Mercedes-Benz M156 Engine Class Action Lawsuit

Mercedes-Benz M156 Engine Class Action

The Mercedes-Benz M156 engine class action is a 2011 consumer product case in which owners of certain Mercedes-AMG vehicles alleged that the M156 V8 engine installed in their cars suffered a known design flaw that caused premature wear of engine components. The suit was filed in the United States District Court for the District of New Jersey against Daimler AG, Mercedes-Benz, and Mercedes-AMG. The court dismissed the plaintiffs' first amended complaint for lack of standing in November 2012, and the matter is recorded as a dismissal resolving in 2012.

Product and manufacturer

The M156 is a 6.2-liter naturally aspirated V8 engine built by Mercedes-AMG, the high-performance subsidiary of Mercedes-Benz. It was the first AMG engine developed autonomously by AMG rather than adapted from a standard Mercedes-Benz design, with a block and bore spacing of its own. The unit powered a wide range of AMG-badged Mercedes-Benz models, including the C 63, CLK 63, CLS 63, CL 63, S 63, SL 63, ML 63, and R 63 AMG, from the late 2000s into the 2010s. Output varied by model, ranging from roughly 450 to more than 500 horsepower depending on the application, and the engine is marketed under the "6.3" designation in reference to Mercedes' first production V8.

The alleged defect and the harm

Owners of AMG vehicles from the 2007 through 2011 model years reported that the M156's valvetrain wore out earlier than expected, with symptoms such as ticking noises at cold start and accelerated wear of lifters, camshafts, and camshaft adjusters. The class action alleged that the premature wear was driven by the combination of cast nodular iron camshafts and 9310-grade steel valve lifters, and that the defendants had known about the problem since 2007. Separately from the litigation, owner discussions of the M156 also mention other recurring issues on these engines, including deterioration of the crankcase breather valve diaphragm, cracking of the breather hose, excess oil consumption, intake manifold failures, and head bolt concerns on 2007–2011 models.

Litigation

The class action was filed in 2011 in the United States District Court for the District of New Jersey. It named Daimler AG, Mercedes-Benz, and Mercedes-AMG as defendants and sought to represent owners of affected AMG vehicles who claimed the engine defect reduced the value of their cars and caused avoidable repair exposure. The defendants answered the complaint, and the parties litigated the case through amendments and motion practice in the district court.

Outcome

In November 2012, the court dismissed the plaintiffs' first amended complaint for lack of standing. The plaintiffs were given the opportunity to amend their complaint to cure the standing defect, but they made no further filings with the court. Following that, the court signed an order closing the case. No further resolution is documented for this matter; it is archived as a case that ended in dismissal in 2012, without a trial or a jury determination on the merits.

No primary sources are listed in the case record for this entry; the page is based on the article below.