Oil Recommendations

I have a 2015 GT. It sees mostly city miles. When I first purchased it, it was getting 13.9 MPG. Then, last year for a short time it bumped up to 14.2 MPG. Now it's down to 12.8 MPG. Driving pattern hasn't changed.

I've noticed that it gets 14.5 to 15 MPG for the week after an oil change. Oil changes have been done at the dealer and they use a blend of Synthetic and standard oil.

Do any of you have a preferred oil that you use on your S550 that gets better city millage?

Thank you

I average 18.5 mpg in mixed driving. Seen it jump to about 23 mpg when more highway is involved. Has a lot to do with the 3.73 gearing.

I just changed the factory fill around 6800 miles with Pennzoil Ultra Platinum Synthetic. No real noticeable differences I can tell, but the reviews on that oil are pretty stellar and it was hard to say no when there were big rebates on Amazon per quart or gallon.

There's so many good oil choices and I would suggest searching on the forum because everyone will share their opinion and this thread will just blow up into another "What oil do you put in your car?". Nothing is really wrong as long as you are following the weight and viscosity ratings. This engine is thirsty when it comes to gas. Nothing you can do except get an Ecoboost, lol.

I also like the Pennzoil Ultra Platinum for the combination of quality and price. I am a shop owner working on cars for almost 30 years now FYI. I used it on my 15 PP and now my 18 base A10.

Pennzoil Ultra Platinum for me as well. Though, I wouldn't say it gives you better gas mileage. The type of oil you use is not going to have a big effect on mpg, generally speaking.

It's a combination of how heavy your foot is, the type of driving, and traffic you deal with.

There's wayyy to many variances in city driving to compare week to week. One day you can get stuck at a light longer, or have a little bit more traffic or have pressed the gas a bit harder than usual. No way can you replicate the same exact driving pattern 100% on a week to week basis.

Now if you were cruising on the highway at the same exact speed and same exact stretch of road I would say then you can compare readings. Oil doesn't have much to do with this unless you put in a vastly different viscosity of oil then you might get worse mileage (eg. going from 5w20 to 5w40) so it's pretty much the way you drive.


As far as oils, I prefer Amsoil or Motul or Penzoil Ultra.

Motorcraft synthetic blend 5w20 but it doesn't have much to do with mpg I get 19 to 22 with 3.73 pp gears. Do you have any mods? Intake tune?

Use full synthetic whatever oil you get. Nothing compares.

I've done a lot of research and for 5W20, Quaker State Ultimate Durability tested better than any other 5W20 including Amsoil, RP, M1, Etc... At a lower price.

There are many threads on oil here. A ton of different recommendations. Just do your own research and find out what meets your budget and demands.

Mine still gets the motorcraft synthetic blend too..averaging 21.5mpg.. oil wont matter much on your mpg variance.

No mods or tunes. Still under extended warranty. Must be the winter/summer fuel blends. The pony gets better millage when it's cold and foggy out.



Thanks for the advice all.

I haven't noticed one bit of difference in fuel mileage between MC 5W-20 Semi-syn and Penzoil Ultra Platinum 5W-20. Both oils meet Ford's OE spec obviously. MC is much easier to find however in my area and is a better oil than most think even if it's not as good as PUP 5W-20.

I did notice a bit more pronounced ticking that would occasionally occur with the PUP 5W-20 that does not occur with MC 5W-20. I ran PUP last fill and switched back to MC 5W-20 this fill out of curiosity.

I don't believe it is harmful and it only occurred a low RPM / idle when the engine was un-loaded (neutral). May be a little bit of cam phasor tick or lash adjuster tick when pressure it a at a minimum.

Other than that from an efficiency standpoint there is no measurable difference. Engine protection with modern oils is far more dependent on driving conditions and oil change intervals than anything else. Most of the base stocks now with their additive packages are good enough.

Different engines and conditions however see different results so some testing might be necessary to choose the best suited oil for your application. I'd stick with what is available for a reasonable price in your area and just change it regularly.

pctek said:

No mods or tunes. Still under extended warranty. Must be the winter/summer fuel blends. The pony gets better millage when it's cold and foggy out.



Thanks for the advice all.

Click to expand...

It should be the opposite, no? Colder air is denser which requires more fuel to burn. I was under the impression that, all else being equal, fuel economy should increase when its warmer out.

RedRyan98 said:

It should be the opposite, no? Colder air is denser which requires more fuel to burn. I was under the impression that, all else being equal, fuel economy should increase when its warmer out.

Click to expand...

i believe the theory would be cool dense air increases HP. thus decreases need to apply as much throttle to achieve same results. as we all know a cooler intake temp will increase HP.

RedRyan98 said:

It should be the opposite, no? Colder air is denser which requires more fuel to burn. I was under the impression that, all else being equal, fuel economy should increase when its warmer out.

Click to expand...

Altitude has more of an effect on it. Just ask the people in Colorado running at the drag strip. Forced induction is your best counter to that when you start climbing up in altitude.

Not necessarily the temp of the air. It's the amount of air. Although, when it gets to be 102 degrees here, I'm sure I'll get some timing pulled if I'm idling too long.

I made a thread containing a poll which asked what type of oil everyone on the forum uses, and it got great responses. Go check out the maintenance section of the forums.

For myself? I also use Pennzoil Platinum/Ultra Platinum.

Uh oh, not another "what's the best oil" thread. These are highly subjective.
I use Godzillas Super Duper, Mega Ultra, Unobtainium with Diamonds and Quasi Gold and Pixie Dust Oil and it's the best!
Sorry, couldn't help myself again. My bad.