Real world MPG with 5w-40 vs 0w-20

[JohnnyG]

I like the VST a LOT and use it in my 2018 MB 2.0T. Recent trip to PGH got me 38 mpg highway so I'm a fan.
Too bad I'm not going to spend $70.00+ for 5 liters in the future.
I have ONE oil change left.

 

[wlk]

Been thinking about trying M1EP 0w30 in my Toyota 2gr-fe this oil change. Has had only Toyota and M1 0w20 since new (103k miles). Was interested to see if the engine is any quieter with it. Sounds like I might not notice any difference.

My K24 in my Element is quieter on 5w30 and even more with 5w40 but it is still a noisy motor for a Honda.

OP: no noticable difference in mpg's for us as well on the Element or Expedition

 

[Oldwolf]

I've been running M1 0W-30 in my 2gr-fe Sienna for a few weeks now. I can't tell any difference in noise level, sound or mpg. My feeling so far is that whether you run 0w-20 or 0w-30 it may not matter so much. Maybe my opinion will change next summer when the weather gets hot again. By then I may get the inking to try M1 0w-40...

 

[MSCH]

real world results and lab results are 2 different things.
that laboratory with a controlled set of conditions and parameters can prove one thing,
whereas the real world lab most people operate in tends to prove something else.

 

[FTTSHO]

My 2001 Chevy S10 Balzer with the the SBC based 4.3 v6 Vortec is recommended to use 5w30. It says it right on the oil fill cap and the owners manual. I’ve seen so many of these engines last 400k miles with 5w30, 20w50, 15w40, you name it. These engines just run forever even with lots of abuse, neglect, and on top of all that, horrible oil change intervals. I’ve even read on a forum of somebody running 5w20 on this engine, and they have not had any issues at all, and they did not notice any fuel economy gains at all.

But I use Mobil 1 Full sap 0w40 euro formula oil on my 4.3 Vortec. Why? Because I’ve been on BITOG too much, and apparently the M1 euro 0w40 is the holy grail of oils. Can run it on anything, and it’s able to clean engines out slowly, unlike most oils that only suspends contaminants thus keeping the engine clean, instead of actively cleaning the engine while suspending contaminants. My engine has crazy amounts of sludge in the lifter valley which I found out when I did my lower intake gaskets.

There’s a famous slogan for these 4.3 vortecs. “Power of a 4 cylinder, fuel economy of a V8.”

On my engine, there’s no difference in fuel economy no matter what oil I use. But on some engines, I’m sure it’s noticeable.

 

[Gillsy]

My 1988 "Shastro" hauled 5 peeps, and an 18 foot Four Winns w 150 hp outboard. Back in the day, it was 150 hp, but 270 lb/ft tq. I have no complaints with the mileage, or power. We put 150,000 miles on it before we let it go.

 

[CarbonSteel]

Your right foot
Headwinds
Heavier loads
Hills or mountains
Elevation increase or decrease
Speed increase or decrease
Under inflated tires

These are all things that will impact MPG more than a viscosity change ever will...

 

[Kira]

Add tire type/condition/inflation to that list....as well as cleanliness of vehicle (ha)....and whether it has a vinyl top or not (ha-ha).

Seriously, weren't there claims that textured vinyl roofs improved mileage back in the '60's and '70's?

"A car with its AC on burns less fuel that a car with its windows open", was another.

 

[kschachn]

real world results and lab results are 2 different things.
that laboratory with a controlled set of conditions and parameters can prove one thing,
whereas the real world lab most people operate in tends to prove something else.

True, but what it proves is that that it doesn’t prove anything.

 

[MSCH]

True, but what it proves is that that it doesn’t prove anything.

exactly.