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Is it bad to turn off the engine while it's warming up?

Discussion in 'Generation 1 Prius Discussion' started by BentSpace, Jun 1, 2011.

  1. BentSpace

    BentSpace Member

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    When I'm leaving the house and I pull out onto the street, I have to go close up a very annoying gate which takes a good few minutes to do. The car is still in it's warm up mode so the ICE is running the whole time. I know just turning it off would save gas, but would it be bad for the engine, to turn it off with the key before it shuts itself off?
     
    #1 BentSpace, Jun 1, 2011
  2. Troyroy

    Troyroy Member

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    For the few minutes your talking about.....I would just leave it run...your not saving that much gas by shutting it down, then restarting it.

    As for the gate......get a electric gate closer.....make your life better.
     
    #2 Troyroy, Jun 2, 2011
  3. Rstaton

    Rstaton New Member

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    I think this would effectively warm up the engine more slowly, which is probably better because of reduced thermal shock. I've found that for short trips, there is a huge difference in MPG between letting the engine warm up first vs. just taking off immediately.
     
    #3 Rstaton, Jun 2, 2011
  4. BentSpace

    BentSpace Member

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    Yes, I dream of electric gates.:)
     
    #4 BentSpace, Jun 2, 2011
  5. BentSpace

    BentSpace Member

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    Are you saying less shock by turning it off then back on?

    So which way are you suggesting is better?
     
    #5 BentSpace, Jun 2, 2011
  6. darelldd

    darelldd Prius is our Gas Guzzler

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    Leave it run. For best mileage, you want the engine to get to operating temp before you do any sort of real driving. In fact, I've found the best approach is to just leave the car parked while it goes through the ICE warm up. THEN start driving. Definitely let it run is my advice.

    And then shop for an EV as your next car since you seem like a good candidate. ;)
     
    #6 darelldd, Jun 2, 2011
  7. Rstaton

    Rstaton New Member

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    Yes, that's what I'm saying. When it's first warming up, not all parts of the engine are the same temperature. If you let it run a little, then shut off for a few minutes, it gives more time for the initial heat to soak in.

    But I don't design car engines.

    The issue of whether to let it fully warm up may partially hinge on how cold the weather is. In cold weather, I would definitely say just let it warm up. But for California weather, warming up isn't as critical since it's already half way there to start with.
     
    #7 Rstaton, Jun 2, 2011
  8. BentSpace

    BentSpace Member

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    I thought I read somewhere awhile ago not to turn off any car while it's warming up because it will leave deposits in the engine or something like that due to it being cold and not reaching complete combustion.

    Is this true?

    Is it true with the Prius?
     
    #8 BentSpace, Jun 3, 2011
  9. gippah

    gippah New Member

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    I'm sure the engine could handle it. But why stress the battery? You are far more likely to go through more than one battery during the lifetime of the car than you are an engine.
     
    #9 gippah, Jun 4, 2011
  10. bisco

    bisco cookie crumbler

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    i think i read that too.
     
    #10 bisco, Jun 4, 2011
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