13Z Diesel Engine Toyota 13Z is a 4.6-liter in-line 6-cylinder diesel engine. It has been specifically designed for use in industrial vehicles and features a uniquely shaped combustion chamber and a direct-injection fuel system. The 13Z provides high output while reducing exhaust smoke emissions. The full-floating engine mount design and large muffler help to reduce Professional values-4 (100% Elimination of Diesel Smoke)