Mercedes-AMG is set to bring a new 6-cyl. performance model to its lineup as part of measures included in a midcycle facelift planned for the fifth-generation C-Class in 2026.
The move comes as Mercedes-Benz’s performance-car division prepares a retreat from its 4-cyl. plug-in hybrid system introduced in 2022. Currently powering the C63 4Matic, it combines an electrically turbocharged 2.0L gasoline engine and a rear-axle-mounted electric motor to develop a combined 670 hp and 752 lb.-ft. (1,019 Nm) of torque.
Despite being the most powerful C-Class model to date, sales of the existing 4-cyl. C63 have lagged well behind expectations in all of Mercedes-AMG’s key global markets – including North America, forcing a rethink of its previous propulsion strategy.
In the facelifted C-Class lineup, the current 4-cyl. will be replaced by a new turbocharged 3.0L 6-cyl. in a successor to the C63 4Matic, likely taking the C53 name into production. The new powertrain will ditch the “P3” rear-axle-motor layout in favor of a “P2” location with the electric motor placed between the engine and gearbox. The new model will continue to be a PHEV.
The new setup marks the latest development of a system used in various AMG models, including the E53 4Matic, GLE53 4Matic and more recently introduced CLE53 4Matic coupe and cabriolet. It is also planned to be brought to the facelifted second-generation GLC due in 2027, sources familiar with the plans tell WardsAuto.
The facelifted C63 will use a re-engineered version of AMG’s M256 turbocharged 3.0L inline 6-cyl. engine. It is expected to deliver up to 480 hp, and more than 650 hp in combination with an electric motor. Torque is expected to top 650 lb. ft. (881 Nm).
In the current E53 launched in 2024, a less powerful version of this powertrain delivers a combined 576-hp and 553 lb.-ft. (750 Nm) of torque, with 443 hp and 413 lb. ft. (560 Nm) from the 6-cyl. engine alone.
Buyer resistance to AMG’s 4-cyl. PHEV already has led to a decision to bring back V-8 power in other parts of its lineup. The upcoming CLE63 coupe and cabriolet – the indirect successors to the E63 coupe and E63 cabriolet due to be revealed by the end of 2025 – get a flat-plane-crank version of AMG’s M177 twin-turbocharged 4.0L V-8, rather than the complex 4-cyl. plug-in hybrid drivetrain currently used in the C63.
Having a CLE63 with 4-cyl. power positioned above the 6-cyl. CLE53 would have made little sense to customers, according to Stuttgart sources.
Engineers involved in the C-Class program say packaging constraints within the existing C-Class’s MRA platform make the adoption of the new V-8 engine unfeasible.
“It requires more space, not just in terms of physical dimensions but also for associated cooling systems and crash protection measures,” WardsAuto is told.
The current C-Class engine bay, optimized around 4-cyl. and 6-cyl. engines, would require significant structural changes to accommodate the V-8. Those changes likely would require a fresh round of crash testing and regulatory approval, which Mercedes-Benz sources suggest is not viable at this stage.
The 6-cyl. M256’s relatively compact packaging, a result of it using a 3.5-in. (88.9-mm) bore spacing, makes it well-suited to the C-Class platform, unlike the larger M177 V-8. With this setup, AMG hopes to balance performance targets with a return to the smoother, more characterful delivery associated with the earlier V8-powered C63.
The decision to adopt 6-cyl. power places the next C-Class on the same mechanical path as the BMW M3, which has used a 6-cyl. since 2000.
Other changes set for AMG’s new C-Class performance model include the adoption of a new dashboard featuring a “superscreen” display in combination with Mercedes-Benz’s MB:OS operating system.
