'96 Toy RAV4 Oil Top-ups: Rings or Valve Seals?

Discussion in 'The Garage' started by Guano11, Jul 2, 2013.

  1. Guano11

    Guano11 Behind Bars....

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    1996 RAV4, 2.0L, 196K miles, oil changes every 3-5K, always synthetic.
    FWD 5spd, daily driver, original owner, zero issues otherwise.

    Recently began requiring oil top up, say 1/2qt every 1000-1200 miles or so -- probably in-spec, but it never used a drop between oil changes before. I suspected valve guides or valve seals (occasionally witnessed a puff of tailpipe smoke on start up, but not always). Local independent Japanese car mechanic says he's sure it's the rings, as if to say "They all do that", though he did not inspect the car himself. He recommended trying a can of Restore...."Couldn't hurt". Oil doesn't seem to stay "clean" as long, either, though it never gets tar-black.

    So question to those with experience with this particular motor: Do the rings go despite diligent oil servicing? Light duty on the vehicle; only midway through its 3rd set of tires and still sporting the original clutch. Peering down the oil fill reveals only clean valvetrain parts, no sludge.

    Appreciate any expetise, fellas. Valve seals seem doable, but a ring job is probably over the top for this car....
    #1
  2. k-moe

    k-moe Long timer

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    Either have a leak down test done.....or top up the oil and don't worry about it. The real question you need to ask is, "How much do I want to spend to not need to top up the oil?" Unless compression is waaaay down that engine will run for a very long time before anything will actually need to be done.

    FWIW....the average daily driver is considered to be a "heavy use" vehicle.
    #2
  3. Guano11

    Guano11 Behind Bars....

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    ^^^ I like that rationale. A lot, actually. ^^^
    It's not my nature to have something around that ought to be working better, but makes a lot of sense to run it as-is. Might try the leakdown just to satisfy my own curiosity. Supsect all cylinders pressurize very close to one another.
    #3
  4. CycleDoc59

    CycleDoc59 Wrench Rider

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    Pull all the plugs and look for variation of the
    tip color. If one looks worse than the others,
    that particular cylinder may be the culprit....
    If so, it could be valve seals or rings, as you say,
    on that one cyl.

    If all are the same, it could be still be a bit of wear
    on all cylinders or valve seals. Over those 196K miles, ring
    gap would likely increase, and valve seals would wear,
    harden.

    To find which it may be, run a compression test on a
    cylinder (easiest to do while all plugs are out). For the
    test hold the throttle open. Then put a table spoon of
    motor oil in the plug hole and run the test again. If
    compression increases substantially, the rings are worn,
    and some oil is likely getting past...

    Valve seal leakage often shows up on long down-hill runs
    w/throttle off. The engine vacuum will then pull in oil by
    the seals, and those following will see smoke....

    Me, I'd just remember to add oil...!
    #4
  5. 1911fan

    1911fan Master of the Obvious

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    From the vantage point of ten years as a Toyota service writer, I say this: Don't worry about it, just top it off as needed. Sure, you can find out why it's using oil; my guess is rings as noted above. Start a log of driving type/miles and oil used; my bet is it is using oil on highway miles. The puff of blue smoke on cold starts is likely valve guide seals, and they can be replaced without taking the head off.
    Top it off regular, and check it often so you stay on top of it. Almost 200k miles, it's a rare engine that doesn't use a little oil at this point.


    1911fan
    #5
  6. Guano11

    Guano11 Behind Bars....

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    Thanks for the educated responses, fellas -- very instructive for a guy like me. You've convinced me that just keeping the oil level in check is the most sensible course of action (Guanowife, however, will see that as "It must be about to blow!" so maybe it's time to hand it down to the teenage drivers.....).

    Will pull the plugs at first opportunity & see what they reveal.
    Sounds like there's no point in pouring a can of Engine Restore, either.
    #6
  7. Navin

    Navin Long timer

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    How about switching to a diesel oil like Rotella, maybe a thicker grade too? You might slow it down a bit.
    #7
  8. Tmaximusv

    Tmaximusv Been here awhile

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    Not a Toyota, but my Volvo T5 has a very similar problem and using 15-40 Rotela didn't really solve anything. I have since changed oil and have been topping up with an old bottle of Wally World synthetic. Burning went away but dripping continues. Valve guides is my guess on mine.
    #8
  9. Langanobob

    Langanobob Been here awhile

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    We also have a '96 RAV4 with an oil burning issue. It always burned a little too much but then got really extreme.

    I think it is a valve stem seal problem. I ignored it and just added oil (a lot of oil) but now I think the catalytic converter is clogged as the car is really hurting for power. Compression is ok.

    It now has somewhere around 240,000 miles on it but I think the excessive oil usage started at about 100K and got progressively worse.

    The darn things are really hard and awkward to work on. No room at all. If it's also due for a timing belt change I'd do the valve stem seals at the same time. Otherwise I'd just run it and add oil as needed. Unless it's your wife's or daughter's car in which case they will sooner than later run it out of oil.

    Bob
    #9
  10. boxermoose

    boxermoose Now fully goosed

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    Could also be stuck rings....next time just before you change oil - .drop a teaspoon of marvel mystery oil into each plug hole and leave overnight, or use some Yamaha ring free

    Drop some more in the crankcase, run for a hundred miles and then change oil
    #10
  11. Gillus

    Gillus High Desert Rat

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    Pull the plugs, look at the edges of the pistons against the bore If they are washed around the edges or the carbon is washed off around the edges it most likely is the oil scraper rings. The compression rings can be fine and compression good but oil rings can be stuck or worn.

    If the pistons are washed, stop driving it immediately other than to go to the store to get a qt of oil, top it off like 1911fan suggested then run the wheels of it. :lol3
    #11