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EBH and ambient temperature

Discussion in 'Gen 2 Prius Fuel Economy' started by nerfer, Sep 21, 2014.

  1. nerfer

    nerfer A young senior member

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    I started collecting data on using the Engine Block Heater or not, to see what kind of difference it makes, and to see what the upper end of noticeable difference was. I was rather surprised to see that it continued to make a difference all the way into summer, in fact, more of a difference than in the dead of winter.

    At -10'F, the engine was cold enough and I needed heat for myself and the windows, so the engine ran pretty much all the time regardless, and there was no difference observed. At warmer temps I only ran the heat if the engine coolant temp was over 157'F or the windows needed defrosting. I figure I still have my coat on, and I'm out of the wind, why does the interior of the car need to be at indoor temps?

    I messed up the data collection early, I assumed my commute home was similar to my commute to work, so I was using that as my non-EBH values at first. Then I realized that going to work I started at 45 mph speeds, then worked down to 30-35 mph speeds when the engine was warm. Going back home, I started at lower speeds, but was above the 41 mph engine cut-off speed for most of the last part of the commute, so hyper-miling was harder. So I threw out much of my early no-EBH data. This winter I will try to rectify that.

    [​IMG]
    (I used a Scanguage II to collect trip mileage. Same path taken every time, similar conditions.)
     
    #1 nerfer, Sep 21, 2014
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    We use the block heater year 'round. In summer, if ambient temp is say 20C, the ScanGauge will be showing 40~45C, after around 2 hours plug-in. Within a block, with a bit of warm up and I'm sure some homogenizing of the fluid temps, it'll be up to 50C.

    We use it virtually without fail, for the first start up of the day. For one thing, it makes for a coddled engine. It also gets the car through the warm up zone much faster. Doubly important on short trips.

    Don't have the patience/smarts to quantify it as you have, nice to hear some confirmation.
     
    #2 Mendel Leisk, Sep 22, 2014
  3. Aaron Vitolins

    Aaron Vitolins Senior Member

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    how difficult is it to install a block heater in a Prius?
     
    #3 Aaron Vitolins, Sep 22, 2014
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Moderately tough, due to it being around back of engine block and near the bottom. The dealerships will do it for around $250 all-in, which you might want to consider. The part is available for $50~60 through the shop here, or through dealerships for around the same. It does not require coolant draining, which is good.

    We got ours installed by the dealership at time of purchase, for a ridiculously high amount. Toyota Canada now advertises installed price significantly lower (grrr).

    With our install they just coiled the plug-in cord and left it in the engine bay, leaving it for me to finish. I ran it out through the front grill, with the cord paralleling a grill slat, tightly secured with two zip ties, spaced a few inches apart.

    I plug it into an extension cord with a relatively easy pull out, anchored to something heavy directly in front of the car, so that if and when I forget to unplug it pulls straight out, and the block heater cord stays where it is on the grill, does not end up dragging down the road.

    Like the last time...
     
    #4 Mendel Leisk, Sep 22, 2014
    Last edited: Sep 22, 2014
    Aaron Vitolins likes this.
  5. Aaron Vitolins

    Aaron Vitolins Senior Member

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    Dang, I was hoping it would be easy! Do you have to remove any parts to install the heater or is it just a difficult location. Toyota should really install them as standard at least in the states that have cold winters. And of course standard in Canada!
     
    #5 Aaron Vitolins, Sep 22, 2014
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    With a second gen I'm not that familiar, I think there isn't a plastic shield under the engine bay? One less obstical. Personally (and I've never done an install) I'd opt to install from the underside, raise the front onto ramps or jack stands. From the top you're forced to remove the wipers, motors and cowl, I believe. Plus, the unit goes into a tube in what's pretty much a Braille process, you can reach it but hard to see. You put a heat-transfer lube on it, and even that is a little tricky. I believe it's a good trick to leave a little groove in the lube, so it can vent as you push it in.

    Just for warranty, I'm inclined to let the pros do it, lol. But there's a lot of people here who've diy'd this. Hopefully get some second gen chime in soon.

    And yeah, they should legislate factory install of these. Typically, the block heaters are immersed in coolant, and dealership install is a sad waste of coolant, and it's never the easiest time to do the install. OTOH, a lot of cars have block heaters installed, but they're not being used.
     
    #6 Mendel Leisk, Sep 22, 2014
  7. Scallywag

    Scallywag Member

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    There was a block heater fire a while back here... ahh, found it: Fire Sale | PriusChat
    So beware of the cord, I've seen other posts about issues.

    Also, I'd recommend the block heater on some sort of timer if possible/convenient. 350 watts is pretty cheap compared to the warm-up gas saved, but it's still wasted energy and probably pollution/money if it's always on.
     
    #7 Scallywag, Oct 2, 2014
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