MILAN — Sergio Marchionne, who engineered two long-shot corporate turnarounds to save carmakers Fiat and Chrysler from failure, died Wednesday. He was 66.

The holding company of Fiat’s founders, the Agnelli family, announced Marchionne died after unexpected complications from surgery in Zurich. That came days after a deterioration in his health led the company to hastily appoint a successor as CEO.