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Looking for winter driving tips

Discussion in 'Prius c Fuel Economy' started by Globalgirl13, Jan 11, 2016.

  1. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Yes the cabin heat comes from engine coolant. At a stop with the engine shut down, you can actually turn the engine on/off by setting cabin temp higher/lower. The lower you set cabin temperature, the more likely the engine is to shut down.
     
  2. rjdriver

    rjdriver Active Member

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    I don't think the block heater will result in much net savings in gas over the cost of the electricity to run it. But, for where you live, if your car is not garaged overnight and you plan to keep it for the long haul, it would certainly be worth the small investment just to increase the life of your engine. For anyone who changes their oil and filter religiously, and doesn't engage in frequent stop light drag races or other high revving activity, a good portion of the wear and tear on an internal combustion engine occurs in those few seconds it takes the oil to loosen up and circulate after a long cold night outdoors or sitting in a parking lot at work all day. Even the multi viscosity oils that we all use now do thicken up a little in the extreme cold. A block heater will both shorten warm up time and quicken oil circulation upon starting. Kill two birds.

    Your other issue is most certainly cabin temperature. As others have suggested, the lower you can stand the temperature in the car, the less frequently the engine will have to kick in to keep you warm. My average gas mileage to work drops from 60 MPG to about 55 in the winter, so none of this is unusual. The cabin heater also mentioned sounds like great way to be able to get into a nice warm car every morning. But that benefit goes away quickly after it's unplugged, and the C will ultimately need to keep you warm for most of the drive.

    Then again, those hills and stop lights are a mileage killer, so don't get your hopes too high. Drop back a few Mph on the way up the hills and coast as much as possible on the downsides. Trying to maintain a steady speed is not a good idea. Ultimately, it sounds like you just have one of those mileage robbing commutes. Good luck.
     
  3. Sean Nelson

    Sean Nelson Active Member

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    The cabin heater uses heat from the engine coolant loop, but the engine doesn't have to run all the time. Once the engine is heated up the engine block and the coolant stay warm enough to heat the cabin even when the engine turns off again. Since you can't run off the battery indefinitely the engine is going to come on sooner or later to provide motive power, and when it does it heats up the coolant again. So for the most part, once the engine has heated up, the cabin gets heated "for free".

    Of course the colder the temperatures the more heat you need, so at some point you may run out of heat in the coolant loop before you run out of battery (especially if you're going downhill), and then the engine would have to come on solely to heat the cabin. But it would probably recharge the battery at the same time, so for the most part it's still not "just" for the cabin heat.
     
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  4. priustexasbob

    priustexasbob Member

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    I'm a wuss, when it gets really cold, yanno 40°F, I run my heater all the time set the temp at 80.
     
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  5. SwhitePC

    SwhitePC Active Member

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    warm up your engine early, don't use heat

    do some grill blocking to keep your engine warm(er) during the drive
     
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  6. dborn

    dborn Junior Member

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    Hi Deb,
    Unfortunately (for you!) there is no pre-block heater days on this car... ;)
    She gets between 537 and 609km per tank and puts in between 27.2 and 30.2 liters of gas.

    Hope this helps,
    Daniel
     
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  7. Blizzard_Persona

    Blizzard_Persona Senior Member

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    This guy has winter driven down pat I'd say!!:cool:
     
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  8. dborn

    dborn Junior Member

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    :) You'd be really unhappy in Canada (in my car)... 40F is warm for us (at least this time of year).

    Personally, the colder it gets, the lower I keep the temps in the car and I turn the heater off when I'm stopped.
     
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  9. Sabby

    Sabby Active Member

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    You have it right. The cabin heat comes from the engine coolant. A fully heated engine might be 190 degrees. You can go a pretty long ways drawing down the coolant temp down from 190 down to about 110 degrees before the engine will kick back on purely for cabin heat.

    In the winter one advantage to blocking the radiator, beyond quicker warm ups, is that the engine holds the heat longer for cabin heat purposes.
     
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  10. InPriusLove

    InPriusLove Member

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    @davidc83: If the engine needs to rev to heat up the fluids then sure it has to run more but if you set the climate goal to a moderate temperature like 72 it won't need to work as hard as if you set it for 79 or 80. At a lower temperature the ICE can stop at reasonable rates and the heater would still heat from its residual. I get much better mileage with lower heat settings.
     
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  11. priustexasbob

    priustexasbob Member

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    stay toasty or better mileage, stay toasty or better mileage - tough decision. while I love getting great mileage, I really hate being cold so I run my heater at 80. for clarity cool is anything under 60°F, cold under 50°f and very cold under 40°F. LOL

    oh, I live in southeast Texas. I am a wuss, but I am a warm wuss.
     
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  12. minkus

    minkus Active Member

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    I also wish that option existed: "Share some of the heat you have if it's x degrees above cabin temperature, but don't turn the ICE on just for me."
     
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  13. InPriusLove

    InPriusLove Member

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    It sort of does, by considering how hot the ICE actually becomes while running. The radiator of course overheats when the boiling point is reached which is why we must have coolant, to raise the boiling point. Run the ICE as usual and it will not start just for the heater. The two most important factors I consider are that gas consumption is highest at startup, and that at startup the heat has not yet generated. Starting the heater at startup may increase fuel consumption, so waiting a few blocks would enable more efficiency. Then driving at speeds that call for the ICE there is plenty heat to spare. Some people use various types of heaters but one to consider is a preheated pad for your lap, that you bring from the home. I have lived in cold climates comparatively when even non-hybrids have the same issue.
     
  14. dborn

    dborn Junior Member

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    I used to do that when I owned a Civic hybrid and I think it helped alot. However, I don't dare do this with my TCH or my wife's C as I'm afraid to cause overheating either to the ICE or the electrical system. I work really hard to get good gas mileage but I'm not willing to risk damaging the car for a few pennies saved. The HSD system is way more complex than on the Honda and probably requires proper cooling of components even in cold weather. If some want to do it, go ahead but don't over do it.
     
  15. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    A few precautions that'll help:

    1. Figure out where the transaxle radiator is, and avoid blocking that area.

    2. Without a way of monitoring coolant temps, keep it to 50% or less blocked.

    3. Once ambient temps are high enough that you've started rolling the windows down and/or using AC for cooling, cease grill blocking.
     
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  16. DKTVAV

    DKTVAV Active Member

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    So where's it?

    I have no idea where it is when looking from the front top/bottom left or top/bottom right of the radiator. I just block the whole bottom grill with the top grill open all year long. Using scan gauge II and checking the temp when outside above 100 the engine temp at the highest I've seen is about 202 degrees. Normally it's around 196 degrees. I remove them only before a car wash. It seems OK for almost four years now.
     
  17. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Sounds good.
     
  18. I'mJp

    I'mJp Senior Member

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    Work with the car.
    You engine generally will turn on going up hills, and when you speed up to cruising speed.
    Set your heat for 80 degrees and fan on max, then shut it off.
    When climbing a hill and engine turns on, turn heat-fan on max. At the top of the hill turn it off.
    Do same for accelerating.
    Wear a coat.
    Use the electric seats.
    jp