The exact MPG any engine gets depends on the vehicle it's used in, but the 6.6-liter Duramax diesel engine gets an EPA-estimated 15 MPGs in city driving and 20 MPGs on highway driving in the 2011 Chevrolet Silverado. Other trucks using the engine offer comparable ratings.
Even though it's a diesel engine, the 6.6-liter Duramax rates poorly in terms of mileage due to its 8-cylinder engine, but the torque it provides makes it useful in trucks. First released in 2001 Chevrolet vehicles, the engine has seen improvements in power and torque over the years, and some Chevrolet vans and other vehicles offer it as an option for buyers looking for a more powerful engine.
