Beginning next year, the U.S.-market E-Class and M-Class will get an optional diesel four.

Have the diesel floodgates opened? Chevrolet, Mazda and Jeep have plans to bring new oil-burning motors to the states next year, Audi is preparing to expand its diesel lineup from two to six models, and now a new report suggests that Mercedes-Benz will soon install a new diesel in a pair of its U.S.-market models as well.

Mercedes will offer a 2.1-liter turbodiesel inline-four as an option in the E-Class sedan and M-Class SUV starting next year, according to a Car and Driver report. Essentially the same mill utilized by the GLK250 BlueTEC that's set to hit the market this spring, the motor is expected to produce 190 horsepower and a stout 369 lb-ft of torque.

In the E-Class, the 2.1-liter unit will sit under the hood of a new E250 BlueTEC 4MATIC model that will replace the current E350 BlueTEC, which uses a 3.0-liter turbodiesel V6. Look for the E250 to launch a few months after the facelifted 2014 E-class debuts at the Detroit show in January.

The M-Class variant will wear similar ML250 BlueTEC badging, although at this point it's unclear whether it will replace or supplement the existing ML350 BlueTEC model.

While no fuel economy estimates have been released, expect Mercedes' new four-cylinder diesel models to improve upon the already-respectable mileage of the six-cylinder E350 BlueTEC and ML350 BlueTEC, which return 22/32 mpg and 20/28 mpg, respectively.

Mercedes' C-Class sedan will also eventually get a diesel powerplant, but likely not until the next-generation model launches in 2014.