According to Automotive News, the new nomenclature will make its debut on the next generation CLS and use a variation of Benz's 3.0-litre turbocharged straight-six codenamed M256, developing a reported 430 horsepower or 320 kW. It will also likely employ a 48-volt electric motor similar to that of the recently launched S-class.
It also claims that the new 53 range could include examples of the E-class cabriolet and coupe, while the sedan and estate will continue with the E63 only.
Spotted on a number of occasions undergoing testing, the next CLS will reportedly ride on the E-class' MRA underpinnings, and like the previous models, use the same range of petrol and diesel engines all linked to a 9G-Tronic gearbox. Reports have meanwhile suggested that Mercedes-Benz will take the covers of the new CLS at the Los Angeles Motor Show in November.