This document provides instructions for servicing and maintaining the engine of a Doosan DX490LC-5/DX530LC-5 excavator. It begins with safety instructions and an overview of the engine components. The bulk of the document provides detailed instructions for various maintenance and repair tasks for the engine, including removing and installing various engine parts like the cylinder head, fuel injectors, intake and exhaust manifolds, valve train components, and more. Precautions are given to mark parts during disassembly and carefully reinstall them.