Have u ever changed your oil (brand) and lost mpg? On my 2000, i have always used delo 15w40. I got some motorcraft oil same weight and ratings from wally world on sale and not only does it get less mpg, it also seems to smoke a little now. When the delo would be due for a change, it would drop off on mpg but never from the start.

Of course, I am going to go back to delo but was just curious if anyone else has run into this?

 

I've never run Motorcraft (except when I took delivery), but I haven't noticed any MPG differences when trying out Rotella / Delo / Delvac / Valvoline oils in my truck. I even had UOA's done on each of them and didn't see any differences to cause concern.

 

I used Motorcraft on my first oil change, and then went to Rotella T6. No change in MPG.

 

I had a similar problem with motorcraft oil. Was also slower to start and I used more of it. Switched back to Rotella T6 and everything went back to normal. My 99 didn't seem to care what brand I used.

 

When I first got my truck I used motorcraft oil I didn't not notice a change going back to rotella but the motorcraft used about 3 qts in 5,000 miles vs the rotella using about 1.5. I also noticed my injectors seemed happier with rotella and not as noisy. No change in mileage though.

 

Never noticed any change here either....

 

Recently the last two oil changes that I did at 3000 miles because I don't drive far the truck has seemed harder to start and sluggish. Thia change put Valvoline 15w40 and it runs a little smoother and starts easier. The motorcraft just doesn't seem to hold up to the stronger t500 vs the 15*. Never noticed it till I put it in.

 

Your driving habits and the condition (amount of wear) on your engine internals can certainly make your particular truck have a personality for different brands of oils where someone else may not see the same results due to their own driving habits and amount of wear inside their engine.

General rule of thumb, though, is that it takes at least two oil changes to get a "true and complete" conversion to a new oil. In your first oil change with a "new" oil, it is not necessarily uncommon to sometimes see increases in your wear metals if the "new" oil has a stronger additive/detergent package or is produced from a higher quality base stock because it will be sort of cleaning out your engine from the residuals of the lesser quality oil. Differences in the oil's base stock and/or additive package (anti-friction components, viscosity index, etc.) can certainly result in changes in fuel mileage.

That being said, given what you've observed, with your first run on the Motorcraft, I would do exactly what you're implying.... either change back to the Delo or move to one of the other higher quality oils already mentioned... (Rotella T5 or T6, etc.).

After doing a few minutes of quick research, the Motorcraft oil is made by Conoco-Phillips/Kendall, and their Group III base stocks appear to be sourced from SK in Korea. In Canada, however, the Motorcraft branded oils are made by either PetroCanada or Imperial Oil, and I am not yet sure where either of those companies are sourcing their Group III base stocks. The point here is that Motorcraft is sourcing their oils from low-cost bidders, and those contracts are established separately by geographic region. The bottom line is that their oils, although made to industry and SAE and/or API standards, you can potentially find different levels of quality by region. Admittedly, the same thing can be true of the brands from the "majors" (Exxon-Mobil, Shell, etc.), but I am not versed on the details of those companies at this time.