19 MPG combined. It’s the number associated with the 2015 Mercedes-Benz GL450 4matic. This isn’t a vehicle purchased for saving fuel, it’s bought by families who prioritize space, luxury, and the confidence that comes with the Mercedes-Benz brand, accepting fuel cost as a necessary part of ownership. The GL450 serves a specific clientele: those who need a spacious, opulent SUV and are willing to pay for it at the dealership and the gas station.

City and highway performance

The GL450’s EPA ratings are 17 MPG in the city and 21 MPG on the highway. The city figure reflects the challenge of moving a heavy vehicle through stop-and-go traffic. The 3.0L V6 engine, turbocharged for sufficient power, needs a significant amount of fuel to overcome inertia. On the open road, the 21 MPG highway rating is more attainable, especially with careful driving. However, aggressive acceleration, frequent passing, or sustained high speeds will reduce that number. The 7-speed automatic transmission helps optimize fuel consumption, but physics determine the outcome when moving a vehicle of this size and weight.

Annual fuel cost

The Environmental Protection Agency estimates the annual fuel cost for the 2015 Mercedes-Benz GL450 4matic at $3,050. This is based on driving 15,000 miles per year, with a mix of city and highway driving, and using national average fuel prices. Individual fuel expenditures will vary depending on driving habits and local fuel costs, but the $3,050 figure provides a benchmark for potential owners. It’s a significant sum, and potential buyers must realistically consider it when planning for the cost of ownership of a large luxury SUV like the GL450.

Real-world expectations

EPA estimates provide a baseline, but real-world fuel economy often differs. GL450 drivers who frequently drive in congested urban areas or accelerate quickly can expect to see numbers closer to the 17 MPG city rating, or even lower. Alternatively, those who primarily use the vehicle for long highway trips and accelerate gently may achieve numbers closer to, or even exceeding, the 21 MPG highway estimate. Tire pressure, vehicle maintenance, and cargo weight also affect actual fuel consumption. Browse GL450 MPG across all years to get a sense of what other owners report.

How it compares

Among large luxury SUVs, the GL450’s fuel economy is roughly average. A contemporary BMW X5 xDrive35i, with its 3.0L turbocharged inline-six, offered a slightly better 20 MPG combined. The Land Rover Range Rover Sport with its supercharged V6 also achieved around 19 MPG combined, demonstrating similar fuel use. An Audi Q7 from the same period, depending on the engine, could achieve slightly better or comparable fuel economy. The key difference can be the driving experience and brand reputation that influence buyers to choose one model. Those wanting better fuel efficiency within Mercedes-Benz might explore all Mercedes Benz fuel economy data to identify more economical options.

Tips to maximize efficiency

Regular maintenance is critical for maximizing gas mileage. Ensure your GL450 receives timely oil changes, air filter replacements, and tire rotations. A well-maintained engine operates more efficiently. Properly inflated tires reduce rolling resistance, which improves fuel economy.

Avoid unnecessary idling. Modern engines can be turned off and restarted without causing excessive wear. If you anticipate being stopped for more than a minute, switching off the engine can save fuel, especially in urban driving.

Drive smoothly. Aggressive acceleration and hard braking consume more fuel. Watch traffic flow, maintain a steady speed, and avoid sudden maneuvers. The GL450’s abundant torque makes smooth acceleration attainable.

Reduce weight. The more weight the GL450 carries, the more fuel it consumes. Remove unnecessary items from the vehicle, especially heavy objects that are being carried unnecessarily. Only carry the passengers you need to.

Consider using cruise control on the highway. Cruise control helps maintain a consistent speed, which can improve fuel economy on long journeys. Cruise control may not be efficient in hilly terrain, where the system may downshift to maintain speed, increasing fuel consumption. Change your speed manually for efficiency, depending on road conditions.