Chilton's repair & tune-up guide, Mercedes-Benz, 1974-79: Gasoline & diesel models, 230, 240D, 280, 280C, 280E, 280CE, 280S, 280SE, 300D, 300CD, 300SD, 300TD, 450SE, 450SEL, 450SEL 6.9, 450SL, 450SLC