Mercedes M273 5.5/4.7L Engine Specs, Problems, Reliability. The Mercedes-Benz M273 engine household includes a 5.5-liter and 4.7-liter gasoline V8s based on M272 V6. The M273 series was launched in 2005 as a follower for the M113 engine. The new V8 was used in lots of expensive designs of the German maker in the 2000s, such as W221, x164, and w211.
The 5.5 L and 4.7 L V8s are completely aluminum engines. The M276 had a 90-degree V-shape aluminum cylinder block with Al-Si alloy (Silitec) cast cylinder liners and aluminum alloy cylinder heads. Inside an aluminum crankcase, there is a created steel crankshaft protected by strengthened bearing caps. The engine is equipped with fracture-split, forged linking rods and light-weight, low-friction aluminum pistons. The engine block of 4.7 L M273 46 KE has 92.9 mm (3.66 in) bores and an 86.0 mm (3.39 in) stroke. The 5.5-liter variation (M273 55 KE) has 98.0 mm (3.86 in) bores and a 90.5 mm (3.56 in) stroke. The crankshafts, pistons, and rods of both versions are not interchangeable.
The M273 engine likewise includes four valves per cylinder and double overhead one-piece cast camshafts (DOHC). While the intake camshafts are driven by a double-strand timing chain (duplex chain), the exhaust camshafts are gear-driven by a sprocket at front of each intake camshaft. The engine has an independent continually consumption and exhaust camshaft timing. The M273 utilizes sequential fuel injection controlled by the Bosch ME9 ECU with 2 micro-controllers. The cooling system is likewise handled by ECU – a mechanical thermostat was replaced by a brand-new digitally managed thermostat for maximum control of engine temperature level. The consumption manifold is made from an aluminum-magnesium alloy and it has tumble flaps supplying a variable length of the intake channels.
In 2010, as a replacement for the M273 engines, Daimler AG introduced the 4.6-liter V8 twin-turbocharged Mercedes-Benz M278 engine.
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Mercedes M273 Engine Problems and Reliability
Sadly, the M273 engines have earned a reputation as one of the most bothersome Mercedes V8 engines. On the Internet, there are rather a great deal of materials on the topic of M273’s common problems and failures, along with methods to fix or avoid them.
A weak location is engine timing. Engines produced in 2006 had an issue with fast used timing chain guide equipment (less than 60k miles). This failure might trigger an incorrect positioning of the camshafts. From September 2006, the manufacturer started utilizing a more difficult material for the timing chain guide gear in the production and the number of such concerns was significantly minimized.
A cam plug oil leak is another extensive issue of this engine household. This is normal for engines manufactured prior to June 2008. Oil leakage was on the backside of the cylinder heads from the round growth plugs made from plastic product. Mercedes modified those plugs in the middle of 2008 and repaired that unpleasant issue.
The consumption manifold is prone to carbon build-up inside and on the flaps utilized to vary the length of the consumption channels. Filthy flaps could be stuck or produce high loads on the plastic VIM actuator cam. In both cases, that will lead to actuator cam damage. Incorrect operation of the variable consumption manifold includes the following symptoms: rough idle and a loss of power with check engine light lighting.
Regardless of all undesirable things, in general, the M273 engine lifespan is close to 200,000 miles (300,000-320,000 km).
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Mercedes M272 3.5L Engine Specs
| Manufacturer | Daimler AG |
| Production years | 2005-2019 |
| Cylinder block material | Aluminum |
| Cylinder head material | Aluminum |
| Fuel type | Gasoline |
| Fuel system | Sequential fuel injection |
| Configuration | V |
| Number of cylinders | 8 |
| Valves per cylinder | 4 |
| Valvetrain layout | DOHC |
| Bore, mm | 92.9 mm (3.66 in) – 4.7L 98.0 mm (3.86 in) – 5.5L |
| Stroke, mm | 86.0 mm (3.39 in) – 4.7L 90.5 mm (3.56 in) – 5.5L |
| Displacement, cc | 4,663 cc (284.6 cu in) 5,461 cc (333.3 cu in) |
| Type of internal combustion engine | Four-stroke, naturally aspirated |
| Compression Ratio | 10.7:1 |
| Power, hp | 335 hp (250 kW)/6,000 – E47 382 hp (285 kW)/6,000 – E55 |
| Torque, lb ft | 339 lb-ft (460 Nm)/2,700-5,000 – E47 391 lb-ft (530 Nm)/2,800-4,800 – E55 |
| Engine weight | – |
| Firing order | 1-5-4-2-6-3-7-8 |
| Engine oil weight | MB 229.5, SAE 0W-40 |
| Engine oil capacity, liter | 8.5l (9.0 qt) |
| Oil change interval, mile | 9,000 (15,000 km) / 12 months |
| Applications | E500/E550, CL500/CL550, CLS500/CLS550, GL500/GL550, ML450/ML500/ML550, S450/S500/S550, CLK500/CLK550, GL450, G500, R500 |
