air pressure
    buildup is taken off by the PCV system (or the old road draft system for
    those who've been around long enough to remember.) The engine's
    crankcase is NOT a sealed system with no pressure relief designed in. If
    it were, your engine would probably last about 15 minutes before
    self-destruction. Methinks that "excess pressure" thing's an old wive's
    tale that needs to be put to rest.

    And the crank turning in the oil isn't going to cause enough drag to
    make a difference. What CAN happen (assuming the oil level's grossly
    overfilled, which a quarter or even half quart in a car engine's NOT
    gonna be) is that the crank will churn the oil, causing foaming. "Foamy"
    oil doesn't lubricate well, causing lowered oil pressure and a lack of
    lubrication at critical points, including seals, which CAN cause the
    seal damage and engine wear you mentioned.

    Maybe you can elaborate on what I've missed? I'm willing to learn
    something new.

    Rick Courtright, Apr 23, 2005
  9. thestick

    thestick Guest

    I checked it again this morning. It's about half way between the cold
    full hole and the hot full notch.
    So I guess I'll leave it as is.

    Rick Courtright wrote:
    thestick, Apr 23, 2005
  10. thestick

    Edward Hayes Guest

    Your just fine. If like I said it's not over the notch when hot then
    Subaru says good.
    Edward Hayes, Apr 23, 2005
  11. thestick

    CompUser Guest


    First wife blew the diaphragm in the oil send
    unit, by overfilling by less than a quart, on one
    of my cars.

    I've never seen a baby born, but I'd be a fool to
    claim that proves it never happens ;-)
    CompUser, Apr 24, 2005
  12. thestick

    Michael Guest

    Maybe this makes sense.. if there is to much oil in the crankcase it takes
    up more space, leaving less space for the air. Same ammount of air being
    forced in a smaller space will make more pressure. The pvc, old breather
    system can only relieve so much. I rebuilt a chevy 327 and a Ford 302. The
    327 was out of a 69 impala i put in a 71 nova. The 302 was a 72 in a Bronco.
    I remember a few times while working on them having the breathers blow out
    of the valve cover and the dipstick pop out.This has nothing to do with to
    much oil but to much pressure built up from turning it over alot and it
    couldn't relive it. So the system pcv is ok under normal conditions,but to
    much oil, to much pressure it cant relieve properly and could blow out
    seals, gaskets. The extra pressure has to go somewhere. And if you get in a
    pool and try to walk, how much more effort do you use then out of the water
    ? Any extra load on the rotating assembly will affect milage, wear and
    Michael, Apr 24, 2005
  13. thestick

    jabario Guest

    I think the whole point is "how overfilled"? Four ounces will make no
    difference. Do you keep exact track of how much oil isremoved? If not
    you may overfill. Four quarts probably will!!! Why are some of you so
    anal? Will the roof rack fail w 101 lbs?
    jabario, Apr 24, 2005
  14. Yes, I understand the concept. But did you blow things out of your
    engines cuz you overfilled them with oil? And if so, how far were you

    I've seen the same thing happen you've described, but there was a much
    more serious problem than a little too much oil! (And with all due
    respect to home garage builders, the problems I saw DIDN'T occur in
    professionally built engines. Hmmmm....) Small block Fords and Chevies
    can take a LOT of hotrodding before they start tearing themselves up, IF
    they're done right. Blowing a dipstick out sounds like an extreme
    case--blowby from improperly installed rings, clogged oil return
    galleries, something like that was creating an incredible amount of
    excess AND unrelieved crankcase pressure. Simple pumping pressures from
    the pistons are pretty unlikely to build the kind of pressure you've
    described if all the venting systems are operational (remember that as
    one piston comes down, adding pressure, another is going up, relieving
    it, so it's not quite as straightforward a system as a compressor
    dumping all its output to a holding tank.) I've seen such engines
    pulling close to 400 hp on a dyno when I used to hang with the racing
    crowd, which is close to double factory numbers (and they're capable of
    even more), and they didn't blow seals--everything else would break
    quickly, but that's from overstressing parts, not crankcase pressure.

    And, as you said, your engines were far from stock, so I'm still open to
    seeing a current engine in good shape develop the kind of crankcase
    pressures required to blow seals without GROSSLY overfilling with oil.
    As another poster put it, the fact I haven't seen it doesn't mean it
    doesn't occur, but I've seen and been in too many discussions with
    engineering/builder types and busted enough knuckles getting up close
    and personal with engines to believe it's the problem people think it

    Rick Courtright, Apr 24, 2005
  15. Speaking from experience with '78 Honda Civic, working on a car with
    valve covers and oil pans off, over several weekends, possibly even
    outdoors, can cause a lot of 'gummy residue' to develop. In my case it
    cause the oil pressure releif valve to not do it's very descriptive
    title. It blew the through the oil filter gasket.

    Again, given what we were told - which of course is all we have here on
    a usenet group, I feel (and Rick's opinion is probably worth at least
    100 times mine) you're OK.

    As for CAN bad things happen given COMPLETELY different circumstances?
    well - H3LL YEAH!!!

    Carl 1 Lucky Texan, Apr 24, 2005
  16. thestick

    thestick Guest

    Since the overfill is in ounces and not more, I'm just gonna leave it as


    Carl 1 Lucky Texan wrote:
    thestick, Apr 25, 2005
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