An 18 MPG combined fuel rating won’t impress, and it certainly increases costs at the gas pump, but that’s what you get with the 2018 Mercedes-Benz AMG GLC63 4matic. This SUV has a hand-built, 4.0-liter, twin-turbocharged V8 that allows it to outperform sports cars on winding roads. This isn’t a vehicle for those watching every penny; it’s for enthusiasts who value performance and exclusivity.

City and highway performance

The EPA estimates the GLC63’s city fuel economy at 16 MPG and highway at 22 MPG. The city number reflects stop-and-go traffic where the large displacement engine and turbo lag result in burning more fuel. The highway number is better, but still far from the 30+ MPG figures many modern crossovers achieve.

The automatic 9-speed transmission tries to keep the engine in its optimal range, but you’re still driving a heavy vehicle powered by a high-performance V8, so physics takes over. The highway number will likely drop quickly if you accelerate aggressively.

Annual fuel cost

The EPA calculates the annual fuel cost for the 2018 Mercedes-Benz AMG GLC63 4matic to be approximately $3,200. This assumes 15,000 miles driven per year and fuel prices based on national averages. That is a large cost, easily exceeding the typical fuel costs of more economical vehicles by $1,000 or more each year. Owners should expect to pay even more, considering the vehicle encourages aggressive driving. Remember this figure when you’re reviewing all Mercedes Benz fuel economy data.

Real-world expectations

While the EPA provides a standardized benchmark, real-world MPG for the GLC63 can vary depending on driving style and conditions. Aggressive acceleration, frequent hard braking, and extended idling will all reduce fuel economy. However, a careful driver who anticipates traffic and maintains consistent speeds can get closer to the EPA’s figures. The AMG exhaust note and the instant power are tempting, making restrained driving difficult.

How it compares

The GLC63 is in a niche market of high-performance compact SUVs. A comparable Porsche Macan Turbo, with its own turbocharged V6, achieves slightly better numbers, around 17 MPG city and 23 MPG highway. The BMW X3 M Competition, another direct rival, is rated at 14 MPG city and 19 MPG highway. Even looking at “slower” models, like the GLC43 AMG with a V6, you’ll find only marginally better fuel economy, typically just a few MPG, for something a lot less exciting. A buyer considering the GLC63 understands this and accepts the trade-off for the performance and driving experience. If fuel economy is a primary concern, looking at the AMG MPG across all years might reveal better options, but they won’t deliver the same thrill.

Tips to maximize efficiency

While the GLC63 isn’t designed for frugality, you can minimize fuel consumption in a few ways. Avoid aggressive acceleration and hard braking. The GLC63’s power is alluring, but gentle inputs on the throttle during city driving can improve fuel economy.

Maintain optimal tire pressure. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressure regularly and inflate them to the recommended levels. Consult the sticker on the driver’s side doorjamb for the correct pressure for your GLC63.

Use the “Comfort” mode. The GLC63 has multiple driving modes that alter engine mapping, transmission behavior, and suspension settings. Selecting “Comfort” mode softens throttle response and encourages earlier upshifts, which helps fuel efficiency during everyday driving. Save your “Sport+” mode for performance driving.

Minimize idling. Idling consumes fuel. If you anticipate being stopped for more than a minute, turn off the engine. The GLC63 has a stop-start system that automatically shuts off the engine at traffic lights, reducing fuel consumption. Keep the stop-start system enabled.

Remove any unnecessary items from the GLC63 to reduce weight, as extra weight reduces fuel efficiency. Carrying around heavy items in the trunk adds strain to the engine and reduces gas mileage. Only keep what is needed.