The Mercedes-Benz M273 engine is a V8 automobile piston engine family used in the 2000s (decade). It was based on the similar M272 V6 introduced in 2004.

An evolution of the M113 V8,^[1] all M273s have aluminium engine blocks, sequential port fuel injection, fracture-split forged steel connecting rods, a one-piece cast crankshaft, and a magnesium intake manifold. The cylinders are lined with silicon/aluminium, and a dual-length variable-length intake manifold is fitted.^[2]

In addition to this, new features shared with the M272 include DOHC aluminium cylinder heads, 4 valves per cylinder and independent continuously variable valve timing on both the intake and exhaust sides. A new electronically controlled cooling system has eliminated the need for a mechanical thermostat for improved engine warm-up and optimum control of engine temperature.

The E47 is a 4.7 L (4,663 cc) version. Bore and stroke is 92.9 mm × 86 mm (3.66 in × 3.39 in). Output is 250 kW (340 PS; 335 hp) at 6000 rpm with 460 N⋅m (339 lb⋅ft) of torque at 2700–5000 rpm.

Applications:

• 2007–2012 GL 450 (X164)
• 2007–2013 S 450 (W221)

The E55 is a 5.5 L (5,461 cc) version. Bore and stroke increased to 98 mm × 90.5 mm (3.86 in × 3.56 in). Output is 285 kW (387 PS; 382 hp) at 6000 rpm with 530 N⋅m (391 lb⋅ft) of torque at 2800–4800 rpm.

Applications:

• 2006–2009 E 500 / E 550 (W211)
• 2009–2011 E 500 / E 550 (W212)
• 2006–2010 CL 500 / CL 550 (C216)
• 2006–2010 CLS 500 / CLS 550 (C219)
• 2006–2012 GL 500 / GL 550 (X164)
• 2008–2011 ML 500 / ML 550 (W164)
• 2005–2011 S 500 / S 550 (W221)
• 2006–2012 SL 500 / SL 550 (R230)
• 2006–2009 CLK 500 / CLK 550 (C209)
• 2006–2015 G 500 / G 550 (W463)
• 2007–2014 R 500 / R 550 (W251)
• 2010–present KSU Gazal-1

*Note: 500 or 550 model naming varies depending on geographical market.

• Mercedes-Benz M152 engine and Mercedes-Benz M156 engine for AMG offerings for the similar generation
• List of Mercedes-Benz engines