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Faint rumbling sound while accelerating

Discussion in 'Prius c Technical Discussion' started by Mycatrico, Jan 28, 2022.

  1. Mycatrico

    Mycatrico New Member

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    Manchester, NH
    Vehicle:
    2015 Prius c
    Model:
    One
    I just purchased a used 2015 Prius C 104k miles and whenever I accelerate, I hear a faint rumbling sound from the engine. I hear it around 30-50mph. Could this be due to the cold New England weather? Also, I found it not as zippy as my 2013 Prius C in terms of acceleration. However, my 2013 never saw cold weather while it’s entire life was in Los Angeles. Could it possibly be a soon to be failed transaxle? I changed the cabin/engine filter and new oil. I’m getting the inverter/engine coolant, brake flush and transaxle fluid done. If the issue persists, could be it something more serious?
     
    #1 Mycatrico, Jan 28, 2022
  2. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Transaxle failure is pretty darn rare in these. Toyota does not have a replacement guideline for the fluid in there- they say it's good for life. I think they might be right, personally. If you do decide to have it changed, make certain they use genuine Toyota WS fluid; accept no substitute.

    Are you certain that the noise is from the engine? You might try changing the monitor screen to show you when the engine is actually running, that might help you eliminate noise sources.

    Mostly a wild guess, but perhaps check on the wheel bearings. They can be a major source of noise and you could have one or more worn out by 104k.

    Toyota changed very little between the 2013 and 2015 model years, so it might be tricky to nail down the performance difference. That said, someone could've accidentally installed the wrong tire size on one of these cars and that alone would make a difference.

    Check the battery cooling fan under the left rear seat. Make sure it isn't blocked or full of pet hair or dust. There are several youtube videos that show how to gain access and clean it with an ordinary vacuum cleaner.
     
    #2 Leadfoot J. McCoalroller, Jan 28, 2022
    Mycatrico and dig4dirt like this.
  3. Mycatrico

    Mycatrico New Member

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    thank you! I will have all this checked out at the shop.
     
    #3 Mycatrico, Jan 29, 2022
  4. Sonic_TH

    Sonic_TH Active Member

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    Location:
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    2012 Prius c
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    Any updates?
     
    #4 Sonic_TH, Jan 31, 2022
  5. Mycatrico

    Mycatrico New Member

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    One
    I had the brake fluid, inverter and engine coolant, oil change, both air filters, hybrid fan cleaned, spark plugs, and transaxle fluid all done. I no longer hear a any strange noises. It could have been the engine air filter as it was extremely dirty.
     
    #5 Mycatrico, Feb 4, 2022
  6. tankyuong

    tankyuong Senior Member

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    I have shudder at low speeds but then I have 230k miles
     
    #6 tankyuong, Feb 14, 2022
  7. Sonic_TH

    Sonic_TH Active Member

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    If i'm right, as far as i know, there has been no reported cases of transaxle failure on the Toyota Prius C.
     
    #7 Sonic_TH, Feb 14, 2022
  8. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Just keep it in perspective: Toyota has produced about 1.5 million Aqua/Prius c cars, but there are only a few thousand owners signed up on priuschat and far fewer are active today.

    So in the grand scheme of things, our sample size is too small to matter.
     
    #8 Leadfoot J. McCoalroller, Feb 15, 2022
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