OM647

Three engines were launched together in 2002 to succeed the OM611, OM612 and OM613: a four, a five and a six sharing one set of dimensions — 88 mm bore, 88.3 mm stroke — along with cast-iron blocks, aluminum heads, chain-driven twin camshafts, four valves per cylinder, 18:1 compression, common rail to 1,600 bar and variable-geometry turbocharging. The OM647 was the 2.7-liter five. Next to the OM612 it took a new intake manifold and did without the mechanical fuel feed pump, and it made 177 PS at 4,200 rpm with 400 N·m from 1,800.

It sold as the 270 CDI, most visibly in the E-Class, and it had a short run. The EVO improvements that kept the four-cylinder OM646 alive until 2010 were never applied to the five or the six, because by then Mercedes had the OM642: a compact 72° diesel V6 short enough to fit where an inline six would not, and cheap enough to spread across the range in de-rated form. It replaced both. With the OM647 the Mercedes passenger-car diesel five, a line begun by the OM617 in 1974, came to an end.