Block heater operation

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oilboy123

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My Dad has a Canadian Dodge Caravan. He lives North of Seattle and we are having a cold snap. It has a core plug block heater that draws around 565 watts. I set it to come on about 4 hours before he was to use the van. The overnight low was around 15 F. No wind to speak of.
When he started it in the morning the heat was not even warm. Is this normal. The air blowing was not freezing cold, but I expected a little warmth?

Is this normal sounding for a block heater? Should it be on all night, maybe 8 hrs minimum? I have never used one before.
 
Experienced the same thing in all my cars equipped with block heaters (including a 99 Dodge Caravan, if that helps you). The block heater is not making the coolant 180 degress like operating temperature, but heating it from ambient to somewhat above ambient.

I used a Scangauge II on my Subaru Outback H6 last winter and definitely the coolant was warmer (from memory around 38 without the block heater to 60ish with the block heater) from one day to the next with overnight ambient about the same on the two days I tested it.
 
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4 hours is plenty of time. Mine is in the timer for 2 hours before I need to start the car. Block heater will help with cold start-ups and will bring the engine to operating temperatures faster, but it will never bring coolant to 180F.

Try to start the truck without block heater on and turn the blower on. It will take extra 15-20 minutes for the cabin to warm up.
 
I'm going to try leaving it on all night and see how it does. I was not expecting it to heat to operating temps. I thought maybe it would at least go to over 100 F.
 
15F is not worth using a block heater at all given hassle.

It is much easier to go out and let the car idle for 5-10 mins and enjoy blowing heat/defrost instead of unplugging etc.
 
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Originally Posted By: oilboy123
My Dad has a Canadian Dodge Caravan. He lives North of Seattle and we are having a cold snap. It has a core plug block heater that draws around 565 watts. I set it to come on about 4 hours before he was to use the van. The overnight low was around 15 F. No wind to speak of.
When he started it in the morning the heat was not even warm. Is this normal. The air blowing was not freezing cold, but I expected a little warmth?

Is this normal sounding for a block heater? Should it be on all night, maybe 8 hrs minimum? I have never used one before.


I have one in my E-150 factory installed. It does little to nothing as far as I can tell. I have better luck with the oil pan heater I installed on the Jeep. YMMV
 
565watts to heat the engine, oil, and coolant when its 15F outside. That is a lot of items that act as heatsink. The block heater was never intended to heat all those items as well as the coolant so that it is going to blow warm air when you crank it over. Its meant to ease starting and get you going quicker with less wear and tear. A normal electric kettle has near 1000W to heat up just 1/2 gallon of water, and that is inside your house with at least 70F ambient temperature. Put that kettle outside at 15F and see how long it takes.

I agree with Ursae_Majoris, try leaving it unplugged all night and compare the time until operating temps are reached.
 
Mine (800-1000W) will heat the coolant about 20F in the first hour, with dimishing returns after that. If I leave it on all night it will end up about 70F above ambient. Anything beyond a couple hours and most of the heat I'm buying goes into the garage air (or outside air).

It would be silly (and expensive) to try to use electric heat to warm 1000 lb of metal and fluids up to operating temps.
 
I wouldn't waste the electricity on a block heater for any running car when it is above zero. Any car, say less than 15 years old and in good running condition I wouldn't think about until -40. At least, that is what 25 years of living in MN taught me.

Clark
 
Originally Posted By: oilboy123
I'm going to try leaving it on all night and see how it does. I was not expecting it to heat to operating temps. I thought maybe it would at least go to over 100 F.


If you have a stable ambient, see what it reaches overnight. Then start backing off your timer to the point where it's lower. Then you can factor the costs differences.

btw-100F coolant in a heater core doesn't feel all that warm with many CFM of 15F air blowing through it. It has to be over your skin temp to feel warm to begin with.
 
I've never had warm air from the heater when using a block heater except with my previous car, an '87 Grand Am with an iron block and heads that was covered in a blanket of sludge from years of having a leaky valve cover gasket.

I don't think there's much benefit to plugging in for more than four hours, but you'll never know for sure for a particular vehicle unless you try it.
 
Four hours is all you need. It will allow your heater to get up to temp faster than not using the block heater, You can add another block heater if you want more heat and faster.
 
My Dad is pushing 80 years old. He takes my Niece to school in the morning. I was thinking more of his comfort level, he gets cold a lot easier than he used to.
 
You can also Buy heaters for inside the car. These would plug in with the block heater and come on when plugged in or with timer. Car is then toasty warm when you get in. I haven't seen them for a while, but expect they are still for sale. One of the small ceramic cube heaters would do the same.
 
Actually, most people do the same thing and try to minimize the amount of electricity they buy so they use timers. If its heat you want, then these s/b plugged in right after vehicle has been in operation and LEFT ON ALL NIGHT. The limited watts and lack of REAL circulation really won't provide heat in a zone (nite temps< 10º) that you think you might get. Yes, a timer will make easier to crank around zero but you're not goona feel any heat.
 
Having lived in ND most of my life, I have learned that having a block heater is a must. I have one in all 6 of my cars. I have also learned that you really don't need them until the temps fall below 0 F. Most hotels in the state provide electrical outlets in the parkin lots. Thus you shouls alway carry a extension cord when traveling.
 
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