2026 Mercedes-AMG C63 Rumored to Get Six-Cylinder PHEV Powertrain

It may not be the V8 some were hoping for, but the 2026 Mercedes-AMG C63 will reportedly get a potent I-6 to replace its existing I-4.

Much ado was made about Mercedes’ decision to ditch its beloved V8 in the C63 some time ago, replacing it with a turbocharged 2.0-liter four-cylinder engine, coupled with a rear-mounted electric motor in the C63 S E Performance. That combination is indeed potent – churning out 671 horsepower and 752 pound-feet of torque, but folks haven’t exactly gravitated toward this model, as sales have, well, fallen a bit behind expectations. Thus, perhaps it comes as no surprise to learn that the 2026 Mercedes-AMG C63 will reportedly swap out that four-cylinder with a six-cylinder powerplant.

According to Autocar, the 2026 Mercedes-AMG C63 will be treated to a mid-cycle refresh – one that involves a pretty big change in terms of what motivates the sporty sedan. That is rumored to be the same twin-turbocharged 3.0-liter inline-six cylinder gas engine and electric motor combo that’s quite similar to the PHEV setup present in the E53, GLE 53, and CLE 53, albeit, with a bit more juice.

It may not be the V8 that fans have been clamoring for, but this particular powertrain has proven impressive in those models, and it quite V8-like in terms of its low-end power and more pleasant exhaust note. As it turns out, the current MRA platform present in the C-Class also presents some packaging constraints that make a V8 unfeasible. Such a thing would require “significant structural changes,” meaning that the C-Class would have to undergo crash testing and regulatory approval yet again. “It requires more space, not just in terms of physical dimensions but also for associated cooling systems and crash protection measures,” a source stated.

Thus, the 2026 Mercedes-AMG C63 will instead reportedly get a more potent version of the existing M256 I-6, which is slated to churn out 650 horsepower and more than 650 pound-feet of torque with electric assist, which is quite a bit more than the 577 horsepower (or 604 in Race Start mode) and 553 pound-feet of torque it makes in the E53. Perhaps more interesting is the fact that M-B will allegedly swap out that powertrain’s rear-mounted electric motor for one that’s sandwiched in between the engine and transmission, too.

While purists would undoubtedly prefer to see a V8 in the C63 like the good old days, that just doesn’t seem to be feasible – at least, until the C-Class gets a more proper redesign, and even then, emissions standards may prevent it from happening. Regardless, the arrival of this well-received I-6 may be just what the C63 needs to entice performance-focused luxury sedan shoppers to plunk down their hard-earned money for one.

Photos: Mercedes-Benz

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Brett Foote

Brett Foote has been covering the automotive industry for over five years and is a longtime contributor to Internet Brands’ Auto Group sites, including Chevrolet Forum, Rennlist, and Ford Truck Enthusiasts, among other popular sites.

He has been an automotive enthusiast since the day he came into this world and rode home from the hospital in a first-gen Mustang, and he's been wrenching on them nearly as long.

In addition to his expertise writing about cars, trucks, motorcycles, and every other type of automobile, Brett had spent several years running parts for local auto dealerships.

You can follow along with his builds and various automotive shenanigans on Instagram: @bfoote.