Block Heater How does it work?

I've started lots of equipment at 0 to -30 . It's definitely not idea to have oil like jelly but what do you do. Watching oil pressure take forever to rise from 0. But that's also with 15w40. Lots of newer stuff runs thinner oil and synthetic to boot.
They make stick on heat pads too. I've used those on a tractor without a working block heater. Stuck it on the oil pan. When you started cranking you could tell right away when that warm oil hit the rest of the engine it started turning over easier

 

I started my truck using a webasto to heat the engine at -34 with 15w40 in the oil pan. The truck fired up right away, but the computer shut it back down within about 30 seconds for no oil pressure.
There was some oil pressure, but only about 3 psi.
Turned on the webasto again, waited 20 minutes and started again. Shut down again, got about 5 psi that time.
Third time was a charm.
After that I ran synthetic oil in the winter.

 

it is alright as long as long as you are not using a straight weight oil. best to have a 10 or 0 w 30 in the sump. If you used the truck within maybe 36 hours, there should be enough oil to prevent galling and excessive wear.

 

Bonus: Heater blows warm air right away. I've drove in Artic conditions in AK. Once it hits -40°f you just park them inside.