While CH-4 IS the highest current rating for diesel engine lubricating oil, it isn't necessarily the appropriate oil for the older engines. There is nothing wrong with using it, but there is also nothing wrong with using Mobil 1 with it's CF rating. In fact, there are certain advantages...
The benefits of synthetic oil aren't just better lubrication at high temperatures, and easier flow when starting at cold temperatures. There are many more, and not the least of them are: increased fuel economy, no wax or paraffin build up, better detergency, almost no formation of acids from the condensation formed during the combustion process, and better overall lubrication.
I truly believe that the Mercedes Benz passenger car diesel engine with indirect injection will work to it's optimum performance and best longevity with a combination of proper maintenance, high cetane rated fuel and additive, regular oil & filter changes, and the use of a synthetic motor oil with a rating of CF.
The chart at the API website is the best determining factor for choosing motor oil for your passenger car diesel.
http://www.api.org/programs_services/quality/oilchart.htm
Mercedes Benz passenger car diesel engines are about as related to a CAT diesel in a commercial vehicle as a Palomino is to a Zebra.
And if I were still running trucks with CAT and Big Block Cummins engines across North America like I used to, I'd be using Mobil DelVac 1 right now...