Mercedes-AMG has announced a new model line that will slot in between its 43 and 63-badged cars – shocker – the new series will carry a 53. 

The CLS, E-Class Coupe and E-Class Cabriolet will get the new badge, characterised by a brand new inline-six engine that sees Mercedes ditching the V6 in favour of a familiar old layout that allows for improved packaging.

Styling tweaks for the 53 cars include a twin-blade radiator grille, front apron in A-wing design, AMG-specific side sill panels, a diffuser insert in the rear bumper and exhaust tailpipes in high-gloss chrome.

The new 3-litre engine gets F1-style twin-turbo technology, with an exhaust gas turbocharger and electric auxiliary compressor that help improve efficiency and create plenty of power for the car to exploit. 

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Gallery: 2018 Mercedes-AMG CLS53

In fact, the new in-line six generates 429bhp and 384lb ft torque, which in the CLS makes for a 0-62mph time of 4.5 seconds. Economy of around 33mpg can be expected, as well as CO2 emissions of around 201g/km depending on the model. 

The new 3-litre engine’s efficiency is further boosted by a 48V mild hybrid electric system that sees the engine doing away with an auxiliary belt at the front of the unit and alternator duties being taken over by Mercedes’ EQ Boost starter/alternator. 

The beefier electrical system can be turned off for longer, stopped and started more often and even has a coast function so that the engine can be turned off on the move. The improved packaging also means that the catalytic converter can be placed much closer to the engine to improve emissions. 

The 3-litre inline six is part of a new modular series of Mercedes engines that aim to cut costs by sharing parts and improving packaging to allow for hybridisation and more widespread introduction of 48V systems such as the one used here. The engine will be available in four-, six- or eight-cylinder guise. 

The 53-series models on the CLS and E-Class Coupe/Cabriolet cars will be available to order soon from Mercedes, with further debuts as Mercedes updates other cars in its range. 

AMG engine range at a glance

43 – 3-litre twin-turbo V6
45 – 2-litre twin-turbo inline-four
53 – 3-litre twin-turbo inline-six
63 – 4-litre twin-turbo V8
65 – 6-litre twin-turbo V12

Gallery: 2018 Mercedes-AMG E53 Coupe and Cabriolet