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Snow = no heat?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by stemchick, Dec 28, 2008.

  1. stemchick

    stemchick Montana Rocks!

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    We got a decent snow lately (about a foot), and sub zero temps. My 2008 Prius had no problems starting, but one morning after it had sat for a day, we went to start it, and there was NO heat. The next day we set it out in the sun (it actually made it above zero that day), and it warmed up, and we got heat again. Since then we have been starting it daily and have had no problems.

    My question for the forum is: Is it possible that snow got down in the vents by the winsheild and froze up the heater? I may sound blonde there, but the snow was packed pretty good by the wipers, and we dusted it off everywhere else, but didn't dig it out of there. I can't figure out what else may have caused the problem.

    And in case you were wondering, we are considering a garage or carport before next winter.
     
  2. efusco

    efusco Moderator Emeritus
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    Most likely the engine just never got warm enough to fully overcome the extreme cold. Believe it or not it's actually best to leave the heat turned to "max cold" (with A/C off and Auto off) for the initial part of the drive to allow the engine to warm up faster--if you can make it 2 miles before turning it on that'll help a lot.

    Consider an Engine block heater if you can plug in...even if the car stays outside...and yes, garaging will be better if you can manage it.
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The snow accumulation will prevent entry of outside air. However it will not prevent the cabin heater from operating.

    Note that the cabin heater system consists of the traditional heater core that obtains hot coolant from the engine, and two small electric heating elements. Until the engine has a chance to heat up, the amount of heated cabin air produced will be low since the electric heating elements produce the same heat as ~20% of a decent hairdryer.
     
  4. donee

    donee New Member

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    Hi Stemchick,

    In the winter your probably not running recirculate, as the windows would fog up. So, snow blockage between the windshield wipers and the hood on the passnerger side can be a problem. That is where the cabin ventilation intake vents are. You need to keep those clear for winter driving. If no air flows into that vent, no air flows across the heater core, and no heated air flows into the cabin. The aerodynamic design and location of the cabin air vents is such, that air pressure will not clear the vents, even at high speeds. The cabin air vent needs to be cleaned prior to driving. Once the snow is off the area use the brush in a hammer stroke to push any snow or ice stuck in the grill through.

    I do not think there is a problem with the enough snow getting through the vent, and collecting in an area that is not heated. As the slots in the intake air vent are backed up by a black wire mesh, with only about 2 mm square openings. Of course if the snow collected by the heater core, it would jut be melted. I think the problem is more related to my comments in the first paragraph.

    One alternative is to run with the windows cracked, and recirculate, if its sunny, and you have 1 or 2 people with dry clothes in the car. That way the humidity is ventilated, and air will flow over the heater core from inside the car and back. But typically one does not have a problem in sunny weather clearing the intake vent.

    Also, check to see if your cabin air filter is clean. Its amazing how dirty these get. The cabin air filter is behind the lower glove box. There are instructions how to tilt the glove box all the way down to get to the filter in the car manual, I believe.

    In weather below freezing allot of experienced Prius drivers will grill block. Being in Montana, I imagine you are familiar with this term. If you are doing local driving, on mostly cleared roads with limited highway miles, a full grill block is usually OK below 5 F.Below 32 F, a half grill block is OK for such driving. Without add-on instrumentation mountain driving, or continuous at-speed deep snow driving, or high speed continous highway driving might be a problem with a grill block.

    We use polyethylene foam tubing from the hardware store, that is sold to insulate water pipes. Split it apart lengthwise and stick one edge in one grill slot, and the other edge in a slot further down. You may need to slit the tubing crosswise so it will fit around the vertical recessed grill slats. 3/4 inch diameter will bridge two horizontal slats (blocking three grill slots). 1/2 inch diameter will bridge one slat, and block two grill slots.
     
  5. john1701a

    john1701a Prius Guru

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    Don't expect much heat from engine warm up. NO almost certainly wasn't the case. It was likely just a minimum from the sub-zero temps.

    With an aftermarket device, like ScanGauge, you can watch the temp of the engine coolant rise. That confirms all is well even before you can feel anything significant coming from the vents.
    .
     
  6. stemchick

    stemchick Montana Rocks!

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    okay...just to clarify....it wasn't like we turned the car on went "oh no heat" and turned it off. It was left to run in the sun for at least an hour. Still nothing happened. I do have to mention that it was 10 to 15 BELOW. This makes riding with the windows down a no go, as frostbite is a real concern at these temps.
     
