Reconditioned BMW Engine

B-series petrol engines and N47 / N57 diesels: two distinct engine families at BMW

The BMW catalogue here covers eleven models — from the 1 Series to the X6 — spanning 1999 to 2024, with two clearly separate families that should not be confused. On the petrol side, the key distinction is between the older N (N13B16A, N20B20A, N52B25A, N55B30A) and the current generations B (B38B15A, B38A15A, B47C20A, B48A20A): architecture, sump, mountings and ancillaries differ significantly, even at the same engine capacity. On the diesel side, the same logic applies between the M47 / M57 first-generation units and the N47 / N57, which notably introduce a timing chain on the gearbox side — a well-documented weak point, particularly on the N47D20.

N47, N57 and B47: three 2.0d or 3.0d diesels that share very little

On the 2.0d, three engine codes exist depending on the year and power output: N47D20A, N47D20B, N47D20C and N47D20D for the N47 generation, then B47C20A and B47D20B for the B generation. These units are not mechanically interchangeable, even when fitted to the same 3 Series or X1. On the 3.0d, the distinction concerns the naturally aspirated or twin-turbo version: the M57D30 (306D2 or 306D3), the N57D30A and the N57D30B / N57D30C (M50d, 335d Biturbo) meet very different specifications. The engine code stamped on the block remains the only reliable way to identify the exact reference.

Petrol 1.5i, 2.0i, 3.0i: from the B38 modular architecture to the N55 six-cylinder

The three-cylinder B38B15A (1.5i) is fitted primarily to the 1 Series, 2 Series and X1 from 2014 onwards. The 2.0i comes in N20B20A, N20B20B, N20B20D and B48A20A — four distinct engine codes depending on the generation and power output. The six-cylinder N55B30A (3.0i turbo) is found in the 3 Series, 4 Series, X3 and X5, with a specific mechanical configuration not to be confused with the naturally aspirated N52B25A. All these engines are available as a reconditioned bare engine, on an exchange basis, or as a rebuild of your own unit depending on the reference — with no ancillaries included (turbo, alternator, starter motor).