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Sudden engine oil loss

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Marathon Jon, Dec 18, 2014.

  1. Marathon Jon

    Marathon Jon New Member

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    Prius Gen III 96K miles indicated 'oil pressure low' 2K after last oil change. Fortunately we were only a mile from home and were able to drive it home on battery charge. We exclusively use synthetic Mobil 1 0W-20 oil. The oil pan bolt was dry, and it appears the leak is coming from somewhere above the oil filter canister, which I verified being seated and tight. After the engine cooled, I drained the remaining oil (about 3/4 quart) and removed the oil filter canister to check the O-ring seating and integrity of the filter. All appeared normal. After reinstalling drain plug and filter, I slowly put in 3 quarts oil to minimum oil level indication on dipstick. Started engine and ran it for 1 minute and checked for leaks -- no leaks. Turned off engine and allowed the car to sit overnight. The oil level remained unchanged the next morning. I started engine and let it run for two minutes this time, at which time it started leaking rapidly (fortunately I kept the oil catch pan underneath the car). So the oil leaks when the oil pressure rises with warming engine. Any ideas on what I should check to determine the cause?
     
    #1 Marathon Jon, Dec 18, 2014
  2. JC91006

    JC91006 Senior Member

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    If you are positive that the oil filter is seated properly and tightened, you'll have to go to Toyota to get a proper diagnostic. It sounds a bit weird from your description of it leaking rapidly after running for 2 minutes during warm up. If this occurred everytime during startup for 2000 miles, you should have gotten a low oil warning a looooong time ago.
     
    #2 JC91006, Dec 19, 2014
  3. Yakoma

    Yakoma Active Member

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    Ouch...I speculate that you have a punctured or cross-threaded oil filter.
     
    #3 Yakoma, Dec 19, 2014
  4. frodoz737

    frodoz737 Top Wrench

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    As you stated the leak is somewhere above the oil filter canister, get yourself a good light, inspection mirror, box of towels and some alcohol. Clean and isolate.
     
    #4 frodoz737, Dec 19, 2014
  5. AzWxGuy

    AzWxGuy Weather Guy

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    Is that for cleaning, or perhaps medicinal purposes?
     
    #5 AzWxGuy, Dec 19, 2014
    irrational likes this.
  6. RRxing

    RRxing Senior Member

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    Agreed. You stated that it started leaking after the engine warmed up, but did not mention specifically where the leak was coming from. Please give us an update...
     
    #6 RRxing, Dec 19, 2014
  7. irrational

    irrational Member

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    +1

    The oil is going somewhere. If all else fails, add some fluorescent dye to help locate it.
     
    #7 irrational, Dec 19, 2014
  8. frodoz737

    frodoz737 Top Wrench

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    #8 frodoz737, Dec 19, 2014
  9. Mendel Leisk

    Mendel Leisk Senior Member

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    Is it out of warranty?
     
    #9 Mendel Leisk, Dec 19, 2014
  10. KeinoDoggy

    KeinoDoggy Member

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    Could it be a leaking oil pressure sending unit?
     
    #10 KeinoDoggy, Dec 19, 2014
  11. SageBrush

    SageBrush Senior Member

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    New filter and O-ring
     
    #11 SageBrush, Dec 19, 2014
  12. css28

    css28 Senior Member

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    For what it's worth the oil pressure is probably highest when firs tstarted cold.

    As others have suggested, you need to see where the leak is.
     
    #12 css28, Dec 19, 2014
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