Mercedes-Benz C43 Owners Report Rattle on Cold Start

Some owners of 2019 Mercedes-Benz C43 models have reported a metallic rattle from the front-passenger area when starting the engine cold. The sound, similar to a loose heat shield, typically occurs only on cold starts and fades as the engine warms up. Restarting the car after it has warmed up usually eliminates the noise.

In many cases, the cause is a heat shield or exhaust component that contracts when cold and expands as the engine heats, silencing the rattle. This issue can also affect other European luxury models, as well as vehicles from manufacturers like BMW, Audi, Porsche, VW, Volvo, Jaguar, Lexus, Toyota, and Honda, including hybrids.

Ignoring the rattle could lead to more serious problems, such as a loose part rubbing against other components or a small crack becoming a larger repair issue. The National Highway Traffic Safety Administration (NHTSA) may have recall information or technical service bulletins related to this issue.

Owners who experience this rattle are advised to have their vehicle inspected to determine the cause and necessary repairs.