NHTSA Defect Petition DP22002

In a letter dated April 29, 2022, Mr. Sergio Betancourt (the petitioner) submitted a petition attributing engine failure of his 2015 Mercedes-Benz C300 to “wrong sized wrist-pins” and asserted that these were prevalent on all Mercedes-Benz models (including the Metris minivan, GLC300, and C300) equipped with a version of the M274 engine. The petition cited Mercedes Technical Service Bulletin (TSB) LI03.10-P-060916 (meant for the 2015 C300) and postulated that the “wrong-sized wrist pin” would allow the piston to “wiggle in the cylinder as it would move up and down”. In addition to the Mercedes-Benz TSB, the petitioner enclosed a service center repair estimate and images of other online submissions discussing the M274 engine. In the incident that prompted the petition, the petitioner reported that the vehicle lost power and shook in response to accelerator application during highway driving, followed by white smoke from the exhaust pipe. The petitioner stated that the subsequent service center visit led to a cracked piston diagnosis. The service record from this visit prescribed an engine teardown to localize the failure and characterize any resulting engine damage and listed a number of repair options that included replacement of one piston, four pistons, or the entire engine long block (depending on the level of damage suffered). TSB LI03.10-P-060916 (“TSB”) was first released on February 27, 2015 and pertained to Engine Code 274.920. It cited the following complaint condition: “Clattering/rattling or knocking noise from the crank assembly of the engine when cold at oil temperatures up to approximately 50°C mostly heard on engine deceleration” and listed the cause as under analysis. The TSB gave further instructions on the collection of information and discouraged the replacement of any components. On September 21, 2015, TSB Version 4 introduced engine build clean points (March 27, 2015 or April 20, 2015 depending on the engine plant); cause: unfavorable tolerance