"On my personal vehicles 2% soot with 0W-40 synthetic oil is simply indicating oil change needed now."

Do you really use 0W-40 oil in your diesel or was that a typo?

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Mobil 1 0w40 is specifically approved for MB diesels.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Yes...for many of our cars it's THE recommended oil...though I use 5w40 with no concerns whatsoever.

__________________
14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I am about to claim victory. Back in 07 and 08 when I was battling the 3000 OCI guys, it seemed like 1/2 of the posters here did 3k mile OCIs and the others did 5k mile OCIs. Now I see quite a difference.

It looks like the 3k mile OCI is finally dead. Common sense finally prevailed.

Yes, especially in winter.

Exclusively Synthetic oil, unless I am breaking in a rebuilt engine.

During the summer I have no hesitation using 5, 10, 15, or even 20W40.

The qualifier is what is cost effective for you.

My average driving is wildly variable across the fleet 1k - 35k miles per year.

The least used vehicles have 0W40 at all times, and are changed at 9k miles regardless of months/years.

The highest use vehicle has 0W40 in winter, and usually 10W40 in summer.

.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

Soot level is not the only reason to change the oil. Everyone seems to forget about TBN, additive levels, viscosity breakdown, sump size, filter capacity, and all that other pesky stuff. 3-5kmi OCI's are fine with dino oil of the proper API rating, for normal service, no oil analysis required. It never hurts to change more often if you want. At the other extreme, changing the filter annually and topping off (never actually changing the oil) is ridiculous.

If you want to do extended OCI's, knock yourself out, but recommending that for basically everybody else on the forum is not smart. You don't know their car, what oil they are using, their driving habits, oil consumption rate, engine condition, etc.


As I've repeatedly stated, for the record, I personally do extended OCI's (10kmi) on my cars, with analysis every time including TBN and F-soot, and only with Group IV/V synthetics. Analysis indicates I could probably go longer but 10k happens to be a convenient interval for me. That's just my preference. Y'all can do whatever you want.

Neither my IDI vw or IDI Mahindra turn the oil black like the Mercedes does. I blame the amount of oil still in the system when I change it. I would figure that the design would allow for changing it but I guess it doesn't.

AS far as changing the oil every 1000 miles. 2 gallons every 1000 would pay for a rebuild at some point wouldn't it. I change my oil about 3-5000 miles. Like others I scored M1 5w40 truck oil in January.

__________________
85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

Yes, the oil turns black quickly in MB diesels. However, the oil will look black even with a tiny amount of soot present... usually within a few hundred miles. This is normal and it may be due to the leftover oil in the system, particularly on the turbo models with oil coolers which do not drain during the oil change. Don't worry about the appearance of the oil; if you really are concerned, get an oil analysis at your typical change interval and see what the results are.

Hi, my point is that the 300D gives me black oil within seconds after a change (due to residual oil). My vw or tractor may go 100 hours before getting dark.

__________________
85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

According to the Technical Manual when you fill an Engine that has never had Oil in it you will add one more liter of Oil.

That means when you do an Oil Change there is 1 liter of dirty Oil left in a 617.952 Engine.

My Volvo diesel (1982) does not get the Oil as Balck of discolor that Oil as fast but the Block was rebuilt and rebored for oversized Pistons so the Compression is near like new. It also has a different type of Precombustion Chamber and no Turbo Charger.

If you rebuild a Turbo Charger you will find that were the Oil sprays on the inside of the Bearing Housing on the Exhaust Side to cool it there is crusted Carbon Build up from the Oil Burning there over time. That must also help to make the Oil Black.

__________________
84 300D, 82 Volvo 244Gl Diesel

And could not have stated it better.

.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

Well now I am going to claim victory, given that whunter is doing 9k mile OCI and gsxr is doing 10k mile OCI.

And gsxr admits that oil analysis indicates he could go further. Yes, gsxr, and if you changed the filter once a year and topped off, and kept doing your oil analysis, you'd finally figure it out.

And even a year ago, Edmunds joined the crowd....

Stop Changing Your Oil! - Edmunds.com

I still laugh when I think about the Texan who still posts on this forum who used to advocate changing your oil every 3000 miles, with a hot engine, and leaving the drain plug out all night long just to get all of that evil 3k miles oil out of the engine...sort of like an exorcism. What a hoot!

Um, actually, no... by about 12-15k (on my cars) the analysis would indicate a change is required, filter replacement would not help, and you can't top off anything when the engine isn't consuming oil in the first place. And for my gas engines (granted, this is a diesel forum) the oil CAN NOT go beyond the 12k-15k range with normal service, as the TBN would be dangerously low. With severe service, the analysis indicated that 4-5k was about the limit. (UH-oh, a hole in the "never change it" theory?)

Now if you have an engine that consumes extreme quantities of oil, like a quart every 500 miles, then yep... you never really need to change it. Just keep dumping in fresh oil and and change the filter occasionally. For those of us with engines that do not burn or leak oil, that isn't an option. Also note that Edmunds, if you actually read the article, recommended following the manufacturer's change interval - which is very different than your recommendation.

You can claim victory all you want but it will be a lonely victory dance.