This manual covers the Navistar International VT 365 diesel engine, a robust powerplant designed for demanding applications in trucks, industrial equipment, and heavy equipment. Featuring a 5.7-liter (349 cubic inch) displacement, this engine utilizes a High-Pressure Common Rail fuel system and an Electronically Controlled Variable Geometry Turbocharger (VGT) for efficient operation. Its engineering emphasizes reliability and performance, incorporating components such as an oil cooler, Gerotor oil pump, and an EGR system to meet emission standards. This comprehensive Service Repair and Diagnostic/Troubleshooting Manual, presented in English, provides essential information for maintaining and repairing the VT 365 engine. With 1254 pages, it details service diagnosis, troubleshooting for various engine symptoms and starting issues, performance diagnostics, and electronic control systems. The manual includes appendices for special service tools and diagnostic trouble codes, offering detailed guidance on structural components like the crankcase, cylinder head, front and rear covers, and valve train.