Prius c engine noise after turning engine off

Discussion in 'Prius c Technical Discussion' started by Magikal, Jul 5, 2017.

  1. Magikal

    Magikal Junior Member

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    I just bought this used prius c 2015 42k miles yesterday. Please tell me this is some normal phenomenon. I can't find anything similar online. This is after a 10 mile drive and be car is completely off. Sounds like it's coming from the gas engine.

     
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  2. Magikal

    Magikal Junior Member

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    Just went out and checked again. Could it be the AC?
     
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  3. Sean Nelson

    Sean Nelson Active Member

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    I can't say exactly what it is, but it certainly doesn't sound like the engine. The Prius C has a number of electrically-driven systems that can come on when the car is turned off, which is perfectly normal.
     
  4. Magikal

    Magikal Junior Member

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    Thanks. I'm pretty sure it's fluids running from really cold a/c. This is when the engine is turned off btw
     
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  5. davids45

    davids45 Active Member

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    G'day,

    About 5-10 minutes after turning off my 'c', a "normal" sound from a delayed process (maybe from the HV battery system? It happens when the a-c had not been in use) is heard (if someone is still in or by the car - reminiscent of the philosophical 'argument' about a tree chopped down in a forest, does it make a noise if no one is there to hear it?).

    Conversely, I'm not sure if there is a problem if this sound (process) doesn't happen after turn-off?

    I think somewhere on PriusChat is a post with the cause of this delayed sound in a Prius (maybe not a 'c') but I don't know where it is.

    David S.
     
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  6. Magikal

    Magikal Junior Member

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    Yeah that's the coolant system I think. Mines the ac
     
  7. bisco

    bisco cookie crumbler

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    the a/c turns off with the car, so i'm not sure what it is. can you hear it without the hood open?
     
    #7 bisco, Jul 6, 2017
    Last edited: Jul 6, 2017
  8. Magikal

    Magikal Junior Member

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    Yep but just barely
     
  9. bisco

    bisco cookie crumbler

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    i'll try to listen with the hood closed, but i don't recall ever hearing anything but the brake accumulator.
     
  10. Sam Spade

    Sam Spade Senior Member

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    Yes but......the pressures equalize inside the system when it goes OFF......so some gurgling noises are quite normal.
    I think I've also heard the brake booster pump run immediately after shutting off sometimes.
     
  11. Phil Viana

    Phil Viana New Member

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    My Prius C makes the very same noise. I drove for 30 minutes with the AC off and I could NOT hear the noise once I turned my car off. Definitely AC related but I don't know what exactly. Let me know if you find out.
     
  12. Javierz0509

    Javierz0509 Member

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    Does it need freon?
     
  13. Phil Viana

    Phil Viana New Member

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    I took the car to my mechanic and he said the noise is perfectly normal. There is nothing to fix.

    It does not need freon AFAIK. It's cooling just fine.
     
  14. TheTimob

    TheTimob Member

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    There are several sounds that the car makes after being turned off. The Vacuum pump for the brakes is the loudest. That's the prius "moo". Mash the pedal a bunch while you're sitting at a light to make the car moo.

    The A/C gurgle - it happens on every car with A/C, but it is more noticeable on the Prius.

    The cooling system will also have some natural circulation with hot coolant flowing around to the cooler parts in the system. Other cars do this too. The EGR is water cooled, the inverter is water cooled, and there is also a head exchanger in the exhaust for the cabin heat. There's a lot of neat stuff going on. This is different from the Gen2 Prius- the Gen2 has an insulated thermos container in the bumper that it'll fill up with hot coolant with an electric pump to reduce warm-up time on the next start. Pretty neat, but I'm sure it adds complexity and cost that toyota was able to eliminate for the Gen3 and the C.

    EDIT: that sound in the video is the A/C for sure
     
  15. Skidz

    Skidz New Member

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    Hey guys....any update on this..my car is making the same sound....
     
  16. Skidz

    Skidz New Member

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    I drove the car witj ac...heard the noise...drove it without ac...didnt hear anything so im sure its really the ac causing it...so i wouldnt worry if u guys said that its pretty normal
     
  17. Sky_Velleity

    Sky_Velleity New Member

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    Mine's made this sound since it was brand new, it's just the engine settling down as it cools.
    Absolutely nothing to worry about, they can just be noisy like this. If anyone's too concerned, I'll do a couple tests to work out what's specifically causing it, I'd bet either coolant in the inverter or pressure in the AC system equalising.
     
  18. Oldwolf

    Oldwolf Prius Enthusiast

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    The A/C system has a high pressure side and low pressure side. When you turn the main power off with the A/C running, you will hear the two sides equalizing in pressure. If you turn the A/C off by pushing only the A/C button (which only turns on/off the compressor but leaves the A/C fan on) about 60 seconds before you park and shut off the main power, the pressures will have equalized and you will not hear the sound.
     
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  19. davidc83

    davidc83 Member

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    Read the owners manual. Many times it states the car makes all kinds of different noises after it is turned off as systems are shutting down...the car us basically a big computer on wheels...

    SM-S327VL ?
     
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