I have a 2016 Ford F-350 6.7 with 42,000 miles. I was wondering what temperature you should be plugging in your diesel?

 

For me, 0F or below. Starts fine above that. Not sure what the manual actually states.

 

Ok, so I had to go look.

In the diesel supplement it states: "An engine block heater is recommended at temperatures below –10°F (–23°C)."

In the owners manual it states something slightly different: "Note: The heater is most effective when outdoor temperatures are below 0°F(-18°C)."

With regards to how long to run it:

"The heater uses 0.4 to 1.0 kilowatt-hours
of energy per hour of use. The system does
not have a thermostat. It achieves
maximum temperature after
approximately three hours of operation.
Using the heater longer than three hours
does not improve system performance and
unnecessarily uses electricity."

 

Check your manual but I believe that the 6.7 does not require being plugged in above -10F, however, you may want to plug it in above that temperature since the truck will take less time to warm up. I do this about 1-1.5 hrs before I leave the house and I get heat in the cab sooner. Most mornings I have a short commute to work so the engine gets to normal operating temperature sooner.

 

I'm pretty sure Ford has a specified temperature range but as others have stated it's really a point of keeping you warm for that ride to work in the morning even with the supplemental Electric interior heater. The only thing I can tell you I've had the truck start as low as minus 21 below standing temperature not wind chill with no problem after a good night 16 hour soak just keep your batteries up I changed them too AGM batteries in my 16. Believe me I wish I could have plugged it in but sometimes job sites don't even have power other than a generator and the contractor isn't going to allow you to plug your truck in LOL also anti gel is very important at those temperatures I don't care what brand you use just use one you'll never have an issue with jelling fuel filters. Also it becomes quite an argument around here I recommend a full synthetic oil you'll never have an issue with a slow turn over 5w 40 take care

 

I have a seven mile commute to work, all 25-35mph, I plug in when in the 20s and have a front grill blanket, otherwise it never gets up to temp and is a very chilly ride. I do have it on a timer/relay as well.

 

I live in Wisconsin and we see plenty of cold weather. I've never plugged either of my 6.7L trucks in and have never had an issue. Does't mean that I am correct, just stating what I do. Been driving a 6.7L for almost 6 years now. Drive it every day. Takes a while to warm up but starts easy, even when really cold.

Bruce...

 

I plug in below 20. I only do this to get heat sooner, as I don't get heat between my house and work if it isn't plugged in.

That said, I've started my truck many times at -20 and had no issues at all. I recall reading an article that talked about the 6.7's being tested and designed to start down to -40 without a block heater, though it is recommended as others noted.

 

What js139 said... The 6.7s start down to -40F (which is also -40C) and there are some youtube videos with starts colder than that. I have gotten the wait to shift with a 10 second or so countdown at around -20F, if not plugged in. Obviously, if you remote start for a few minutes before you make it to the truck, you'd never see a countdown. Oh the "Please wait" isn't a suggestion, it won't let you shift until it's ready to let you shift.

Last year I was spoiled as I had heated garage. This year, once again, I am parking outside.

Like js139 - I try to plug I with the temps are below +20F. The State of Alaska recommends this temp - even for gassers too. Supposedly it helps with fuel economy and with emissions. I wish I had a dependable timer, so most of the time it's plugged in right before I go to sleep - so 8 hours. Which I did last night. Now it was warm this morning at +13F and after a few minutes of a remote start idle time it was nice and toasty when I got inside. However it wasn't that way the other days I didn't plug in at +13F (or colder).

FWIW, while the motor starts in the sub zero cold, I like the sound of the way it starts better if I plug it in. Add the benefit of not scraping the frost off the windows in the morning and getting into a warm cab and for me it's worth it to plug in.

 

My truck is plugged in all night every night if it's below 40. I hate getting in a freezing cold truck. If I'm somewhere it can't be plugged in its not a concern, but if I can plug it in I will. I also drop the baby off at daycare in the morning and he likes a warm truck too. But my routine started long before him. I'l pay the electric bill, it really doesn't make a big difference.

 

I like the way you think.
The temps get in the forties, my truck is plugged in. I like the fact the heater gets warm right away.

 

To me it is not so much about creature comforts as it is about doing what is best for the engine. Oil will circulate better in a warmer engine and that should result in less wear.

 

Yeah I know 0(ish) is the official time to plug in, but I too like to do it anytime that temp starts dropping below 38 to 40 and I know I need the truck.

I went a little over board and setup thermostat to an app that controls when my heater comes on. This way if it is 4:00am and I need to drive at 7:00, and the temp is below 38 the heater will come on. Of course now I just need to find an app that will actually plug the truck it by itself.

 

Curious, why don't you buy a $5 timer and save a more than that in a month? Not bashing, just throwing it out there.

Personally, I ordered by 6.7L without the engine block heater...it's parked in the garage, so even when it's 0 outside, it's still about 50-55 in the truck.

 

Hey Dakster! Good seeing you. Where did you end up with your house? Hopefully close by. We should catch up before life gets busy again after the holidays.