N40

The BMW N40 is an inline four-cylinder petrol engine produced from 2001 to 2006. It was a simplified version of the N42 without Valvetronic, intended for entry-level E46 and E85 models. The engine had an aluminium block with cast-iron liners, an aluminium DOHC head, and a timing chain. Displacement 1.6 or 1.8 litres, power up to 115 hp. It was simple and relatively fuel-efficient. Common issues include timing chain wear, VANOS problems (where equipped), and oil leaks. With proper care, the N40 can exceed 200,000 km.