Mercedes-AMG’s high-performance C63 sedan appears to be heading toward yet another major transformation, as new reports suggest it will transition from a four-cylinder plug-in hybrid setup to a more powerful six-cylinder engine. This potential change comes after widespread criticism and lukewarm market response to the brand’s previous decision to downsize from a V8 to a four-cylinder hybrid drivetrain. Although rumors of a return to the V8 engine have circulated for years, the latest information points to a 3.0-litre inline six-cylinder engine taking center stage in future models.
The details vary slightly depending on the source. Germany’s Mercedes-Benz Passion Blog, a publication with a track record of insider information, recently claimed that both the AMG C63 and C43 will be discontinued in 2026 during the C-Class sedan’s mid-cycle facelift. In their place, a new model — the C53 — is expected to launch. According to the report, this new version will use the same six-cylinder engine found in the CLE53, paired with mild-hybrid technology. This change is reportedly prompted by sluggish sales performance of the current four-cylinder variants, especially in key markets like Australia, where the BMW M3 Competition has outsold the C63 by nearly 50%.
The proposed engine, which currently produces 330kW and 560Nm of torque (rising to 600Nm on overboost in the CLE53), could undergo further tuning for the C-Class. However, Passion Blog asserts that the plug-in hybrid system used in the outgoing C63 is unlikely to carry over, hinting at a shift toward a simpler mild-hybrid configuration.
In contrast, a report from the UK’s Autocar paints a slightly different picture. According to their sources, the C63 nameplate will continue, and the upcoming model will combine the new six-cylinder engine with plug-in hybrid assistance. This setup is expected to deliver 480 hp from the petrol engine alone, and a total output of 650 hp when the electric motor is factored in. Unlike the outgoing model, which uses a rear-mounted electric motor, the revised C63 will reportedly adopt a more traditional hybrid layout, placing the motor between the engine and transmission.
Despite persistent rumors, both publications agree on one thing: the 4.0-litre twin-turbo V8 is not returning to the C-Class. Autocar explains that the current C-Class platform was designed exclusively for four-cylinder engines, leaving no room for a V8 due to space constraints, cooling requirements, and crash safety standards.
Looking ahead, the facelifted C63 is also expected to receive interior upgrades, including the introduction of Mercedes-Benz’s Superscreen display and updated infotainment software. With Mercedes-AMG acknowledging that its bold move to downsize has cost them in terms of sales, the upcoming shift to six-cylinder power is likely an effort to strike a balance between performance, innovation, and customer expectations — potentially positioning the C-Class AMG more competitively against its long-standing rival, the BMW M3.