Ok. So far I've read 429 pages of this forum and I still don't have a definitive answer for what is the proper oil for these modular engines.
I've got a 2003 FX4 with a 5.4. It has about 50,000 miles on a new engine.
So what say ye?

 

Owners manual

 

From what I saw, the recommended oil is etched on the oil fill cap.

 

From the 2003 latest printing. Witch you can download from the link in my sig. I use motorcraft synthetic blend.

Use SAE 5W-20 engine oil. Only use oils “Certified For Gasoline Engines” by the American Petroleum Institute (API). To protect your engine’s warranty use Motorcraft SAE 5W-20 or an equivalent 5W-20 oil meeting Ford specification WSS-M2C153–H. SAE 5W-20 oil provides optimum fuel economy and durability performance meeting all requirements for your vehicle’s engine. Do not use supplemental engine oil additives, cleaners or other engine treatments. They are unnecessary and could lead to engine damage that is not covered by Ford warranty.

 

You will not get a definitive answer, just a bunch of opinions (including mine).
Some will say use what the engineers/designers/Ford say to use (5w-20).
Some will say use what was originally spec'ed by the engineers/designers/Ford when the engine was designed (5w-30).

The fact remains that billions of miles have been run on these engines with both oils with minimal oil related problems so long as the oil is changed on a regular basis.
Use what you want.
Research if you want.
5w-20, 0w-20, 0w-30, 5w-30, 10w-30, conventional, blend, or synthetic, really does not matter so long as it is changed regularly (which is another argument in itself) and kept at the correct level.

I personally do use 5w-20.
Why, because it works and there is some evidence that hydraulic actuators for the timing chain pressurize faster with 5w-20 vs 5w-30.
Enough to make a difference in 300,000 miles, no idea, but does not hurt to use it.

 

I use 5W-20 only in mine. Why? 1) Ford released a TSB (click link below) which recommended switching from 5W-30 to 5W-20. 2) I live in a state that gets to single digits at times in the winter. 3) Three of my other four vehicles have a 5W-20 manufacturer recommendation, so it makes buying oil to put on the shelf a lot easier.

https://www.allfordmustangs.com/foru...-7-2001-a.html

The truth of the matter is, since you live in Mesa, 5W-30 is probably just fine for you. The most important thing to do is buy a good filter. Do your own research if you'd like, but Motorcraft and WIX are your best bets here. The O'Reilly house brand (Microgard) is actually made by WIX. Stay away from the orange can.... if you don't believe me, Youtube it.

 

Why the proper oil is so important

The modular engine is an overhead cam design. Two very long timing chains keep the camshafts in time with the crankshaft. Because of the length of the chains, guides are needed to reduce movement. They also use a hydraulic tensioner to keep each chain tight. Oil pressure moves the tensioner which controls slack in the timing chains. These components rely heavily on proper lubrication from the engine’s oil.

Ford originally specified a 5W30 motor oil for the engine. They soon found this caused oil consumption and possible catalytic converter problems. This caused a change in the specification to a 5W20 or a 5W20 synthetic blend. It is also believed the lower viscosity oil can travel to the timing chain tensioners more quickly. The oil filter they designed for the engine also has a specific anti drain-back valve and for good reason.
With a substandard oil filter the engine oil may drain back to the oil pan when the engine is turned off. A lack of oil pressure means the tensioners cannot immediately tighten the timing chains on startup. When this occurs, slack in the chain tends to jerk and the plastic timing chain guides can break.

 

Let’s not overthink this. Cat converters were being “poisoned” by the metals (phosphorus and zinc) that are for the most part no longer present in oils. The oil consumption issues were generally from poor quality valve seals. The prescribed “fix” for that across the various modular engine platforms is 5w-30 or even 10w-30 oils to soften the seals up.

5w-20 also tends to break down sooner than 5w-30. Logic would dictate that this would be the better choice in keeping tensioner tighter for longer. Especially for someone like blupupher who lives in a toasty concrete jungle.

Ford went to 5w-20 purely for CAFE brownie points. Their beancounting issue isn’t your concern. I don’t recall Ford having so many timing chain issues before 5w-20 became chic.

 

"Recommended" is in your owners manual.

The forums have some suggestions of what is recommended, and major suggestions of what is 'right'.

If you do not have an owners manual, you can find a PDF version available online for YOUR particular model.
Look for it and use what it says in the manual for your book.

The manual probably says Ford synthetic blend 5w-20. Maybe it says 5w-30.
What else do you need to know? Your question is quite loaded....unless you truly are asking 'What Ford Oil do I use", which is what it sounds like you are asking using the word "Recommended".

 

This is probably not correct, as a general statement.

Driving style probably has more affect on engine life than oil choice. Pick a high quality brand, and use the engine in a way that makes it last, if you want it to last. You can't really make a choice unless you define what you're trying to achieve.