Which engine do you have? If it is a 5.0 and you use 5w-20, it is semi-synthetic due to the nature of the processing.

My first oil change in the 3.5 I went with 5w-30 full synthetic because I heard it was better for the Twin Turbos.

 

That sounds correct. I have always heard that from manufacturers and oil reps alike, Honda and Royal Purple are examples that have advised a 10k mile break in. Also common advise is that once you go synthetic to never go back. Some engines come factory with synthetic but their engines are spec'd for it. Myself I have noticed on newer engines with very low viscosity oil that switching to synthetic no longer makes any difference in fuel mileage.

 

you can go full synthetic as soon as you want. its an old wives tale and the dealer is incorrect. Many new cars have full synthetic from the factory

 

Whenever the hell you please is the answer.

 

 

You need to change dealers. Any dealer that tells me an oil is 'too slippery' ain't gonna touch my truck with a 10 foot pole.

These aren't aircraft piston engines that break in with mineral oil, these are mostly broken in from the factory.

 

reality - most modern oils are a synthetic blend - which is basically a very clean and pure base oil with additives that are similar full synthetic oils.

I was under the impression that the basic motorcraft oil is a synthetic blend.

Now that run in nonsense - there is potentially a grain of salt with that. Most engines in modern cars are built in other factories - tested - drained - shipped to the install plant - refilled with the car - tested again.

So they've run and drained at least once and in a number of cases twice. Some of them are run at their factory on a special oil for their initial run only which is a no detergent thicker oil that runs through a serious filtration system as it runs though a set of engines at a time. In some cases it's the basic fill oil. Either Way this run is when most often the bearings are run in- rings have burnished and set in - etc.

Far more importantly the parts are finished to a higher degree than they were decades ago - such that places like valve guides are polished as installed in the heads and the valves are polished before assembly so they are smooth and clean at day one. Oil passages are polished internally with a abrasive putty, etc etc. Most of the break in requirement on a new car is not the engine but rather the transmission, axles and wheel bearings. Even newer transmissions are run against a dyno upon assembly - but nothing like the motor today.

So to that end I'd still advocate sticking with the stock fill oil for at least 2 oil changes and I suggest those occur at 1000 miles and at or near 4-5000 miles - after that use whatever meets spec and run toward the end of the OLM and you'll be perfectly fine. my 2017 currently has 13800 on it and tuned one year old on monday - it's last oil change was at 11600 and was oil change number 3 and is castrol syntec. first change was at 1200, second at 5300 and third went to 25% life remaining on the OLM. when it drops to 30% or there about I'll change it again. on the oil I might swap to pennzoil platinum or the ultra platinum next go as I use that in my other cars.

But more importantly I'm also going to trade out the transmission fluid,axle fluid, and coolant at or around 50K miles. As far as flipping back to a blend oil or going back to the motorcarft labeled stuffs after you use a synthetic - go a head if you want to. it won't matter much if at all. knowing the engine is meant to thrive on it - it is a good place to start. On my Daily driver I do about 1 oil change a year - to be fair it's more like a 10 month interval. - with an oil filter swap between oil changes.

 

With the 3.5L Ecoboost, if you aren't in a cold climate, is there any reason to run 0W-30 vs 5W-30? I've heard the 0W would provide slightly better MPG, while the 5W would provide a little better protection for the engine under heavy loads.

 

0W-30 is fine for the motor: the 0W means the pour point (thinner) for when the oil is cold, this is what you want on initial start up every morning, the 30W is the thickness it will achieve when warm--what the motor calls for! So running 0W-30 is great for out motors and that is what I run from day one after I bought my truck!!

The old break in story is Horse-***** for these modern motors from 10 years ago lol---I would run from that dealership as well--they have no clue, LOTS of vehicles come from the factory with Synthetic oil