The recommended oil type on the 2017 ford fiesta is motorcraft® sae 0w-20 synthetic blend motor oil. if by any chance you cant find this viscosity, you can also use sae 5w-20. some of the products that you can also use are mobil 1 advanced synthetic motor oil 5w-20 or castrol magnatec synthetic motor oil 5w-20. the purpose of engine oil is to keep the engine youthful and to preserve its life. what it does is cleans, conditions, reduces friction, and regulates the temperature. since it performs such a big task, it's important that you take good care of it. you can do this by changing it when it's time and topping it off when it gets low.
The oil type in an engine is critical. the fiesta has two different engine types and so if you are changing your own oil, you must know which type is yours. fortunately, they not require 5w-30 synthetic blend. any local automotive store will have the correct oil, don't forget the filter.