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Baby's First Engine Knock

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by bclikesyou, Jan 18, 2022.

  1. bclikesyou

    bclikesyou Junior Member

    Joined:
    Jan 18, 2022
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    Location:
    Rochester, NY
    Vehicle:
    2015 Prius c
    Model:
    Two
    2015 Prius C Two
    36k miles
    I reside in WNY

    My car sat for a few days in our garage. Last I drove it was a short trip (2-3 miles) and I *think* I turned it off while the ICE was still running.

    Start it up today after a huge snowstorm and temp drop and I got the dreaded engine knocking for 5-7 seconds.

    I've read a bunch of threads and am trying to determine the next best steps:
    • I'll watch coolant levels
    • Wait until ICE stops to turn off the car
    • Could I actually have a head gasket failure at 36k?
    ✌
     
    #1 bclikesyou, Jan 18, 2022
  2. PriusCamper

    PriusCamper Senior Member

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    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    All Prius by nature run rough after not being started up for a while, especially in inclement weather. It's the nature of the Atkinson Engine... Nothing to be concerned about unless it gets way worse.
     
    #2 PriusCamper, Jan 19, 2022
    mikey_t likes this.
  3. privilege

    privilege Active Member

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    Vehicle:
    2011 Prius
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    1 this will cause all kinds of rattling on next start, consistently

    2 yup, but it's it the engine knocking, or the planetary , +trans just raising hell ?

    3 check oil, coolant, brake, etc levels at every fuel stop .. this is always a good idea

    4 very good practice

    5 highly unlikely, but possible of course.
     
    #3 privilege, Jan 19, 2022
  4. dig4dirt

    dig4dirt MoonGlow

    Joined:
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    Location:
    Lancaster Co PA
    Vehicle:
    2014 Prius c
    Model:
    Two
    You should be ok.

    Honestly I cannot remember my C ever starting with the knock,
    but in my Gen3 after the shutoff while running it knocked while restarting I think twice.
    As far as I can remember, it was like first or second year of owning it new, and after learning that (shutoff w/running)
    never happened for the next 4-5 years of owning it.

    I did have some funny acting in my C while really cold out 4-5 years ago, but
    since then I added an engine block heater and no such thing nowadays.
    2014c with 55k miles
     
    #4 dig4dirt, Jan 19, 2022
  5. rjdriver

    rjdriver Active Member

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    Location:
    Rhode Island
    Vehicle:
    2012 Prius c
    Model:
    Three
    How did I drive 150000 miles in my C with frequent (daily for quite a while) visits to this forum and this is the first time I have seen it recommended to not turn the car off with the ICE running? Just a guess, but I suspect that 70% of time I have turned the car off with the engine still running. Never had a knock or any other engine issues.

    What's the theory behind this recommendation?
     
    #5 rjdriver, Jan 19, 2022
  6. bclikesyou

    bclikesyou Junior Member

    Joined:
    Jan 18, 2022
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    Location:
    Rochester, NY
    Vehicle:
    2015 Prius c
    Model:
    Two
    Thanks for the replies everyone! I'll check back in another week or so with an update.
     
    #6 bclikesyou, Jan 19, 2022
    Mendel Leisk likes this.
  7. bclikesyou

    bclikesyou Junior Member

    Joined:
    Jan 18, 2022
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    Location:
    Rochester, NY
    Vehicle:
    2015 Prius c
    Model:
    Two
    I can't remember the exact reasoning but I found a handful of threads that recommended it while searching about the engine knocking. People mentioned head gasket failure, spark plug replacement, fuel injector cleaning, and condensation on the intake manifold(?). I could be wrong but I think condensation on the intake manifold was more likely if you turned the car off while the ICE was running. Again - I'm drawing from memory here.

    Sounds like you've lucked out with no engine knock!
     
    #7 bclikesyou, Jan 20, 2022
  8. bclikesyou

    bclikesyou Junior Member

    Joined:
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    Location:
    Rochester, NY
    Vehicle:
    2015 Prius c
    Model:
    Two
    Quick update: Car sat in our garage for ~36 hours. ICE wasn't running when I turned it off. Started up this morning (13℉) and had no knock! I discussed this all with my wife and we figured that the car had sat for 5 days (previous to the knocking) without running and also while the temps dropped from 35-40℉ to close to 0℉ and during a snowstorm.

    I'll occasionally update this thread for posterity and in the event something pops up. We have a run of below-freezing days coming up here in WNY and I occasionally work from home, so the car could sit for a day or two.

    Thanks again for the help! I'm not a big car guy but damn I love this 'lil hatchback and now I get it!
     
    #8 bclikesyou, Jan 20, 2022
    rjdriver and dig4dirt like this.
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