My son used to drive a company truck, '05 Columbia with the MB450 Mercedes motor. Rotted a piston away with something like 460k miles on it. They think the coolant hadn't been tended to properly causing cavitation or something. What little I know about these big trucks the coolant thing is complicated. There are all sorts of coolants and additives and filters and such. I decided to let the dealer that services my truck handle that part.
'03 Freightliner FL112, 295" wheel base, with '03 United Specialties 26' living quarters, single screw, Cat C12 430 h/p 1650 torque, Eaton 10speed , 3.42 rear axle ratio