The Mercedes-Benz M272 was a V6 petrol engine that was first introduced in 2004 to replace the M112 engine. Developed in conjunction with the M273 V8 petrol engine, the M272 engine’s cylinder banks were at a 90 degree angle from each other. As a result, a balance shaft was installed in the engine block between the cylinder banks to reduce first and second order inertial forces.
The M272 engine had a light alloy block with cast Al-Si alloy cylinder liners and a cast iron crankshaft bearing cap bolted to the side of the block, an aluminium cylinder head, forged steel connecting rods, a one-piece cast crankshaft, iron-coated aluminium pistons, a magnesium intake manifold, double overhead camshafts per cylinder bank (chain-driven), independent and continuous adjustment of the intake and exhaust camshafts (over a range of 40 degrees), four valves per cylinder actuated by roller cam followers, a centrally-located spark plug for each cylinder and a variable length intake manifold.
The M272 initially had conventional, manifold fuel injection. From 2005, the engine was available with direct fuel injection for the C219 CLS 350 CGI, while the W212 and S212 E-Class followed in 2007.
The M272 engine was superseded by the M276 engine in 2011.
| Engine | Bore/Stroke | Capacity | C.R. | Peak power | Peak torque |
|---|---|---|---|---|---|
| M272 KE 25 | 88.0 x 68.4 | 2496 cc | 11.2:1 | 150 kW at 6200 rpm | 245 Nm at 2900-5500 rpm |
| M272 KE 30 | 88.0 x 82.1 | 2996 cc | 11.3:1 | 170 kW at 6000 rpm | 300 Nm at 2500-5000 rpm |
| M272 KE 35 | 92.9 x 86.0 | 3498 cc | 10.7:1 | 190 kW at 6000 rpm | 340 Nm at 2500-5000 rpm |
| M272 KE 35 | 92.9 x 86.0 | 3498 cc | 10.7:1 | 200 kW at 6000 rpm | 350 Nm at 2400-5000 rpm |
| M272 KE 35 (CGI) | 92.9 x 86.0 | 3498 cc | 12.2:1 | 215 kW at 6400 rpm | 365 Nm at 3000-5100 rpm |
| M272 KE 35 Sport Motor (R171) | 92.9 x 86.0 | 3498 cc | 11.7:1 | 224 kW at 6500 rpm | 360 Nm at 4900 rpm |
| M272 KE 35 Sport Motor (R230) | 92.9 x 86.0 | 3498 cc | 10.5:1 | 232 kW at 6500 rpm | 360 Nm at 4900 rpm |
M272 engine: balancer shaft sprocket gear failure
In May 2011, Mercedes-Benz issued service bulletin LI03.30-P-050027 for Mercedes-Benz vehicles with M272 V6 engines which:
- Had serial numbers prior to 2729..30 468993; and,
- Were manufactured prior to October 2006.
In these vehicles, premature wear of a gear on the balancer shaft sprocket could cause the positioning of the camshafts in the right cylinder bank to be impaired (relative to the crankshaft). According to the service bulletin, this wear of the balancer shaft sprocket could cause the following symptoms:
- Illumination of the check engine light; and,
- Diagnostic trouble codes (DTCs) 1200 or 1208 stored in the ME-SFI control unit.
Owners have experienced failure of the balancer shaft sprocket gear after 95,000 kilometres, accompanied by rough running and illumination of the check engine light. From October 2006 production, a different material was used for the balance shaft sprocket.
For the M272 V6 engine, the repair procedure is as follows:
- Remove the right front camshaft adjuster cover;
- Check the balance shaft sprocket for wear using a flexible borescope. In rare cases, a stretched timing chain may be the reason for the DTCs if the sprocket does not exhibit any signs of wear;
- If worn, replace the balance shaft. Note: since the balancer shaft is located inside the engine block, repairs are expensive;
- Replace the chain tensioner (part number A272 050 01 11);
- Change engine oil and filter;
- Drive with engine at high load and rpm for at least 20 km;
- Change engine oil and filter once more; and,
- Replace the camshaft adjustment solenoids.
M272 engine: cam plug oil leak
Mercedes-Benz M272 V6 and M273 V8 engines that were produced prior to June 2008 may experience oil leaks (or ‘seepage’) from the round plastic expansion plugs (‘cam plugs’) on the back of the cylinder heads. There were two different size cam plugs:
- Part number A000 998 55 90: two small expansion plugs (approximately 2.5 cm diameter); and,
- Part number A000 998 56 90: one large small expansion plug (for engines without vacuum pump).
To fix, the existing plugs were to be removed, the opening cleaned and new plugs fitted; no sealer was to be used in the installation of the new plugs. In June 2008, new cam plugs that were not susceptible to oil leaks were phased into production.
M272 V6 and M273 V8 engines: VIM actuator cam breakage
For Mercedes-Benz M272 and M273 V8 engines, the plastic actuator cam in the variable intake manifold (VIM) is susceptible to failure. Symptoms of a broken actuator cam include:
- Rough idle;
- A loss of power (particularly at low and mid-range engine speeds);
- Illumination of the check engine lights; and,
- Diagnostic Trouble Codes (DTCs) such as P2004, P2005, P2006, P2187 and P2189.
Due to the venting of oil from the PCV (positive crankcase ventilation) system, carbon deposits can accumulate on the swirl flaps inside the variable intake manifold. These carbon deposits increase the resistance on the plastic actuator cam and this can cause it to break. Other parts can also fail as a result, including the swirl flaps, the actuator mounting arms and the vacuum diaphragms.
AustralianCar.Reviews understands that the original equipment supplier for the intake manifold is Pierberg and that Mercedes-Benz’s repair involves replacing the entire intake manifold since they do not supply replacement actuator cams. However, eEuroparts.com sell intake manifold repair kits that replace the plastic actuator cam with a metal component and can be used for DIY repairs. However, the intake manifold also needs to be cleaned as part of any repair. For further information about this problem, please see:
- eEuroparts.com: Fixing Mercedes-Benz Intake Manifold Woes; and,
- eEuroparts.com: Mercedes-Benz Intake Manifold Repair DIY.
