Typically, a Mercedes-Benz that uses diesel is more fuel efficient than one that uses gas. Diesel engines get great mileage with 25- to 30-percent more fuel economy compared to similar gasoline engines.
Diesel has a high density; this means it contains more usable energy than gasoline and delivers a better fuel economy. Besides fuel efficiency, a Mercedes-Benz with a diesel engine has lower repair costs; a diesel engine usually goes for many miles before needing a major repair. The diesel engine is built to withstand the rigor of high compression. Other benefits include lack of spark plugs and distributors, so they do not need ignition tune-ups.