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noise from hybrid system

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Groger, Nov 30, 2016.

  1. Groger

    Groger Member

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    Hi

    As per subject, 2011 Gen 3, after first winter storm of the year, car was outside. I drove 5 feet to get the snow out and noticed this high schreech noise coming from Hybrid system. turned off the car, later that morning, drove in to work, on the way in, the high schreech would come back, didn't mater if I was driving, stopped or anything. But when the engine was warmed up, I didn't hear anything anymore. Temp was 32F (0C).

    Any ideas? This car is new to me, only had it for 1.5 months now. First time I hear this, but also first snow storm as well.

    Thanks
     
    #1 Groger, Nov 30, 2016
  2. fotomoto

    fotomoto Senior Member

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    It's coming from the brakes.

    Hybrids, if driven correctly, don't use the traditional fiction brakes (rotors, pads) very much and rely on the regeneration braking from the hybrid motors. So, the friction brakes don't get as hot as with other cars and can develop light rust on the rotors. Using them the again after a cool down period makes for squeaks, groans, etc. Moderate braking at the next stop should clean off the light rust enough to make them quite again.

    No worries.
     
    #2 fotomoto, Nov 30, 2016
  3. Groger

    Groger Member

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    That is what I thought I first as well, but it was happening also while I was driving. And it was on and off, made the sound, stopped, no wait here it is again and so forth. and it wasn't constant either. it sounded almost like you where scratching a record, pulling the needle across the record, kind off. After about 10 min of driving, it when away.
     
    #3 Groger, Nov 30, 2016
  4. fotomoto

    fotomoto Senior Member

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    Yup. Next time this happens, use the brakes fairly hard when it's safe to do so. If the issue still persists, then look elsewhere. My guess is because you're in snowy conditions, you're (wisely) still lightly braking and not getting the rotors/pads warm enough.
     
    #4 fotomoto, Nov 30, 2016
  5. jdcollins5

    jdcollins5 Senior Member

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    At one of your stops put it in neutral just prior to braking. This disables the regen braking and forces the friction brakes for the stopping. This will help wipe the rust off of the rotors and any sticking of the calipers.

    You may have to do this multiple times and pump the brakes.
     
    #5 jdcollins5, Nov 30, 2016
    fotomoto likes this.
  6. Groger

    Groger Member

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    I'm sure it also did it while the car was in park, but I will have to do more investigation.

    Thank you for your help.
     
    #6 Groger, Nov 30, 2016
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Just for giggles, look under the car, see if anything's hanging down. There's plastic panels, maybe something got dislodged by snow? One panel in particular at the engine bay is abused by mechanics during oil changes, commonly ends up hanging down.
     
    #7 Mendel Leisk, Nov 30, 2016
  8. Groger

    Groger Member

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    Thanks everyone for your responses, I will check.
     
    #8 Groger, Nov 30, 2016
    Mendel Leisk likes this.
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