22 MPG combined won’t win any green awards, but it’s acceptable for the 2019 Mercedes-Benz S450. This car prioritizes peerless comfort, effortless performance, and a sense of arrival that few other vehicles can match. Owners of the S450 aren’t typically cross-shopping economy cars. They’re prioritizing a quiet and cosseting experience, and are willing to accept mid-pack fuel consumption as a tradeoff.

City and highway performance

The EPA estimates for the 2019 S450 peg city driving at 19 MPG and highway cruising at a more respectable 28 MPG. That difference isn’t accidental. The S450, with its meticulously engineered suspension, is designed to excel on long journeys. Its smooth 3.0L inline-six, paired with the nine-speed automatic, settles into an almost silent hum on the open road, making highway miles disappear. Stop-and-go city driving inevitably takes a toll, but even there, the car’s refined start/stop system and carefully calibrated throttle response help to mitigate fuel waste. Ultimately, the S450 is happiest stretching its legs on the highway, a trait reflected in its fuel economy figures.

Annual fuel cost

The EPA estimates that the annual fuel cost for the 2019 Mercedes-Benz S450 will be $2,650. This figure is based on driving 15,000 miles per year and using the national average fuel price at the time of the EPA’s testing. Individual fuel costs will vary based on driving habits, location, and current fuel prices, of course. But the $2,650 provides a useful benchmark for understanding the S450’s place in the broader automotive landscape from a running cost perspective. It’s a figure that prospective buyers should consider alongside the vehicle purchase price, insurance rates, and maintenance expenses when evaluating the total cost of ownership. For shoppers curious about fuel economy across the lineup, they can explore all Mercedes Benz fuel economy data.

Real-world expectations

While the EPA estimates provide a useful comparison tool, real-world MPG often differs. S450 drivers who frequently engage in spirited acceleration or spend most of their time in congested urban environments are likely to see numbers closer to the city rating, or even slightly below. Conversely, those who predominantly drive on the highway, employing a smooth and consistent style, may find their MPG edging closer to, or even exceeding, the 28 MPG highway estimate. Regular preventative maintenance, including timely oil changes and air filter replacements, can also contribute to maintaining optimal fuel efficiency. Drivers can research S450 MPG across all years to compare various model years.

How it compares

The long-wheelbase BMW 740i, a direct competitor to the S450, posts EPA ratings of 22 MPG combined, 20 city, and 29 highway, making it virtually identical in overall efficiency. The Lexus LS 500 fares slightly better, boasting 23 MPG combined, 19 city, and 30 highway. The differences are subtle, but buyers focused on minimizing running costs should note them. The Audi A8, another contender, achieves 21 MPG combined, 19 city, and 28 highway, placing it in a similar category to the S450 and BMW 740i. None of these contenders are fuel sippers, but the small differences reveal slight engineering or powertrain variations. Each luxury sedan prioritizes different aspects of the driving experience, and fuel economy is just one data point that buyers use to select a vehicle.

Tips to maximize efficiency

Gentle acceleration is key to maximizing fuel efficiency in the S450. The turbocharged engine delivers ample torque at low RPMs, so there’s no need to aggressively apply the throttle. Avoid “jackrabbit” starts from stoplights, and instead, aim for smooth and progressive acceleration. This will allow the nine-speed automatic transmission to shift efficiently, keeping the engine in its most economical operating range.

Use the car’s driving modes to your advantage. The “Eco” mode, if equipped, optimizes various vehicle systems for fuel efficiency, including throttle response, transmission shift points, and even climate control settings. While it may slightly reduce performance, the gains in fuel economy can be significant, particularly during city driving. Be aware that aggressively using the accelerator will override Eco mode calibrations.

Maintain proper tire inflation. Under-inflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressures regularly, at least once a month, and ensure they are inflated to the recommended levels as indicated on the doorjamb sticker. A simple tire pressure check and adjustment can provide better safety and improve your gas mileage.

Minimize idling. Modern vehicles consume a surprising amount of fuel while idling. Avoid unnecessary idling situations, such as warming up the engine for extended periods in cold weather (idling is rarely needed in modern cars) or waiting in parked for long stretches of time. If you anticipate being stationary for more than a minute or two, it’s more fuel-efficient to simply turn off the engine.