Mercedes-AMG's Most Hated Engine Is Being Replaced

Miami Herald

5 hours ago

In a recent interview, Mercedes-AMG CEO Michael Shiebe admitted that converting fans of the brand's old V8 to the newer four-cylinder plug-in hybrid in the C63 has been a challenge. Prior to that, he said some customers have been lost in the midst of the brand's downsizing exercise. No intention to formally discontinue the four-pot engine was proposed, but that now seems to be happening, with a senior insider confirming that this unloved powertrain will be phased out in favor of larger inline-six and V8 mills.
"Technically, the four-cylinder is one of the most advanced drivetrains available in a production car," said the source who spoke to Autocar. "It's also right up there on performance. But despite this, it failed to resonate with our traditional customers. We've recognized that."
Mercedes would not necessarily have to develop a new engine from scratch for smaller AMG models. In the E53 AMG, for instance, the company uses a 3.0-liter six-cylinder turbocharged hybrid that produces 577 horsepower and 553 lb-ft of torque. It's not a direct BMW M5 rival, but it's not far off in terms of performance, either. This engine in a smaller AMG model could make for a special performance car.
More exciting is the possibility of a new flat-plane crank V8, not dissimilar from the one in the GT Black Series. Whatever replaces the four-cylinder unit, it's sure to mark a return to the emotional character that has defined AMG models for so long.
The current C63 S E Performance is a heck of a performer, boasting 671 hp and 752 lb-ft, but the previous V8-powered C63 set a high bar that it hasn't been able to surpass, no matter how quick it is.
The GLC 63 S E Performance shares the C63's 671-hp four-cylinder plug-in hybrid, so is also in line to get either a bigger six- or eight-cylinder engine in the years ahead. A notch below these full-fat AMG models are the AMG SL 43 Roadster and C43 sedan, both of which use a 416-hp version of the M139 four-cylinder engine. In a car of the SL's caliber and price, the use of a four-cylinder has been especially contentious, so we expect these models to ditch the 2.0L engine for a larger Six.
Other than its more ordinary soundtrack, there's another reason to phase out the M139: It won't be easy or cost-effective to get it to comply with new Euro 7 emissions regulations.
"There's no doubt about its potential - this is one of the most sophisticated engines we've ever built - but the investment to make it EU7-compliant is very high," said the insider.
Related: 2025 Mercedes-AMG C 63 S E Performance First Drive: Overkill through complexity
Markus Schäfer, Mercedes CTO, said at the same event that EVs and hybrid gas engines will continue being developed in tandem, and that the new V8 "will support upcoming emissions regulations." Both six- and eight-cylinder engines will use either 48V or full hybrid systems.
Ultimately, Merc's four-cylinder plug-in hybrid powertrain looks like it will only last for a single generation, although a specific timeline wasn't given. Over time, it may come to be regarded as a rare misstep in AMG's legacy. That's only if you're a cylinder snob like most enthusiasts, of course; the current C63 and GLC 63 are brilliant performance vehicles in many respects. But their incredible technical achievements came at the expense of the emotional qualities of their predecessors.
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