  7. donee

    donee New Member

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    Hi Stemchick,

    Was the engine running continously during this stationary period?
     
  8. donee

    donee New Member

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    Hi Stemchick,

    I am familiar with such temperatures. I spent time in Northern Michigan, on the Keeweenaw Peninsula during my child hood. Where it was common for me to walk to and from school 4 miles in 0 degree F weather. Christmas day I was out for a nice hour and a half walk in 4 F weather. During college there was a 20 below day, and of course they canceled school as people in Central Illinois are not prepared for such cold. So, I just dressed up warm and walked the 5 miles off to the Ham Radio club. I was the only guy there, so I had sole usage of the equipment. It was great. I can still remember the guys in my dorm giving me serious advice not to go, as they were convinced I would be found in a snow bank frozen to death. :)

    I have also been out driving in 26 below weather, with 30 mph winds that happened some years ago here in Chicagoland.

    There are a few Prius drivers up north of you there in Alberta and Manitoba. They can fill you in on grill blocking they use on all their cars, not just Prius. -10 to -15 F is common there in the winter.
     
  9. john1701a

    john1701a Prius Guru

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    Just sitting there stationary won't produce much heat.

    It was -4°F on my commute home the other day. After 9 hours of leaving my Prius parked outside in the lot, I was getting decent heat at the 10-minute mark and was feeling pretty darn comfortable by the 15. There was no warm-up. I just pushed the button, fastened my seat-belt, then drove away seconds later.
    .
     
  10. efusco

    efusco Moderator Emeritus
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    Why would you do such a thing? What a waste of energy. The ICE will probably not even reach 100F under conditions like that It'll idle for a little while, shut down, sit there and get cold...when the battery gets low it'll come back on, idle and slightly warm the engine, then shut off and get cold.

    If you want it to get warm...drive it.
     
  11. usbseawolf2000

    usbseawolf2000 HSD PhD

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    I guess, this is a tip from my experience. After installing Wheelskin leather perforated cover, I can drive without the gloves on in the cold. It is one of those side benefits that you don't know until you have it.
     
  12. stemchick

    stemchick Montana Rocks!

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    okay...apparently no one else has had a problem with the snow getting down in the vents. That was what I was asking. I appreciate the responses, but I am not going to get in a car and drive down the road in below zero tempreatures when I am not sure my heat is going to work. My hubby says it was not even blowing as it normally does. It was like the fan was frozen up, and he says he found snow somewhere (near the heater?) that it wasn't supposed to be. The Toyota dealership in Billings said they had several problems reported like that in the recent snow.
     
  13. efusco

    efusco Moderator Emeritus
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    It won't blow much until the engine is warm...otherwise it will just be blowing cold air on you.
    Trust me, get in the car and drive it down the road, when the ICE gets warm it'll blow. If you're bundled up and can leave the heat set to max cold, AC-off, Auto-off for the first 5-10 minutes before turning the heat on you'll be able to get decent heat. If it sits in the driveway it'll never warm up, never blow and you'll still be cold...and it'll take LONGER for the car to warm up ultimately.

    IMO it has nothing at all to do with the snow getting in the vents.

    Also, if you're concerned about whether the fan will work or not just turn off the AUTO setting and manually set the fan speed where you like to prove to yourself it works. They designers made the car so that on auto it will operate as efficiently as possible given the various parameters...and that means not blowing if the blown air will be cold when you want heat.
     
  14. EZW1

    EZW1 Active Member

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    Stemchick, did you set the command temp all the way up to max? I think when you do that the Prius kicks in the electric heaters to supplement engine heat. Also, force it to recirc mode until the window fogs up, then hit the defog button until the window is clear, then turn it back off and it goes back into recirc mode. This may help you.

    I did this trick when I went north up to Flagstaff where the elevation was 7500ft and the morining temp was +3F. Setting the command temp to max gave me a little bit of heat until the engine warmed a bit.
     
  15. patsparks

    patsparks An Aussie perspective

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    Will defrost work in recirculate mode? I don't think it will, I think it automatically switches to fresh air.

    I agree with Evan, to get it warm you need to drive it. Go around the block if you don't trust it the first time and park it if the heat doesn't work in 5 mins. If it does you know tomorrow all you need to do is drive it.

