If you're considering buying a BMW with a 2.0-liter diesel engine, you'll most likely be choosing between the N47 and the B47. While both engines are known for their strong fuel economy and solid performance, there are several key differences that can significantly impact long-term reliability and ownership costs.

Reliability

Reliability is where these two engines differ the most.

Produced between 2007 and 2014, the BMW N47 earned a reputation for its timing chain issues. Because the chain is located at the rear of the engine, replacing it is both labor-intensive and expensive. Although BMW introduced improvements in later production years, early N47 engines—particularly those built before 2011—remain the most prone to timing chain failures.

The BMW B47, introduced in 2014, was designed to address these shortcomings. It features a redesigned timing chain system that is significantly more durable, making it one of BMW's most dependable modern four-cylinder diesel engines. While the B47 can still experience issues related to components such as the EGR valve or diesel particulate filter (DPF), these are generally less severe and far less costly than a timing chain failure.

Performance

The B47 also delivers a slight performance advantage. In the BMW 320d, it typically produces 190 hp and 400 Nm of torque, compared with 184 hp and 380 Nm from the equivalent N47 version. While the difference isn't dramatic, the B47 feels smoother, quieter, and more responsive in everyday driving thanks to improved engine management and reduced turbo lag.

Fuel Economy

Both engines are impressively fuel-efficient, but the B47 benefits from newer fuel injection technology and improved combustion efficiency. As a result, it typically delivers 5–10% better fuel economy under similar driving conditions, making it the more economical choice over the long term.