A significantly updated Mercedes-Benz S-Class sedan will reportedly be revealed this year, powered by a more powerful V8 petrol engine the automaker has confirmed will use a flat-plane crankshaft.
The new engine is part of what Mercedes-Benz describes as the “most extensive update in one generation”.
According to Autocar, the current seventh-generation S-Class is set to receive a major overhaul in the coming weeks, including an updated exterior design, a substantially upgraded cabin, and the aforementioned V8 engine.
A flat-plane crankshaft not only gives an internal combustion engine (ICE) a distinctive timbre, but also offers performance advantages such as reduced weight and the ability to spin faster, delivering a higher-revving and more responsive engine.
Mercedes-AMG moved to a flat-plane crank with the 2020 AMG GT Black Series, where its 4.0-litre twin-turbocharged V8 – codenamed M178 LS2 – produced 537kW between 6700 and 6900rpm, and 800Nm between 2000 and 6000rpm.
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For the updated 2026 S-Class, Autocar reports the new M177 V8 will replace the previous M176 engine’s cross-plane crankshaft with a flat-plane design, while retaining its 4.0-litre capacity and twin turbochargers mounted within the engine’s vee.
The M177 engine family is already found in cross-plane form under the bonnets of several Aston Martin models, including the DB12 and DBX SUV, and will be introduced in the S580 as part of a mild-hybrid setup. The move to a flat-plane crank is also expected to help reduce emissions.
Mercedes-Benz told Autocar the updated engine will deliver more power, with output rising from the previous V8 S-Class’s 370kW to around 395kW, enabling a claimed 0–100km/h acceleration time of approximately 4.0 seconds.
With the production reveal only weeks away, six-cylinder engines will power lower-spec S-Class models, though the automaker has not yet confirmed details of the more potent performance-focused S63 AMG.
Mercedes-Benz Australia hasn’t confirmed local timing for the updated S-Class, though it has confirmed an update for the V8-powered Maybach SL in the second half of 2026.
News of the revised V8 comes after Mercedes-Benz chief technology officer Markus Schäfer told media that production of V8 and V12 ICE engines will continue.
The brand confirmed earlier in 2025 it was developing a “full range of future-proof [Euro 7 emission standards] ready engines ranging from four to eight cylinders”.
A plug-in hybrid version of the V8 was introduced on the AMG GT four-door, while Mercedes-Benz also offers four- and six-cylinder PHEVs across other models.
This follows the brand’s decision to pull back from its earlier electric vehicle (EV) ambitions, as well as its admission that replacing the V8 in the C63 with a four-cylinder PHEV was a mistake following customer backlash.
Crosstown rival BMW is developing both an ICE-powered version of the M3 – the C63’s arch-rival – and an electric M3 on a separate platform, with the Munich-based brand also committed to V8 engines for the future.
Mercedes-Benz will nevertheless continue to develop EVs, both across its regular lineup and for performance models, including the 1000kW Concept AMG GT XX electric supercar.
“AMG will continue with a dual strategy – two pillars. The electric pillar will grow significantly. But the second pillar – hybridised internal-combustion engines – will also remain,” Mr Schäfer told journalists in mid-2025.