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

JXW

Joined
Apr 11, 2010
Messages
200
Location
Northern Michigan
Driving a 2016 528i Xdrive with the N20 motor, 4 cyl single turbo. I have now logged over 90K miles on the car. In the early days I was using the BMW ll-17FE oils, 0w-20. Since I have changed to 5w-40, Revenol VST at the suggestion from a person here at BITOG. Yesterday I acheived best MPG on a tank and started to think about the fuel saving properties of the new oils. In my operation, I could not discern a difference whatsoever from the 0w-20 for MPG in both summer and winter driving from the current LL-01 oil which has much higher HT/HS.

  1. I use COSTCO gas (93)
  2. My drive routes are always the same (highway 95%)
  3. My driving style
  4. OCI interval between 8k and 10K
  5. Tire psi are set and checked
  6. Four season climate from -10F to 90F

Looking to see if anyone has experience that shows the variant to the oil weights does or does not improve actual MPG?
 
Joined
Dec 31, 2017
Messages
10,528
Location
SE British Columbia, Canada
Yes, you have proven to the average driver that it makes no difference, but you didn’t defy the laws of physics. In controlled conditions, the measurements sanctioned by CAFE do show a small improvement for the 10’s of millions of vehicles out there. I run 5w40 in my Chevy 6.0 and also have not noticed any difference. Thanks for the post.
 
Joined
Apr 18, 2013
Messages
892
Location
Kevil,Ky
I am sure that the 0-40 must be providing a better protective coating for bearings and pistons and that may be what is causing your improvement in gas mileage. I just had new tires put on our 2012 Mazda 5 and our mileage went up at least 2mpg. Little changes make a difference. Her new tires are Falkens. Two tanks of gas now with same results. I keep records on each thing and every gas fill up since our purchase.
 
Joined
Jan 4, 2016
Messages
1,708
Location
NC
From what I've seen:
- When someone goes from 0w20 to 5w40, many posters talk about a hit to fuel economy.
- When going from 5w40 to 0w20, nearly everyone says that too many variables to notice fuel economy in real world.
Just an observation, make your own assumptions.

In my experience different brands of 5w40 gave different results. Back in 2014 when I had 2006 Pontiac Vibe AWD I tried every 5w40/0w40 on AutoZone/AAP shelf. All were same MPG as every 5w30 I used before. But with Valvoline MST 5W40 there was a huge drop in power (in lower RPM range) and MPG. MPG went from 28MPG average to 24MPG average. I dumped that oil within 1000 miles. Don't remember which 5w40 I refilled with, but MPG and power was back to normal instantly after the oil change.
 
Joined
Jun 26, 2011
Messages
1,024
Location
Florida
You really can't make blanket statements. My experience in changing viscosities is how much 'reserve power' a vehicle has. In a V-8 vehicle (or turbo), the difference in fuel economy is so slight you would be hard pressed to notice. But in something like a Mirage or Saturn, that are under powered from day one, there is a chance you will notice an improvement in mpg with a lighter oil.
 
Joined
Oct 27, 2018
Messages
506
Location
MD
I know 5w30 vs 0w40 gave me no difference in mpg what so ever. I might dare to say 0w gave me slightly better mpg (0.2 mpg) difference.
I log every tank to a .xx gallon level.
 

Attachments

  • Screenshot_20211009-135218.jpg
    Screenshot_20211009-135218.jpg
    44.7 KB · Views: 24
  • Like
Reactions: JXW
Joined
Apr 4, 2012
Messages
14,919
Location
Kendall, FL
My Mom and Dad each owned '95 Camrys. Dad always used 20w50 in everything. Mom forced Dad to go by the manual for her's - 10w30. Both made it to 300k miles. Their experiment "proves" thinner oils protect just as well as thicker one's do. No, just another anecdote. Unless done in a lab, there are just too many variables.
 
Joined
Mar 8, 2012
Messages
13,948
Location
Colorado Springs
I would be running Pennzoil Platinum Euro 5W40 in N20 considering it has lower amount of Zinc which is better suited for troubled timing chain guides on that engine.
 

JXW

Thread starter
Joined
Apr 11, 2010
Messages
200
Location
Northern Michigan
I would be running Pennzoil Platinum Euro 5W40 in N20 considering it has lower amount of Zinc which is better suited for troubled timing chain guides on that engine.
How does the PPE 5w-40 compare to the Ravenol VST 5w-40?
 
Joined
Jun 10, 2019
Messages
951
Location
FL
My Mom and Dad each owned '95 Camrys. Dad always used 20w50 in everything. Mom forced Dad to go by the manual for her's - 10w30. Both made it to 300k miles. Their experiment "proves" thinner oils protect just as well as thicker one's do. No, just another anecdote. Unless done in a lab, there are just too many variables.
20w 50 and lasted 300k wow, A bit thick for that engine.
 
Joined
Mar 8, 2012
Messages
13,948
Location
Colorado Springs
How does the PPE 5w-40 compare to the Ravenol VST 5w-40?
Both are exceptional oils. But PPE has Zinc below 800ppm and there is evidence that lower Zinc levels are better for timing chain guides. PPE is as current as it gets. GTL based oil so expect high HTHS, low Noack and good cold properties. Ravenol is also extremely stout oil but has more traditional additive pack with higher Zinc level.
 
Joined
Sep 23, 2008
Messages
10,083
Location
Ontario, Canada
I'll see if I can produce a data point.
I've got 8k km Mobil1 5W30 in the Focus right now, so when it gets cold (around freezing) I'll do a cold start in the morning and track fuel used during idle for 5min using the scangauge, then when I change to 0W20 I'll wait for a day with the same temperature and idle the car for 5 min and compare the fuel used in 5 min. I'd think the 5W30 will cause a measurable increase in fuel use but not all that much. I suppose at the higher rpms of actually driving the difference in oil drag would be a bit more and it could be estimated how much.
 
Joined
Feb 6, 2021
Messages
594
Location
Massachusetts
Driving a 2016 528i Xdrive with the N20 motor, 4 cyl single turbo. I have now logged over 90K miles on the car. In the early days I was using the BMW ll-17FE oils, 0w-20. Since I have changed to 5w-40, Revenol VST at the suggestion from a person here at BITOG. Yesterday I acheived best MPG on a tank and started to think about the fuel saving properties of the new oils. In my operation, I could not discern a difference whatsoever from the 0w-20 for MPG in both summer and winter driving from the current LL-01 oil which has much higher HT/HS.

  1. I use COSTCO gas (93)
  2. My drive routes are always the same (highway 95%)
  3. My driving style
  4. OCI interval between 8k and 10K
  5. Tire psi are set and checked
  6. Four season climate from -10F to 90F

Looking to see if anyone has experience that shows the variant to the oil weights does or does not improve actual MPG?
I've seen a difference using thicker oils with low viscosity index like 15w40, but virtually no measurable difference between 5w20, 5w30, and 0/5w40.

It's worth noting however that 99% of my driving is at full operating temperature, I'm sure if I did lots of short trips it would be noticably different, considering 0w40 is more than double the viscosity below 100F of 5w20.
 
Top