    Is there a de-icing spray you can use? (I admit I know little of this problem)
     
  16. donee

    donee New Member

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    Hi Stemchick,

    Evan is right. It wont blow hard till the engine is warm. Until then it will blow softly, and use the electric heaters judiously (primarily for window defrosting). Did you know the car has two small electric heaters? When you smell the hot electrical smell, that is the electric heaters being used, but when the passenger air vent is blocked.

    Heat flows from a higher temperature to the lower. When the temperature difference is greater, heat flows faster. Heaters and Air Conditioners just setup the circumstances where the temperature difference is maximised.

    The Prius having a computer to figure this out does not turn on the fan until the temperature of the air available from the heater core is warm enough for efficient heat transfer. This creates the circumstances where the temperature difference is large, faster. Because it keeps heat in the engine. I am sure you do not run the fan high when its -15 F out, when you first get in the car, right? The Prius climate control is just doing this automatically.

    In some other threads, I came to the conclusion for really cold weather it would be nice if there was a gasoline powered furnace in the car. This way, the car would get warmed up efficiently. Most of the engine waste heat goes out the tailpipe. And with the smaller engine the water jacket waste heat is too small a fraction of the overall waste heat. SO in idling the car you only get about 20 % of the energy from the gas. And as there is not much gas being used while the car is idling, that is very little heat. If there was a furnace it would be 75 % efficient, and the exhaust from the furnace would be very clean.

    Some cold weather drivers have put an electric ceramic heater into the car to warm up the interior prior to driving. You want to be careful the heater is supported properly, does not blow directly on flamable materials, and cannot fall down unattended.
     
  17. qbee42

    qbee42 My other car is a boat

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    When you live in a state who's name means "wind", you may find you have more trouble with drifting snow than some others. It's fairly windy and snowy where we live, but we keep our Prius in the garage, so I can't say I've had the same trouble. I have had it happen with other cars when we kept them outside.

    Tom
     
  18. jayman

    jayman Senior Member

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    Been there, done that, didn't like it, decades ago back when I had to park outside. One thing we used to do up here, and some still do, if the car has to be left outside:

    Take a tarp, about 3-4 ft wide and 6-10 ft long. Open the front driver and passenger doors. Unroll the tarp so it covers the windshield and cowl area, drape it over so it goes inside the car. Slam the doors shut

    That way, the snow/frost/ice is kept off the windshield and cowl area where the HVAC sucks in its air. It looks ugly as hell to have this tarp draped over your windshield, but it WORKS

    Or, you do what I do: have a well insulated attached garage, with a Reznor 35,000 BTU natural gas heater that is CSA certified for residential garage use. I'm getting too old and too miserable (Ask any of the forum members, they'll agree with that self-assessment) to deal with icy windshields and clogged heater ducts
     
  19. jayman

    jayman Senior Member

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    You mean like this one?

    BlueHeat® Main

    Apparently, they are popular in Scandinavian countries, and they really do make sense. Especially if you can't plug in. For a diesel engine, they are probably mandatory, as it's difficult to cold-start a diesel engine in winter

    The heavy trucking industry has widespread use of engine and cab heaters to eliminate engine idle time, which uses a lot of fuel and is hard on a diesel engine. There are myths that idling is GOOD for a diesel engine: bulls***, it's bad for the motor

    The European Espar is popular for large trucks

    Espar - HYDRONIC 10

    The Teleflex ProHeat is another popular heavy truck coolant/cab heater

    Teleflex Power Systems - Idle Reduction & Power Management Solutions

    Going one step further, Teleflex/Carrier make a diesel powered APU for heavy duty trucks.

    http://www.trucktrailer.carrier.com/Files/TruckTrailer/Local/US-en/trucktrailer/comfortpro.pdf

    This keeps the engine and cab warm in winter, and the batteries fully charged (Very important in arctic temps!). In summer, the APU can run the A/C without idling the big motor, for substantial fuel savings

    I would never do that. Although tempting, and it *would* work, it also seems every cold snap, there is a rash of car fires here when the electric heater manages to set the damn car on fire
     
  20. patsparks

    patsparks An Aussie perspective

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    I agree with jayman, he is a grumpy old fart!

    If you want an electric heater in the car how would an oil filled convection heater go?