On a diesel, decarbonization, just like most other things about a diesel as compared to a gas engine, is a totally different situation.

To start with, technically there is no such thing as "carbon" in a diesel. Diesel fuel is basically a light oil. The byproduct of combustion in a diesel is soot rather than carbon as in a diesel engine. One reason a diesel lasts longer is that this soot is not a mild abrasive, as is carbon.

Secondly, when using additives, you are only putting these additives through the injection pump, injectors, combustion chambers and exhaust. Many gas engines with injection are similar, but the additive also flows over the intake valve, which is where much of the carbonization degrades air/fuel flow capability.

In many MB diesels, especially in their twilight miles, build up a black goo in the intake manifold. Since only air flows through the intake manifold, the additive will do very little, if anything to remedy this problem.

The only remedy that I know of is removal and cleaning of the intake manifold. Cleaning the manifold is a slow, nasty job. You might take it to an automotive machine shop for cleaning in their jet wash, or if they have a vat of some sort that is usable on aluminum parts, that may be an alternative.

Hope this information is useful.

Have a great day,