FE increase with 100% synthetic oil?
 

It seems many have changed oil, and switched to 100% synthetic or synthetic blends.

For those that switched to 100% synthetic oil, did you see any fuel economy (FE) improvement, and if so, approximate %? I would expect around 1-5%. Any input is appreciated;). Thanks.

Re: FE increase with 100% synthetic oil?
 

A search on this site will reveal many individuals claiming a small gain in FE with 100% synthetic oils. Mobil 1 0W-20 claims gains in FE with this oil over 5W-20. Some of us realize it is cheaper to use 100% synthetic oil with the longer use interval than using plain dino oil. Maybe only you can determine what works best for you.

Re: FE increase with 100% synthetic oil?
 

The '09 FEH owners manual says you will void your engine warranty if you use any oil other than approved 5-20W oil. In my opinion, synthetic oil will last longer but not give you better mileage. Dino or mixed with synthetic may give you the best mileage right after changing, but it will decrease the mileage as it gets older with more mileage. For all the reasons above, I change my oil with 5-20W Mobil 1 100% synthetic every 10,000 miles. My mileage stays constant the entire 10,000 miles, but I've never seen an increase in mileage after an oil change.

My '09 FEH has over 6,000 miles and I'm about to change the original oil with 5-20W Mobil 1. I've done all the oil changes in my '05 FEH with 55,000 miles with approved Motorcraft synthetic blend 5-20W myself and changed to Mobil 1 when approved 5-20W became available. Changing to Mobil 1 did not improve my mileage, but I feel engine wear is reduced with it. I've never had to add oil between the 10,000 mile oil changes. I do not under fill or over fill the oil level for any reason.

GaryG

Re: FE increase with 100% synthetic oil?
 

I have been using synthetic oil for 25 years. I have never seen a increase in FE. What I have seen is a dramatic increase in engine life over dino oil. This reason alone is why I recommend and use synthetic oil!

Re: FE increase with 100% synthetic oil?
 

I use the Mobil 1 for the long oil change interval.
I go 15,000 miles, which is generally 4 to 6 months for me, mostly highway, so not many cold starts, relatively speaking. I use 0w20.

For the 2005-2007 ( and I don't see why not any year ) Ford actually recommended 0w20 for persons who have cold starts at below 0'F.

Remember, the first number only applies when the oil is cold.

0w20 and 5w20 behave EXACTLY THE SAME after the first few minutes the car is running!

HTH,
-John

Re: FE increase with 100% synthetic oil?
 

On my two oil changes by the dealer, they installed synthetic. I haven't checked, but I assumed it was in the owner's manual.

Re: FE increase with 100% synthetic oil?
 

Yes, and Mobil 1 0-20w meets the exact Ford engine specification listed in my '08 manual so I changed to it as well about 1,000 miles ago. My MMH sees 3/4 of it's miles in the winter so using the lighter weight makes a lot of sense to me--if you live somewhere warm it probably wouldn't be worth it.

FWIW, My mileage has dropped since I made the change in October, but that is to be expected with the lower winter temperatures.

Re: FE increase with 100% synthetic oil?
 

I would suspect if 2 oils are 0W20 spec, one is full synthetic, the other not, there would be negligible difference in fuel economy. It's the 0W20 spec that governs, regardless of how the manufacturer arrives at it.

I've heard any 0W20 is by definition at least partially synthetic, just what I've read. I would think if you're sticking to your car's oil change interval there is no advantage to synthetic.

Re: FE increase with 100% synthetic oil?
 

Mobil 1 0W-20 is full synthetic and that is what the posters on this thread state they use for 10,000 mile intervals.

Re: FE increase with 100% synthetic oil?
 

Bill,

You might want to do some research before making that claim.
I am not going to debate the issue here, you can do the research right online and make your own assumptions from there.

And yes, they CAN print that on the bottle depending on what the "accepted" definition of synthetic is.

And yes, it is a very good oil.

08feh