I'm not sure what you mean? Soot is a byproduct of combustion, the way I understand it soot is made up of small abrasive particals. Different engines make more soot, the older diesels like the 616 and 617 for example make a lot more soot then say a 606 or a CDI. But every engine is different and driving habits and conditions affect soot loading. MB says don't go over 2%. If you want to extend your drain intervils get a sample tested at say 5k miles, the report will point out wear metals, additives, soot ect. This way you can tell how far you can extend your drain intervils.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200