The Mercedes-BenzM272 engine is an automobilepistonV6 engine family used in the 2000s. 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 DOHCcylinder heads have 4 valves per cylinder. Direct injection is used in a limited fashion on the 3.5 L V6, whereas others use conventional port fuel injection. All have forged steelconnecting 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.
E25
The E25 is a version. Bore and stroke dimension is. Output is at 6100 rpm with of torque at 2900-5500 rpm. Applications:
The E35 is a version. Bore and stroke dimension is. Output is at 6000 rpm with of torque at 3500 rpm. A direct injected variant debuted in 2006 under the name Stratified-Charged Gasoline Injection. First fitted to the CLS350 CGI, it produces and of torque while lowering fuel consumption. In 2008, the non-CGI engine was uprated to at 6500 rpm and of torque at 4900 rpm. This was achieved by raising the rev-limit to 7200 rpm, increasing the compression ratio and other modifications to the valvetrain. Applications:
M272 engines that were sold between 2004 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 $4000. These complaints led to a class action lawsuit against Mercedes-Benz, 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." 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. However, a second class action lawsuit was filed in October 2012 in Northern California, covering Mercedes-Benz models manufactured between 2005 and 2007. A preliminary settlement was reached on April 8, 2015, which would see owners compensated for up to 70% of the cost of the repair. The settlement terms are expected to be ratified in August 2015. 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.
