Diesel engines are prone to cavitation in the coolant, something to do with stresses, shock waves and harmonics. An additive is a good idea. I think that you can find information if you search for cavitation or SCA - supplemental coolant additive. I have never heard of this being a big problem on MB diesels but it is a standard precaution on many diesels. The Navistar 7.3 engines in Ford pickups often die from failures related to cavitation.

Cavitation is a strange concept. Best to think of it as a void on the inter-molecular level. Cavitations in force fields are one of the approaches to fusion reactions.