Originally Posted by Crumm
If you cannot plug the truck in at -30 then you really need to switch to Synthetic oil. Regular oil is OK at those temps with a oil pan heater but with no heat the regular oil gets so thick that engine damage may occur at start-up. With synthetic oil the engine will get lubrication even at -60 where the regular oil will not flow.
Twice last winter my truck didn't start EVEN when plugged in all night. My truck has the engine block heater, oil pan heater, and battery heaters. It was about -45°F to -50°F. Even with the block heater and oil pan heater, 15 quarts of oil is difficult to heat at those temperatures. I had conventional dino 10W-30 oil and I think it was too thick. I'm going synthetic this winter. It warmed up to about -40°F and the truck started fine. No battery charging or anything, the ambient temperature just warmed up a little.
I also need to check what size (wattage) oil pan heater was installed. It could only be 75 or 100 watt. I wonder how big I can go without cooking the oil?