Reports indicate that a significantly updated Mercedes-Benz S-Class sedan will be unveiled later this year, featuring a more powerful V8 petrol engine that the automaker has confirmed will use a flat-plane crankshaft. The new engine forms part of what Mercedes-Benz has described as “the most extensive update within a single generation.”

According to overseas media, the current seventh-generation S-Class is set to undergo a major facelift in the coming weeks. The update will include refreshed exterior styling, a substantially upgraded cabin, and the introduction of the new V8 engine.

A flat-plane crankshaft not only gives an internal combustion engine a distinctive sound character, but also provides performance advantages such as reduced weight and the ability to rev higher, resulting in a more responsive, high-revving engine.

Previously, Mercedes-AMG adopted a flat-plane crankshaft in the 2020 AMG GT Black Series, which was powered by a 4.0-litre twin-turbocharged V8 engine codenamed M178 LS2. This engine produced 537 kW at 6,700–6,900 rpm and 800 Nm of torque between 2,000 and 6,000 rpm.

For the facelifted 2026 S-Class, Autocar reports that the new M177 V8 engine will replace the cross-plane crankshaft of the previous M176 engine with a flat-plane design, while retaining its 4.0-litre displacement and twin turbochargers mounted within the engine’s V.

Mercedes-Benz has told the media that the updated engine will deliver increased output, rising from 370 kW (503 PS) in the previous V8-powered S-Class to around 395 kW (537 PS). This is expected to enable a 0–100 km/h acceleration time of approximately 4.0 seconds.

Entry-level S-Class models will continue to be powered by six-cylinder engines, while details of the high-performance S63 AMG variant have yet to be confirmed.

Source: Autocar