M67

The BMW M67 is a turbocharged V8 diesel engine produced from 1998 to 2008. It powered flagship models like the E38 740d, E65/E66 745d, and E53 X5. The engine had a cast iron 90° V8 block, aluminium DOHC heads, and timing chains. Displacement 3.9 or 4.4 litres, power up to 300 hp (M67D44), torque up to 700 Nm. It featured Bosch Common Rail injection (up to 1800 bar) and variable geometry turbochargers on later versions.

The engine was noted for its massive torque, smoothness, and low noise. Weak points include piezo injectors (later versions), turbochargers, DPF, and occasional timing chain issues. With proper maintenance, the M67 can exceed 300,000 km without major overhaul.

The TU variant bumped the power and torque from the original 1999 version (which had 238 hp and 413 lb-ft) through refined ECU mapping, upgraded injectors, and improved turbo management.