quote:Since you live in the land of the Alberta clipper, I am sure you have a cold weather package on the jeep?? Block heater,and oil pan heater. Even with the best oil,at -40,warming up things before you crank the engine is best. I know of propane heaters that are used when no electric is available by some. After all the mods you have performed thus far,a cold weather package would be a prudent choice.
Also, why is 5w-20(petroleum) better than 5w-30 synthetic,the cold weather spec is better with the 5w-30 syn. Or why not use 0w-30 synthetic at least? However,it does depend on the brand and so forth. Once your engine heats up the 5w-30/ 0w-30 is better for the sake of argument. Just look at the specs.
I do have a block heater,a 250w pad heater under the oil pan , battery blanket and the most important heated seat.