Reconditioned BMW Engine

BMW petrol and diesel engines: two distinct engine families, two separate sets of codes

The range covered here spans 1999 to 2024 and brings together eleven models — Série 1, Série 2, Série 3, Série 4, Série 5, X1, X2, X3, X4, X5, X6 — with 71 reconditioned bare engines split between two clearly distinct families: the petrol units (1.5i, 1.6i, 1.9i, 2.0i, 2.5i, 3.0i) and the diesel units (1.5d, 2.0d, 3.0d). These two families share no architecture, no engine codes and no common parts. Confusing a B47 with a B48 because the engine capacities are similar is the most common identification mistake.

The diesel family — 2.0d and 3.0d: generations M47, N47, M57, N57, B47

This is where the greatest care is needed. The 2.0d has gone through several generations of codes: M47D20, N47D20A/B/C/D, B47C20A/B, B47D20B. These codes are not interchangeable — the N47 generation (timing chain on the flywheel side, a well-documented weak point) is structurally different from the B47 that replaced it. The 3.0d follows the same pattern of succession: M57D30, N57D30A/B/C cover very different power outputs and configurations, from the standard 3.0d to the 335d Biturbo (N57D30B) and the M50d (N57D30C). For the X5, X3 and Série 5 in xDrive, the engine suffix (xDrive30d, M50d) is an indicator of the engine code, not just of power output.

Petrol: from the three-cylinder B38 to the six-cylinder N55 — engines with no diesel equivalent

The 1.5i 3-cylinder (B38A15A, B38B15A) is fitted mainly to recent entry-level Série 1, Série 2 and X1 models. The 2.0i covers the codes N20B20A/B/D, N43B20A, B48A20A — four distinct codes for the same engine capacity, depending on the generation and model. The 3.0i 6-cylinder in-line (N55B30A) relates primarily to the sporting versions of the Série 3 and Série 5. The 1.6i (N13B16A, N45B16A) and the 1.9i (M43B19) are older engines, found on Série 1 and Série 3 models from the earliest generations covered (from 1999 onwards). In every case, the code stamped on the block is the definitive reference: a single suffix error (A vs B, C vs D) is enough to make the engine incompatible.