Ghettoeg6

I had always taken my car to get service at MB when it was under warranty..but now that it's not I changed my own oil the last time it was due

After reading manual and threads here
​, I picked up some m1 0w40 at Wal-Mart. I noticed my mpg went from 415 miles a full tank down to 360 miles after I did my oil change.

I checked the paperwork from the dealership after each service and I realized they had been using mobil1 5w40..would this be the cause of loss mileage?

​​​​​​I live in Midwest where it gets pretty cold. Thanks for the help

zeemob

My local dealer uses Mobil 1 Formula M 5W-40. I'm very satisfied with the mpg on my RWD. Took a 150 mile trip last night and averaged 33.1 mpg on the instrument cluster (both city driving and highway). On the other end my brother drives a 4matic and uses 0w40. He always complaining of low mpg. Says never seen 29 mpg on the clock, not even on highway driving.

There are lot of aspects to it beside just oil grade/quality. It also depends on tires, tire air pressure, alignment, RWD/AWD, air filter, engine tune up, weather, driving dynamics etc. It all adds up. That's just my 2 cents..

Ghettoeg6

thank you. i'm due for oil change now and will go back to 5w40 since that was what the dealership was using.

kajtek1

It is nice to talk about oil recommendations when we don't even know what engine they suppose to go
https://bevo.mercedes-benz.com/bevol...ets-sort1.html
Here is publication you should make yourself very familiar with. Oil recommendations can change every few months, so confirm it at every oil change.
Modern engine can be very sensitive to oil quality and if you don't believe it, - read about low-mileage, dealer-serviced Bluetec who seized filled with sludge.

Ghettoeg6

2010 4matic. thanks

kajtek1

Looks like the picture you posted come from 2010 manual? For last decade MB speck have 5 digits.
Once again, oil classifications and recommendations change in last years quite often any older diesels (I am familiar with) are on 6th generation of oils since their manual was printed.
Additional M1 is "famous" for generating high iron, so do some research if you care about your drive.

Ghettoeg6

if i'm reading that link you posted correctly, i should be using Mobil 1 Formula M 5W-40. thanks for your help!

cetialpha5

I wouldn't read too much into that, mine varies all the time depending on whether I drive in the city or the highway. Winter gas also has less BTU than summer gas. There's lots of factors, tire pressure, driving style etc. I wouldn't attribute that big of a change to the oil.

As long as it meets MB 229.5, you should be fine, if anything, I would think 5w40 would give you worse gas mileage, not better as it wouldn't flow as well in cold weather.

dlafever

I've switched to Liqui Moly 2332 Leichtlauf High Tech 5W-40 in all my Benzes, because I live in the desert and rarely see freezing temps. Honestly not sure if the 5W difference is much of a difference but it's on the approved list.