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found engine oil leak but not sure where it's from

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by working1, Dec 24, 2014.

  1. working1

    working1 Active Member

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    I was changing the ATF fluid for the first time and noticed a film of oil on the backside of the engine right above the oil filter. It appears to be from a sensor, but, not sure what it is. Anyone know or seen this before?

    prius-3.jpg
    prius-4.jpg
    prius-1.jpg prius-2.jpg
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The third photo seems to show the oil leak is coming from a point at least as high as the exhaust manifold. Who changes the engine oil, and is it possible that person spilled some oil during the process, which dripped down the back side of the engine?

    You can apply some degreaser to the area, wash off with water, and see if the oil stain reappears.

    Or, if you are sure the oil stain is not due to a maintenance error, and assuming your car is still covered under the 5 year/60K mile powertrain warranty, let your local Toyota dealer figure it out.
     
  3. nedim

    nedim Junior Member

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    It could be from one of the sensors there or it could be the seal for the timing chain cover.
     
  4. working1

    working1 Active Member

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    I can rule out oil spilled during an oil change since I've done it myself since new and photo shows a clean area back of the oil cap. I closer look does show the leak is likely above this area. Attached is one photo from the top. Car has over 81K miles so likely not covered by warranty?

    prius2-1.jpg
    prius2-5.jpg
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    OK, since you would have to pay for the repair yourself I suggest you start by cleaning off the oil stain with engine degreaser and hose down with water. Then see how long it takes for the oil stain to reappear, maybe it will be easier for you to locate its source when you start fresh.
     
  6. bisco

    bisco cookie crumbler

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    :(no warranty. are you getting any oil on the ground where you park overnight?
     
    #6 bisco, Dec 24, 2014
    Last edited: Dec 24, 2014
  7. JC91006

    JC91006 Senior Member

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    Does the car use much oil in between changes?
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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  9. working1

    working1 Active Member

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    There has not been any noticeable oil loss between changes and no oil dripping on the ground. The area of the leak is not easy to see and the bottom engine panel needs removed to access it. Others could have the same issue and never see it. Plan is to degrease as suggested then use a digital inspection camera to monitor and track down the source.
     
  10. JC91006

    JC91006 Senior Member

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    No noticeable loss of oil, car is out of warranty, there doesn't seem to be any driving issues....I would just continue on my day.
     
  11. nedim

    nedim Junior Member

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    From the pictures I can tell it is not coming from the engine block or cylinder head or valve cover. I am pretty sure that it is coming from the seal between the timing cover and the block/cylinder head.
    I will attach some photo's so you can see what exactly I mean.

    I doubt it that it is from the two sensors on the timing cover. The bottom one has an o-ring inside the timing cover. The other bigger one on top of it is for the crank position which has a metal gasket.

    That timing cover is sealed with some kind of brown/grey silicone not with a gasket. I was pretty worried when I was planning to close it.

    Oil leak forum member
     
  12. The Critic

    The Critic Resident Critic

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    Check the area around the timing cover, that may be the leak.

    If that's the case, I would probably turn a blind eye to it. It's not a cheap fix as it requires the engine to come out.
     
  13. edthefox5

    edthefox5 Senior Member

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    Is the black connector the crankshaft sensor?
    Leaks at that sensor are not uncommon.
    If timing cover suspect, get a socket wrench
    and check the bolts in that area. See if any
    are egregiously loose.
     
  14. mbtans

    mbtans Junior Member

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    I'm at the dealer right now and they discovered oil on the same spots you described - they said mine is a leak from the timing chain cover and the quoted $980 for the work.

    My background: I haven't seen any leaks on my driveway, haven't noticed oil consumption between changes, and had the transmission oil changed about six months ago.

    Working1, what did you do about yours?
     
  15. JC91006

    JC91006 Senior Member

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    I would refer to post #10
     
  16. xliderider

    xliderider Senior Member

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    Are you within your 5 yr/60,000 mile powertrain warranty? If so, it's covered, if it's the timing chain cover seal.

    My dealer quoted $1700 for the job, but I had it done no charge after I reminded them that it is under warranty.
     
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    FWIW, there was someone else here with a leak from that cover, the dealership was asking $1700 (US), to reseal it. Ended up no charge, under warranty.

    But yeah, minor leakage out of warranty, I'd just keep an eye on it.
     
  18. xliderider

    xliderider Senior Member

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    Speak of the devil. :whistle:
     
    Mendel Leisk likes this.
  19. The Critic

    The Critic Resident Critic

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    Book time to reseal the timing cover is 14.2 hours, $980 to do it is a screamin' deal. I would take it.


    iPhone ?
     
  20. prscht

    prscht Junior Member

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    I had a similar leak on a Prius v wagon that uses the same engine, at around 40K miles. in my case the leak came from the timing chain tensioner cover gasket, which is the diamond-shaped rusty-looking cover secured with two nuts, visible in pictures 1 and 3 of the OP's first comment. in those pictures the cover is partially obscured by the blue tape on the sensor wire.

    This cover is at the same level as the exhaust manifold, which could be why no sign of oil leak existed above this height on the OP's engine, as was in my case. the gasket on my car was replaced under the 60K mile powertrain warranty, and the leak has not returned now at 47K miles.
     
    #20 prscht, May 22, 2015
    Last edited: May 22, 2015