Mercedes-AMG C 63 and GLC 63 to lose four-cylinder engine

Although the current Mercedes-AMG C 63 and GLC 63 are the most powerful models ever produced, with 680 hp, their combination of the inline four-cylinder M 139L engine and a rear-axle electric motor has not won over the market. It appears that buyers still wanted the V8 from the previous generation.

Affalterbach has had to acknowledge the reality. Speaking to Autocar during the presentation of the Mercedes-AMG Concept GT XX, a company representative admitted: “From a technical perspective, the four-cylinder is one of the most advanced powertrains ever fitted to a production car. Its performance is exceptional. Yet, despite that, it did not appeal to our traditional customers. We recognise that.”

Those long-standing AMG customers have criticised the hybrid powertrain for its lack of character, as well as the car’s considerable weight - the C 63 weighs 2,165 kg. There is now encouraging news for these enthusiasts: the four-cylinder will be dropped. However, that will not happen immediately.

The representative did not say when the change would take place, but all signs point to it coinciding with the introduction of the Euro 7 emissions standard on 29 November 2026. According to him, the cost of bringing the M 139 into line with the new requirements is simply too high.

This will affect not only the C 63 and GLC 63, but also the GT 43 and SL 43, as well as the 45 models in the German brand’s lower ranges, including the A-Class and CLA.

A future with more cylinders

It remains unclear whether AMG will return to four-cylinder engines in the future, but its strategy for the coming years will rest on two pillars: electric models and electrified combustion engines - with more cylinders.

For electric vehicles, the Concept GT XX provides a preview of what to expect from the brand’s future high-performance EVs: axial-flux motors, which are more compact and lighter while delivering greater power, alongside exceptionally high charging capability of 850 kW.

As for combustion engines, Mercedes-Benz chief technical officer Markus Schäfer has confirmed that the inline six-cylinder and V8 units will continue, “all electrified, with mild-hybrid (48 V) or plug-in hybrid systems”.

The biggest development seems to concern the V8. AMG is developing a new-generation unit with a flat-plane crankshaft, Ferrari-style, which will already be designed to comply with Euro 7.

What does the future hold for the C 63?

Despite these developments, the C 63’s future is still uncertain. The departure of the four-cylinder engine does not automatically mean the model will receive a V8 or inline six-cylinder successor.

Rumours suggest that both the C 63 and the C 43 - currently powered by four-cylinder engines - could be replaced by a new C 53, using the M 256M inline six-cylinder already found in models such as the E 53.

There is, however, a technical point to consider. When the current C-Class, the W 206, was unveiled in 2021, Mercedes made clear that only four-cylinder engines would fit in its engine bay. The inline six-cylinder is too long.

Paradoxically, fitting the V8 may be easier because it is shorter than the six-cylinder - perhaps the V8 will make a return?