I'm still convinced that 1 or 2 of idle time will not hurt anything, If you keep your oil changed. I'm a little weak on MB motors however, have worked with Farm diesel for years. I know engine which are left to run will operate for many hours with out any engine work. A engine that is started and stopped will require starter mx, shorter life before blow by develops. After it's kind of fun cleaning that soot out on the open road. (my faviorte is to load up at the drive-thru