[Danishroy]

I live in Alberta, Canada. I spent the weekend at the in laws and the temp got to -38C over night. I had block heater plugged in over the day and a half we were there. It started up with the remote start the day we were leaving. Definitely sounded cold but it started first try.
Well now we get home and I plugged in the truck but didn’t realize my breaker on the garage outlet had popped and the block heater wasn’t getting power.
I went to start today and it wouldn’t start. It cranks and feels like it’s about to start but the doesn’t. I put a charger on battery to get it to full power but still not starting. I reset the breaker and tried after 2 hours but still same thing.
Any advice? I know my truck doesn’t like to be cold so I think leaving block heater plugged in will start it eventually but wondering if there’s anything I can do to help my truck not act like this.
This same thing happened 2 years ago when I forgot to plug in on a -30 night.
I have checked the battery a few months ago. It was fine.

 

[Action]

Guessing the oil viscosity is too thick for the ambient temp.
Because of that the engine does not spin fast enough to fire off the air/fuel mixture
With the heater the engine will spin faster because the oil is hotter and thinner. That difference may be between -30 something C and -10C.
At -10C the oil is thin enough that it does not create enough drag to slow the engine cranking speed.

This can happen because the oil is not the correct viscosity. OR because the oil is old. One of the things with older oil is the viscosity will change.

Not sure what the recommended oil weight rating. The working range of 5w30 is down to -31c.
Operating the engine below that range or close to it when the oil is older can be problematic.

Suggestions -
Keep using some kind of heater. Even a 100watt incandescent light bulb under the engine oil pan may be enough heat to do the trick. (I have done that when I lived in Michigan)
In winter you might go to a lower viscosity oil. like a 0w30 in the fall. Then change to the recommended oil weight in the spring. Likely this is discussed in the owner's manual.

You state the battery is good. A stellar battery is needed down to those temps. As are great battery cables and connections. There isn't much room for error at those temps. Dirty
cable connectors. Dirty battery case. Even slight starter bearing/bushing wear, restricted fuel filter can all be issues when the ambient is -20C or lower.

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[Danishroy]

But doesn’t block heater heat up the coolant and In turn heats up the block a bit? So engine oil wouldn’t get any heat right?
I am using Ford recommended oil

 

[Action]

The block heater will introduce heat into the coolant. If left on all night, some of that heat in the coolant will heat the rest of the engine. The goal for a block heater isn't to heat up the coolant or rest of the engine to inside room temperature. That would take a lot of power and be expensive to your power bill. The goal is to bring up the engine temp just a little. I don't have a spec on it and it would be like bringing the oil temp to -10C from below -25C.

If you are storing your vehicle outside in -38C ambient temps that is an extreme condition!
The oil specified (since you did not post) is 5W20 as listed on page 399 of the 2013 F-150 owner's manual.
2013 Ford F-150 Owner Manuals

5W20 oil is not fluid enough at -38C, or even in temps below -25C to allow correct engine operation. You risk damage even IF you get the engine started. That is too cold for the "recommended" 5W20 oil. Either change the oil or plug in.
0W20 Vs 5W20: Detailed Comparison - Oils Advisor

And one other thing. As oil gets older the viscosity gets thicker. Because it picks up blow-by. Changing the oil (in your enviroment) in the fall so you have relatively clean oil for the winter helps.

Using the oil viscosity recommended by Ford requires a block heater in extremely cold temps or the engine will not spin fast enough to fire off.
If a block heater heats the 5W20 weight oil enough to get to -20C that is all you need. My guess is a block heater will do a little better than that.
And like I posted above, I did the same thing in the late 1970s with a 100-watt light bulb under the engine of an older car (64 Galaxie w/ 390) that I parked in a barn. I was going to college in Western Michigan. Temps dropped very low one February. I was living (renting) on a farm and was able to park my ride in a barn. First very cold morning the engine cranked very slow. I ended up making a small fire in a bar b que tray and sliding it under the engine. After 20 to 30 minutes with a battery charger the engine fired up. The next night I used a "trouble" light. Basically a 100 watt light bulb at the end of a power cord. It generated enough heat that I could start the engine. OK still needed the battery charger. Used 3 light bulbs for the following 4 nights until the weather heated up. The heat of the incandescent light bulbs was enough to keep the oil fluid.

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