| Mercedes-Benz M272 | |
| Manufacturer: | Mercedes-Benz |
| Production: | 2004–2017 |
| Configuration: | Naturally aspirated 90° V6 |
| Block: | Aluminum |
| Head: | Aluminum |
| Successor: | Mercedes-Benz M276 |
| Valvetrain: | DOHC 4 valves x cyl. with continuous VVT |
| Fueltype: | Gasoline or E85 (M272 929) |
| Fuelsystem: | port injection or direct injection (CGI) |
| Coolingsystem: | Water cooled |
| Displacement: | 2496cc 2996cc 3498cc |
| Bore: | 88mm 92.9mm |
| Stroke: | 68.4mm 82mm 86mm |
| Power: | NaN0NaN0 |
| Torque: | NaN0NaN0 |
| Predecessor: | Mercedes-Benz M112 |
The Mercedes-Benz M272 engine is an automobile piston V6 engine family used in the 2000s (decade). Introduced in 2004, it is based on the M112 V6 introduced in 1998.
All M272 engines have aluminum engine blocks with a 90° V-angle with silicon/aluminum lined cylinders. The aluminum DOHC cylinder heads have 4 valves per cylinder. All have forged steel connecting rods, one-piece cast crankshaft, iron-coated aluminum pistons and a magnesium intake manifold. Like the M112, a balance shaft is installed in the engine block between the cylinder banks to deal with vibrations in the 90 degree V6 design. This essentially eliminates first and second order moments. A dual-length Variable Length Intake Manifold is fitted to optimize engine flexibility.
Continuous VVT was adopted for the first time. Featured on both the intake and exhaust camshafts, each can be varied through a range of 40 degrees. The twin spark plug system was replaced by a regular single spark plug per cylinder. New electronic coolant flow control has replaced the mechanical thermostat for improved engine warm-up and optimum control of engine temperature. Also tumble flaps are used to improve output at low engine speeds.
The E25 is a 2496cc version. Bore and stroke dimension is NaNmm. Output is 2040NaN0 at 6100 rpm with 2450NaN0 of torque at 2900-5500 rpm.
Applications:
The E30 is a 2996cc version. Bore and stroke is NaNmm. Output is 2310NaN0 at 6000 rpm with 3000NaN0 of torque at 2500-5000 rpm.
Applications:
The E35 is a 3498cc version. Bore and stroke dimension is NaNmm. Output is 2720NaN0 at 6000 rpm with 3500NaN0 of torque at 3500 rpm. A direct injected variant debuted in 2006 under the name Stratified-Charged Gasoline Injection (CGI). First fitted to the CLS350 CGI, it produces 2920NaN0 and 3650NaN0 of torque while lowering fuel consumption. In 2008, the non-CGI engine was uprated to 3160NaN0 at 6500 rpm and 3600NaN0 of torque at 4900 rpm with 350Nm being delivered at 2000rpm. This was achieved by raising the rev-limit to 7200 rpm, increasing the compression ratio using enhanced, weight-optimized pistons with a curved surface, reinforcements in the area of the piston pins, deeper pockets for the valve seats, single-stage intake manifold, lightweight valves with sodium cooling, conical valve springs, tri-oval chain sprocket, and a new cylinder head.
Applications:
M272 engines that were sold between 2004[1] [2] and 2008 with engine serial numbers below 2729..30 468993 often show early wear of the balance shaft gears, requiring extensive repairs at a retail cost of over $4,000.[3] [4] These complaints led to a class action lawsuit against Mercedes-Benz (Greg Suddreth and Paul Dunton v. Mercedes-Benz USA, LLC), which alleged the M272 engines are equipped with defective balance shafts gears which "wear out prematurely, excessively and without warning, purportedly causing the vehicles to malfunction, the check engine light to illuminate and the vehicle to misfire and/or stop driving."[5] The suit further alleged that Mercedes knew of this problem, sending out repair bulletins on how to address this issue and ultimately changing the balance shaft gears to avoid this problem. This suit was ultimately dismissed with the judge agreeing with Mercedes that because the gears fail at 60 -80K miles and outside of the warranty period, Mercedes is not legally responsible for these problems.[6]
However, a second class action lawsuit was filed in October 2012 in Northern California,[7] covering Mercedes-Benz models manufactured between 2005 and 2007. A preliminary settlement was reached on April 8, 2015,[8] which would see owners compensated for up to 70% of the cost of the repair.
These engines also have a common issue with their intake manifolds. The M273 also has similar issues but not to the same extent. The plastic lever that operates the opening and closing of the variable length intake manifold can break prematurely. Mercedes doesn't have this particular part listed, instead they sell the whole intake manifold as one unit which can cost upwards of $800 US. There are a number of third-party companies that sell a replacement lever made out of metal at a much cheaper cost.