I plug mine in when it gets around 20F, if you leave the heater control set in defrost your windshield will be half defrosted in the morning

 

Years ago in JCWhitney catalog, they had a short extension cord (about 3') that had a thermostatic switch. You plug it in between your normal extension cord and the vehicle but it wouldn't flow electricity until it got down to about 35 degrees. Not sure if they still make one or not.

 

Not trying to hijack but when you guys plug yours in do you hear a hiss? Mine does. Is this normal?

 

mine doesnt hiss and i havent heard one that does


but that doesnt mean that its not normal, so hold tight until a block heater expert comes around

 

I read that and the first image that ran through my head was a brand new F-350 that caught fire and burned to the ground down the street from me because the block heater cord shorted to the bumper or something. $52,000 down the drain.

No, your truck should NOT hiss when you plug it in.

 

I didn't think that it should. My 94 didn't and I didn't know if something changed on the 01? I'll have to dig around in there and see if I can find something wrong.

 

couple points
Living up here in Norther Labrador (in Canada) I know ALLLLL about cold starts. but the how long it takes to heat up will also depend on the wind chil factor. That is how quickly the wind will remove heat from something. So it "feels" colder then it actualy is. Like this morning its about -30 celcius but a windchill factor of -45. It feels colder becuase the wind is taking the heat away from anything warm. Now its only about to bring the temperature of anything down to -30 (todays temp) but it will do it much faster. So how long you leave your block heater pluged in one day may be diffrent then another depending on the wind. Also always try to park a plugged in vehicle in an area sheltered from the wind.

Now about the Hissing sound, every vehicle i have ever owned i have been plugging in from mid november to start of april and i have always heard a hiss sound. Dont know what causes it but I dont worry about it. Just make sure you keep your electrical cords in good condition, i would even recomend you use loom near sharp edges. Also watch long run with extention cords, the longer the extention cord, the bigger the voltage drop and a higher probability of fire. and if you are going to have a long cord, make sure you get a bigger guage wire in it.

Just my opinions
Cold Man

 

Yes, it's normal. Should sound just like the water heater in your house when it is heating.

 

I plug my truck in when temps are zero or below. Or, if im up north and i have not driven my truck in a few days, ill plug it in a few hours before i leave. With my GP system working well, last year, it was -5 and i forgot to plug it in, the next morning it still started ok. Smoked like a frieght train, but then 15 miles down the road i got shut down due to gelled fuel in the tank, go figure.

 

Yes the hissing noise is normal, its when the coil first heats up and hits the cold antifreeze, anything with a block heater does it.

 

What we need is someone (ahem, ernesteugene) with the desire, knowledge, and time to figure out if there is a cost benefit to plugging in your block heater in even moderately cold weather. For instance, maybe when it is 30 degrees you get less mpg during the period while the engine is warming up, and that would easily offset the $1 a day in electricity.

Then of course there is wear. Cold oil not circulating well immediately, during the critical few minutes that the engine is warming up. That alone is justification in my mind to plug the thing in when it is 40 or below. But of course it would be hard to prove. Maybe my motor makes 400k miles because I do that, whereas it would only make 300k if I didn't? How would you ever know for sure?

Another thing; Since the heater heats the coolant, it probably would not be too hard to rig up a closed-loop system with a thermostat or sensor and a relay or solid-state switch, so that the block heater comes on only when it needs to, and for only as long as it needs to. For instance, plugging in your block heater when you first get home, with a hot engine, is a complete waste of a couple of kilowatt hours, as that heater is going to pull a kW even if the motor is hot. If you had a closed-loop controller, that wouldn't happen, and the heater would not run continuously all night, unless it was REALLY cold. So at 40 degrees out it might cycle on and off at a 50% duty cycle or something like that.

You could probably also add a small electric water pump, to slowly circulate the coolant through the motor and the heater core, to get more even heating. Maybe that's getting a little carried away.

I'll bet this has all been explored pretty well by people that design and work with fire trucks. They MUST keep those things warm all of the time. Talk about a hard llife, start it up and immediately WHOMP on it!!

Anyway, it would be a fun and interesting project. Wish I had the time. But for now, I think I will take the timer route.

 

The one emergency generator we have at work (a cummins with a 40kw genset) has that exact setup. The coolant is constantly circulated by a small pump/heater assembly. It keeps the outlet hot enough that you nearly burn yourself and lets the engine take the full load of the genset sooner. Even with that, its still recommended that you wait five minutes for the engine to warm up some before loading it down.

 

i plug mine in when it hits 30 or less, and usually i plug it in just before i go to bed.

 

well, I have been setting mine on a timer to warm for approx. 3 hours and am convinced it's just all around better. It seems to me the motor and electrical all work harder without it. JMO

 

i have not plugged my truck in once yet sins iv owned my truck back on September, 2006.