I just bought a 2006 F150 with the 5.4l and due to the notorious issues I ended up getting a remanufactured engine. I am curious what engine oil is best for these picky beasts. I honestly want to use Motorcraft 5w-20 Synthetic Blend, but am curious about a couple things. First, I live in NW Montana, where the winters get well below 30 degrees for most the year. would the oil I want to use be the best option for the 5.4l? Lastly, during the summer months (it pretty much goes from winter to summer here) it can get in the 90's +, so I want to keep a year round oil. I am more concerned about the oil making it to the top of the engine during winter. The one I just replaced with the reman had 130k and every issue you can think of with the 5.4l that are possible, so I opted to start fresh. I also replaced the entire exhaust because the cat was pure junk. So everything from the engine to the exhaust is brand new. I even went so far as to replace every single fluid (including f&r dif's), got a new PS pump, alternator, new radiator, new brakes/rotors/rims/tires/steering & suspension incl a level for the front. It's basically been rebuilt without replacing any electrical (fingers crossed) so I just want to get the most life out of it so I can focus on the rest of the truck (body and interior) now. This thing needs some TLC and some bedliner ASAP. I spent A LOT doing this, but am still very skeptical about the engine oil. Any help or advice would be great. Thanks.

I also posted my truck in the picture section with a little detail about future/current upgrades.

 

5 w 20 is the correct oil. MOTOCRAFT SEMI SYNTHETIC is a excellent choice. Go with the MOTOCRAFT filter also... the "5" means the oil has a viscosity similar to 5 weight oil for easy winter startups ... the 20 is 20 w viscosity when hot ( summer or properly warmed up motor) which is what the motor clearances are designed for... an excellent choice.

 

I agree with that but I know it gets a heluva lot colder there than 30F - like maybe -30F once or twice a year. I would consider running 0W-20 synthetic from October to March then 5W-20 for the milder half of the year. This is assuming the truck sits outside at night or in an unheated garage.

 

^^^^^
agree with that
plus cold climates bad for sludge build up do to extreme temp difference and condensation in oil .You can't go past 3/4 months even if you are below 5k miles . I know its hard to change oil when its freezing out .The engine runs up to 200 deg f then every night down to 0 or so . Thats condensation conditions get that out of there before it turns to cake frosting .