So I have a 04 F250 5.4 3V with 116K and have always used MOBIL 1 5w-20. In the last month or so I have been told 2x I should switch up to 5w-30 hiogh mileage anyone heard of this and id there really a difference from high mileage to the regular? Thanks,

 

High mileage motor oil has additives that cause seals to swell a little bit to prevent/stop oil leaks. If you are using synthetic oil and you don't have any oil leaks, keep doing what you are doing.

Now, I know i am probably going to catch some hell over this, but here goes. Water cooled, gas engines are far better served using 5W30 over 5W20. There is no difference in the engine designed to run on those 2 weights. 5W20 was designed to try to eek out a little better fuel economy for the manufacturer's fuel economy averages. 5W30 does offer better protection. I run 5W30 in every Ford I have, or had (except my diesels) since they were new. You can switch to Mobil 1, 5W30 with confidence. Again, if you have no oil leaks, you can bypass the high mileage motor oils.

 

Stick with the viscosity that is recommended by the Ford engineers. People that might say "xxx offers better protection" or "I've been running it for years with no problem" are not smarter than the Ford engineers. It's quite foolish to recommend something different for a stock non-rebuilt engine.

-- Dave

 

Your 04 was a few years after the switch to 20 weight recommendation. There was no change to any specs as far as oil passages, bearing gap, ring tension from the '99 that recommended 30 weights. The 20 weight recommendation was for CAFE MPG averages.
You can switch to an HM oil if you want. But as stated, if you have no leaks, and aren't using oil, you won't really find any benefit from it. I'm guessing at 116K, if it's had a steady diet of M1 5w20, the engine is in good shape. Keep on with what you are doing.
The 20 weights are pretty stout. You begin to have the dog chasing it's tail when the engine ages and starts polluting the oil with fuel, blow-by and carbon. The oil film has to be thicker than the ingested dirt, so moving up a grade is common to extend the life of a seasoned engine.
The argument between 20 and 30 weights gets very cloudy if you dig into oil specs. Some 20 weights are really at or over the line of a 30 weight spec, and vice versa. Many 30 weights are shearing to a 20 weight after a bit of use.
HM oils tend to hug the maximum thickness for their grade weights. And they (almost) all have a bit of ester in them to swell seals slightly.
Either are fine in your '04, you won't see a difference either way.

 

Exactly. 5W20 was recommended (reference a Ford position statement released some 18 years ago) to reduce internal drag on engine components for CAFE mpg.

 

Agree with above. More mpg and power is why they recommend that weight.

Besides that if you are getting close to a quart use between changes, working the motor hard and/or in a hot climate it wouldn’t be a bad idea to up the weight.

I would consider the high mile stuff if you are getting some seepage or worried about internal seals. Sticking with the same oil brand and/or model over time generally avoids this.

 

A 2004 Super Duty would have had a 5.4L 2V engine, not a 3V engine. The Super Duty trucks didn't start using the 3V engines until 2005.

 

F250's and above have never been included in CAFE standards as far as I know. What would be the reason for the change if not for CAFE standards?

 

6.2 engines use 5w20 from 2011to 2015. Starting in 2016 5w30 is recomended. Is there a difference in the engines?

 

Like the time they designed the Pinto firebomb

 

I've been running Motorcraft synthetic blend 5W20 in my 2010 5.4 truck for many years. It does not use any oil between changes or has any leaks so I will stick with what Ford recommends..