5w-30 semi synthetic will protect in this country for temps you will have.
but mineral oil from new, does not have the properties to resist deteriation, plus cheap oil does not have the addatives required to meet any of fords spec, and is generally not good at low temps.
the ford handbook even says to choose what oil you require for temps.
using a sae40 oil is 30% thicker than a sae30 oil, so what reason would you want to use a higher viscosity oil in your engine that is recommended
age
using a higher viscosity engine oil will only cause more problems