27 MPG combined isn’t going to set any records, but for the 2015 Mercedes-Benz GLK250 Bluetec 4matic, it represents a sweet spot of diesel efficiency and luxury SUV practicality. GLK250 buyers likely weren’t prizing fuel economy above all else. They wanted a comfortable, reasonably sized, and premium vehicle that could handle whatever the road and weather threw their way. But with the end of the GLK after 2015, owners understand its historical significance and desire efficient operation from their unique diesel SUV.

City and highway performance

The EPA numbers break down to 24 MPG in the city and 32 MPG on the highway. This spread reflects the strengths and limitations of the GLK250’s 2.1L turbodiesel engine. Around town, the diesel’s strong low-end torque allows for relaxed acceleration without needing to dig deep into the throttle. That 24 MPG beats many gasoline-powered competitors in similar city driving conditions. Out on the open road, that highway figure puts the GLK250 in the same ballpark as some smaller, less powerful cars, all while providing a comfortable, stable ride and the confidence-inspiring grip of 4Matic all-wheel drive. The seven-speed automatic transmission is mostly responsible for the impressive highway economy, as it keeps the engine humming at a miserly RPM.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2015 Mercedes-Benz GLK250 Bluetec 4matic at $2,050. This figure is based on driving 15,000 miles per year and using national average fuel prices when the EPA performed its calculations. Your actual fuel costs will vary depending on your driving habits, the type of driving you do, and the current price of diesel fuel in your area. Given that diesel prices can fluctuate more than gasoline, it’s wise to keep an eye on fuel costs to understand the true cost of ownership for your GLK250. Diesel fuel typically contains considerably more potential energy than gasoline fuel; that makes diesel one of the most efficient combustion fuels on Earth.

Real-world expectations

While the EPA ratings are a good starting point, real-world fuel economy can vary. Some GLK250 owners report achieving slightly higher figures on the highway, especially on long road trips where they can maintain a steady speed. However, city driving with frequent stop-and-go traffic can bring the MPG closer to, or even slightly below, the EPA estimate. Factors like driving style, tire pressure, and the use of accessories like air conditioning can also impact fuel consumption. Colder weather months can have a negative impact on fuel economy, as cold diesel fuel thickens, and Mercedes-Benz engineers made the decision to initiate auxiliary heaters to assist with faster engine warm-up. Be aware that shorter drives will also negatively impact economy, as the engine needs time to reach its optimal operating temperature.

How it compares

Compared to its gasoline-powered sibling, the GLK350, the GLK250 offers a clear advantage in fuel economy. The GLK350 achieves around 21 MPG combined, significantly less than the 27 MPG of the diesel. Against competitors like the Audi Q5 2.0 TDI (around 28 MPG combined), the GLK250 is closely competitive in terms of fuel efficiency. But against a gasoline-powered BMW X3 xDrive28i (around 24 MPG combined), the GLK250 is a clear winner. This is a key consideration for buyers who wanted the practicality of a luxury SUV without the fuel bill of a larger, less efficient vehicle. Explore all Mercedes Benz fuel economy data to see how the GLK250 stacks up across the brand.

Tips to maximize efficiency

Minimize idling, especially during cold starts. Diesel engines, while efficient, don’t warm up as quickly as gasoline engines, and prolonged idling simply wastes fuel. Start moving soon after starting the engine, but avoid aggressive acceleration until the engine reaches its operating temperature.

Monitor your tire pressure religiously. Underinflated tires create more rolling resistance, which negatively impacts fuel economy. Check your tire pressure at least once a month and inflate them to the recommended pressure listed on the sticker inside the driver’s side door jamb. Note that the ideal pressures listed are for standard OEM tires; aftermarket sizes may require different pressures.

Use cruise control on the highway whenever possible. Maintaining a consistent speed eliminates unnecessary acceleration and deceleration, which can significantly improve fuel economy. However, be mindful of traffic conditions and avoid using cruise control in hilly terrain where the transmission may frequently downshift, negating some of the benefits.

Service your GLK250 according to the recommended maintenance schedule. Regular oil changes, air filter replacements, and fuel filter maintenance ensure that the engine is running optimally and efficiently. Clogged filters or degraded oil can reduce fuel economy. Considering the unique engine, it is critical to service the vehicle with parts that meet Mercedes-Benz standards.

Avoid unnecessary weight. Carrying heavy items in the cargo area increases the vehicle’s weight, which in turn reduces fuel economy. Remove any unnecessary items from the car to minimize weight and improve fuel efficiency. Be especially aware of the extra weight added by roof racks and storage carriers.

The 2015 Mercedes-Benz GLK250 Bluetec 4matic presents a blend of luxury, practicality, and impressive diesel fuel efficiency. Understanding its real-world MPG nuances, especially with its 4Matic all-wheel-drive system, is key to appreciating its place in the automotive landscape. To dive deeper, investigate GLK250 MPG across all years.