plug in the engine block heater?

I have a block heater on my other truck, but it is a gas engine and unless the temp is forecast to go below 0 I do not bother. With the diesel I plugged it in last night as the temp was forecast to be near zero. It was 4. I was actually surprised that the SG2 showed a water temp of 110 when I did fire it up this morning. That is actually impressive on one hand, and makes me wonder what it is doing to my electric bill on the other.

So at what temp does it make sense to plug it in?

 

I believe they were advertised to start at -20* within 4 seconds IIRC. However, I usually plug mine in around 20-25 if I am driving it the next day. I like warmer start ups. Easier on the engine. Hadn't noticed any difference on electric bill. Of course, it doesn't get that cold that often here! While camping in mountains, I plug in into the campsite plug when below 25*

 

Plug in around 20f. Use a timer. Set it to come on 3 hours before start up

 

Don't bother unless it is actually below 0, even forgot a few times around -10 and it has started.

 

Yes! it will start unassisted easy in those temps. I have started mine as low as -1 with no problem at all.

but do remember what type of oil you are running. I run 15-40wt year around so that I why I plug in if it gets too cold.

Op is in Colorado so I would recommend switching to something that will take the colder temps better.

 

Good advice on the oil... 5W40 could be the ticket for those cold morning starts.

 

True I run 5w40 in the winter, actually need to change any day now.

 

Ambiet temp is 20 here this morning in Waco, TX and I just now got in the truck. I have the block heater and plugged it in last night so I would have a little heat. My Scangauge II says the WT is 84 degreees and the OT is 83 degrees. The heater has been on for 3 hours as I have a timer to come on at 3:30am. Even though I really do not need the block heater, it sure seems to make things start easier and I really like the heat to work when I get in.
(Sent from my Windows phone)

 

Ill plug in if its in the 30's, possibly low 40's. My 6.4 is my only vehicle and when I go to the gym at 5:30 in the morning, I don't want to run 5 miles with an ice cold engine to only let it sit for another hour then drive home to get ready for the day and let it sit again. I run a timer to come on about 5 hours before my anticipated departure and my Oil & Coolant are about 110. In Houston, I can't change my oil weight for the seasons or I'd be changing it every week. 80's last week, 30's and 40's this week. Forecasted to go back to 80's next week.

 

I plug it in at work whenever its at or around freezing, saves idling time & fuel warming up.( I dont pay the hydro bill there! ) At home I have it on a timer set to come on a couple hours before I leave.

 

I live in New England (MA) I never have plugged my truck in, I run 5W-40 year round and have never had an issue. I was in NH last year and started fine in -15*F. I never had an issue with my 6.0 either.