This manual pertains to the Volvo AQ151, an inline 4-cylinder engine with a displacement of 2.5 liters (2499cc). While specific production years are not detailed, this factory service repair manual covers a range of models. The AQ151 is known for its robust engineering and reliability, often found in marine applications, and typically rated around 152 horsepower. Its design emphasizes performance and durability for demanding operational environments. The purpose of this comprehensive English-language service manual is to provide detailed guidance for the maintenance, repair, and technical understanding of the Volvo AQ151 engine. It encompasses essential information on engine specifications, recommended service procedures, fluid requirements, and intervals. Owners, technicians, and mechanics will find the extensive coverage invaluable for ensuring the optimal performance and longevity of their AQ151 engine.