Mercedes-Benz will shortly reveal a dramatically overhauled version of the S-Class for 2026 – complete with a fresh look, uprated interior tech and a new V8 with a flat-plane crankshaft.
The company said this is the “most extensive update in one generation” for its flagship saloon, which is in its seventh generation, having been launched in 1972.
More than 50% of the components have been redeveloped or re-engineered for this facelift, with the refreshed S-Class “taking a leading role in the most ambitious product launch programme in Mercedes-Benz history”.
The camouflage is set to come off in the next few weeks, as prototypes of the revamped S-Class are said to be “very close to series production” – and Autocar was invited on board as road testing entered its final phase (see below).
Full details of the changes under the skin are yet to be revealed, but Autocar has been told that the ‘M176’ V8 in the most potent S-Class variants will be replaced by a new M177 engine that swaps the conventional cross-plane crankshaft for a flat-plane design – like in the old AMG GT Black Series.
The ‘M177’ – still 4.0 litres in capacity and twin-turbocharged like its forebear – already features in various top-drawer AMG models (including the S63), as well as the Aston Martin DB12, DBX and Vantage – but the mild-hybrid S580 will be the first to use the new flat-plane-crank format.
The ultra-luxurious Maybach S580 will follow shortly after, with the same engine cranked to 603bhp to replace the V12 it currently uses, which Mercedes will retire in Europe.
There’s no word on when AMG will reveal the updated S63, but it will no doubt follow suit. The engine is also set to be introduced to other top-link AMG models, including the upcoming CLE 63.
A flat-plane crank has its pins arranged at 180deg intervals around the shaft, giving a flat end-on profile, while a traditional cross-plane V8 has its pins at 90deg intervals, giving an X-shaped profile – hence the names.
The two can be most obviously told apart by their soundtracks, with a cross-plane V8 characterised by the off-beat, low-rev ‘burble’ that comes with an uneven firing order, while a flat-plane crank engine has evenly spaced firing and has a distinctive higher-pitched engine note at high revs.
The move, engineers told Autocar, will help to reduce emissions, but not at the expense of power: the new engine increases output from 496bhp to 530bhp, which should help trim the S580’s 0-62mph sprint time down closer to 4.0sec.