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A strange situation with engine rattling

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Zabrodov, Oct 14, 2018.

  1. Zabrodov

    Zabrodov New Member

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    2011 Prius
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    Hi all,

    I have a bit of a situation here and I was wondering if anyone has ever encountered a similar thing.
    Three days ago I decided to check the engine oil level in my 3rd gen 2011 Prius and the dipstick barely had oil on it. No oil warning light on the dashboard. I bought 5qt of Mobil 1 0w20 oil and poured 2 qts in the engine while checking the oil level. 2 qts seemed enough as per the dipstick since it showed that the level of oil is close to max.
    I drove like 20 miles that day and everything was fine with the car.

    Then the car was parked for two days and today I decided to check the oil level again. Btw, I did both oil checks only when the engine was cold. So today the oil level was shown way beyond the maximum level on the dipstick. It was like twice the min-max distance.

    I decided that it would be safer and easier to just drive to a closest oil change place and change the oil, bringing it to the required level. When I started the car to drive to the oil change place, the engine started rattling and shacking. I turned it off, then turned it on again - same story. I thought "well, apparently my engine is fu***d". Then I tried to check the engine differently by starting the car and changing the gear from "parked" to something else and the miracle happened: the engine stopped rattling and was running smoothly. I repeated the test a couple of times and with each time with the "Parked" gear the engine was rattling less and less. Eventually, the rattling almost disappeared when in the "Parked" gear and was completely absent when the gear was in any other status.

    I drove to the oil change place. They did a "complete" vehicle check and didn't find any issues. They changed the oil and after that I was able to happily drive back home. Now, there is no rattling at all, even with the "Parked" gear. The engine behaves like nothing happened, which leaves me extremely confused on what to do.

    There is no rattling or shacking anymore, but something did happen and caused the engine to work abnormally. And I have no idea what was going on and what should I do now.

    I forgot to mention that the car mileage is 135,000 miles and that throughout the whole story there were no warning lights on the dashboard.
     
    #1 Zabrodov, Oct 14, 2018
  2. bisco

    bisco cookie crumbler

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    welcome!

    search for threads regarding the egr circuit, intake manifold, oil catch can and failed head gasket.
    gen 3 has known problems in these area, and some research might help you understand them better.

    look specifically for threads from members danlatu and nutzaboutbolts. all the best!(y)
     
    #2 bisco, Oct 14, 2018
  3. fuzzy1

    fuzzy1 Senior Member

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    Like all vehicles I've ever owned or operated, Prius does not have any warning light for low oil level. Its oil light is only for low oil pressure.
     
    #3 fuzzy1, Oct 14, 2018
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Vehicle:
    2010 Prius
    Model:
    Touring
    My take is that you mis-read the level, the first time you checked the dipstick. Somehow???

    For a clearer picture when checking the dipstick: remove it, wipe it, and wait at least 5 minutes before reinserting for the check. The dipstick seem to draw oil up the tube when withdrawn, and makes it very difficult to read the level if your reinsert immediately.

    That does tend to make for a reading higher than actual though, so not explaining your situation. Anyway...

    I would just carry on, monitor the dipstick regularly.

    And I'd second @bisco's suggestions about "egr circuit, intake manifold, oil catch can and failed head gasket".
     
    #4 Mendel Leisk, Oct 15, 2018
    tankyuong likes this.
  5. Grit

    Grit Senior Member

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    Foaming probably occurred after you overfilled it and caused the start up knock. You should be checking engine oil level on a weekly basis with that many miles. Oil light will only light up when oil pressure is low, not low oil level. Good thing the oil light didn't light up, if it did irreversible damage to the engine is in process.
     
    #5 Grit, Oct 15, 2018
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