Mercedes

Mercedes parts from 1988 to 2021: when the same 2.2 CDI receives OM611, OM646 or OM651 blocks depending on the generation

This is the most common pitfall with Mercedes: two vehicles both badged with the same 2.2 CDI do not necessarily share the same block. On the Classe C, Classe E or Sprinter, the same engine capacity has successively been fitted with the OM611, then the OM646 (with its variants 646.980, 646.982, 646.985…), then the OM651 from around 2008 onwards, each with its own power outputs and codes. A gearbox or engine from one of these families cannot be substituted for another: checking the code stamped on the original part is essential before placing any order.

Turbos, gearboxes, engines: the range spread across 26 models

The range covers 26 Mercedes models, from the Sprinter and the Vito to the Classe C, E, A and B, as well as the CLA, GLC, GLA, ML, CLS and the Citan. Turbos make up the largest family, followed by gearboxes — 5- and 6-speed manuals —, bare engines and a transfer case. On the diesel side, the OM642 V6 3.0 CDI is fitted to the top-of-the-range models (Classe E, CLS, ML, GLC) with codes 642.826, 642.873, 642.890, 642.940 or 642.961 depending on the variant. The Citan and certain Classe A models are fitted with the 1.5 CDI OM607, derived from the Renault K9K base, which makes identification by engine code even more critical. On the petrol side, the M270 engines (1.6 and 1.5) and M276 (3.0 V6 biturbo, codes M276.820 and M276.823) cover very different applications, from the Classe B 160 to the GLC 43 AMG or the E 400.

Key points for Mercedes identification

The 3.0 CDI V6 OM642 is found on vehicles as varied as the Sprinter, the ML and the Classe E: the sub-reference (642.826, 642.890, 642.940, 642.993…) varies according to torque output, emissions standard and whether four-wheel drive is fitted. On the M270 petrol blocks, codes M270.910 and M270.920 distinguish between different power levels — the former covers the 160 and 180, the latter the 220 and 250 — without the stated engine capacity giving any indication of this. For reconditioned or exchange versions, the full engine code remains the only reliable identifier. The parts cover the period 1988–2021, which includes older blocks such as the OM601 or OM602 (2.9 D, 2.9 CDI) for commercial vehicles from the 1990s, through to the OM654 units found in recent 220 d models.