This workshop service manual covers the Volvo B21 engine, an Inline-4 unit with a displacement of 2.1 liters (2100cc). Known for its robust engineering, the B21 features a SOHC valvetrain and typically utilizes a distributor ignition system. Fuel delivery can be via carburetor or fuel injection, depending on the specific variant. Transmission options include manual gearboxes with 4 or 5 speeds, or automatic transmissions with 3 speeds. Power output varies by variant, generally ranging from 90 to 125 horsepower. This comprehensive English-language manual is designed for professional technicians and provides detailed information essential for the maintenance and repair of the Volvo B21 engine. It includes procedures for lubrication, detailing oil capacity and recommended grades, as well as information on the cooling system, timing system, and spark plugs. Technical specifications and troubleshooting guidance are also covered, enabling users to ensure optimal performance and longevity of the vehicle.