Mobil 1 0W-40 or 5w-40 in 617 - PeachParts Mercedes-Benz Forum

WD8CDH · #1 06-09-2009, 04:30 PM

I noticed that Mobil recommends 0W-40 for the W123 diesel motors but since it has a lower diesel spec than 5W-40, I emailed Mobil asking which one was really better. It took a couple of tries before I got something other than the blanket answer of either would work. Here is the response that I got:

Ron,

The Mobil1 Turbo Diesel Truck 5W40 motor oil would have better soot control and be the best choice for diesel engines, drain intervals would be the same.

-MJ

Ron wrote:
> I know that either product meets all of the requirements for the
> engines, but which one would protect the engine better or have the
> longest oil change interval? Will one or the other handle more soot
> loading? Would there be any difference in deposits in the combustion
> chamber?
>
> Thanks,
>
> Ron
>
>
> -----Original Message-----
> From: ExxonMobil [mailto:mobilproducts@ourdataworks.com]
> Sent: Tuesday, June 09, 2009 10:36 AM
>
> Subject: (no subject)
>
> Ron,
>
> Either product can be utilized can be utilized in both of these
> vehicles without issue, they meet all the requirements for the older
> vehicles that you have listed. So it may very well come down to what
> is easier for you to locate and purchase. The Mobil1 0W40 motor oil
> meets API "SM/CF"
>

compu_85 · #2 06-09-2009, 05:34 PM

Use the 5w40. The 0w40 oil is almost a 0w30, wheras the 5w40 is well into the 40 weight range.

When I used the 0w40 oil in my TDI the engine sounded like it was cold all the time. I stick with 5w40 now (the 0w40 oil is specifically approved for my engine though)

-Jason

pawoSD · #3 06-09-2009, 05:35 PM

Yep, use the 5w40.....the 0w40 is too thin. It makes the 617 sound clattery (probably not a good thing)

Oracle12345 · #4 06-09-2009, 05:42 PM

sounds like a sales pitch to me. I just stick with 15W-40

argus445 · #5 06-10-2009, 08:26 PM

Quote:

Originally Posted by Oracle12345

sounds like a sales pitch to me. I just stick with 15W-40

0w20 really lets the bearings and rods sing..

pawoSD · #6 06-10-2009, 11:45 PM

Quote:

Originally Posted by Oracle12345

sounds like a sales pitch to me. I just stick with 15W-40

In colder climates the 5w40 is a great thing to use, it cranks over much faster in the cold temps....and oil pressure comes up faster. I'd especially recommend it for the colder climates.

winmutt · #7 06-11-2009, 09:40 AM

Some of the VW TDI guys started using 0w40 when it first came out and reported high metal content in their oil analysis.

WD8CDH · #8 06-11-2009, 10:13 AM

Quote:

Originally Posted by pawoSD

In colder climates the 5w40 is a great thing to use, it cranks over much faster in the cold temps....and oil pressure comes up faster. I'd especially recommend it for the colder climates.

I agree. I don't use 15W-40 any more even in the summer. It's usually Rotella 5W-40 or Mobil 5W-40 year round in my cars. Since I don't go with ultra long drain intervals, I more choose brand between the two by cost.

FYI, in an emergency I have found that most Mobil dino oils for regular passenger cars have at least a CF rating. Most other brands are only SM (gasoline only). If I was stuck needing a top off, I would have no problem using any Mobil 10w-40 oil in my W123s. It's got to be better than any diesel oil from the early '80s.

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