M21

1983–1991•6 cyl•Inline•Al / cast_iron

Successor: M51 →

• First BMW diesel engine • Timing belt • High torque at low rpm

The BMW M21 is the first diesel engine by BMW (1983–1991). Turbocharged inline-6, used in E28 524td, E30 324td, E34 524td. Cast iron block, aluminium SOHC head, timing belt. Displacement 2.4 L, power 84–115 hp. Good torque (152–220 Nm). Simple and reliable, but requires regular timing belt replacement and valve clearance adjustment. Paved the way for future BMW diesels. Capable of over 350,000 km with proper maintenance.