Can you use 5w30 synthetic instead of factory 5w20 in your 2003 ford expedition 5.4?

Answer 1

NOIf you want to use synthetic then use 5w20 as recommended by the manufacture, unless 5w30 is an option as outlined in your owner's manual. They manufacture and sell 5w20 synthetic. With synthetic you can extend you oil change intervals to from 5,0000 to 10,000 miles depending on how and where you drive.

Addition..

If you are looking for better engine protection and are not worried about the minuscule loss in fuel efficiency use the 30 weight oil. A lot of manufacturers "RECOMMEND" a 0W20 or 5W20 oil... this is really to get the car to maximum fuel efficiency here in America.

Car companies love to claim they have the most fuel efficient vehicles. One way to meet EPA's MPG requirement is to use a lower viscosity oil such as 5W20.

You go to Europe same cars are running a 40W oil, and they are changing it at 10K