I am just wondering at what temp should I plug-in my truck. Being from South Texas I have no idea what a really cold temp is for the truck.

 

In South Texas you probably do not have to plug it in, but I generally do at any temperatures below freezing just to make it easier on the engine while warming up.

 

I am with dixie on this one,over use of the heater when not needed is costly,cause they do wear out!!!! Goodluck Rick

 

Thanks for the info

 

My friend told me that you only need to plug it in like 20 min. before you go anywhere because its not actually heating the oil or anything, just the pistons. Is he right or how does this work? Thanks

 

The block heater warms up the water in the block, to help keep the oil a little thinner, and help ease the load on the starter on those frigid mornings.
I plug mine in for 3 hours before starting in the mornings.
I think your friend is thinking of Glow Plugs (Cummins doesn't use 'em) that Chevys and Fords use to prewarm the combustion chambers.

 

It heats the water,which inturn heats the oil somewhat,and the rest of the engine where water goes,as far as the time goes 20 minutes isn't going to cut it,I would recommend at least 2 hrs before to do any good at all, I also recommend a GFI outlet and a good timer that will come on the 2 hrs before you would be using the truck, that time frame works well for me all the way down to 0 degrees which it does not get that here very often,I do not plug in unless it is going to get down to say below 32 some will say any time below 40 you will have to weigh that one out for your own,Now I have other gas vehicles to use at my discretion so if you do not and you might see a need for using your truck at anytime IE: emergencys and such leave it plugged in.Goodluck Rick

 

I leave my truck plugged in all day at work. If it's around 0*F the Wait-to-Start light doesn't even come on. At home in the garage I use a timer that turns on about 3 hrs before I leave. Plugging in makes a huge difference in the time it takes to get warm air out of the heater. This is a good thing way up here.

 

[quote author=berner link=board=5;threadid=22830;start=0#msg214386 date=1069857347]
If it's around 0*F
[/quote]

You're kidding, right? Zero degrees? As in 32 below the freezing point?

You are insane. Only manly men must live up in Canada. I'll hang out here with the wussies in Arizona! :P

 

[quote author=PHX_ATC link=board=5;threadid=22830;start=0#msg214413 date=1069860986]
[quote author=berner link=board=5;threadid=22830;start=0#msg214386 date=1069857347]
If it's around 0*F
[/quote]

You're kidding, right? Zero degrees? As in 32 below the freezing point?

You are insane. Only manly men must live up in Canada. I'll hang out here with the wussies in Arizona! :P
[/quote]

thats what im talking about! i hate cold weather.

 

[quote author=PHX_ATC link=board=5;threadid=22830;start=0#msg214413 date=1069860986]

You're kidding, right? Zero degrees? As in 32 below the freezing point?

You are insane. Only manly men must live up in Canada. I'll hang out here with the wussies in Arizona! :P
[/quote]
You haven't lived until you've changed a starter on the side of the road at -40* with a 20mph wind.

 

OK, I'm confused. How exactly does warm water in that big block of iron actually warm approx 10 qts of oil at in bottom of the oil pan? I know plugging in the engine will help get heat faster in the passenger compartment and keep the area around the pistons/head warm. Also, if the wait to start light is out when it's cold and plugged in then the PCM must determine outside temp from the water temp sender - sooo, does the fuel preheater still cycle to keep the fuel from gelling? Maybe I'm thinking too much into this (engineering mind).

 

I don't think it changes the oil temperature in the pan a bit. But when the circulating oil hits the warm block, I bet if flows better. Doesn't the PCM sense air temp, and not water temp to contol fuel and grid heaters? I know my grids cycle after starting even though the block has been plugged in.

 

The grid heaters in my '96 are controlled by the Air Temp Sensor in the back of the intake manifold. As far as oil temperature, when you plug in, it warms the coolant which in turn warms the block which in turn warms the oil. You'll find this out in a hurry when you start your truck in very cold weather without plugging it in. It'll turn over very slow, and take a lot longer to get the oil pressure up.

 

The block heater is not going to bring the engine up to running temps, but warm things up a little to make it easier on the starter and batteries to crank it over.