24 MPG combined isn’t going to win the 2021 Jeep Gladiator Rubicon EcoDiesel any fuel-sipping awards, but let’s be honest: no one choosing this supremely capable off-road pickup is prioritizing Prius-like efficiency. This performance is entirely acceptable within the context of this specific vehicle’s mission. The EcoDiesel Gladiator exists for those who demand serious torque for conquering trails, overlanding adventures, and the occasional tow, while still retaining some semblance of daily drivability.

City and highway performance

The EPA estimates the 2021 Jeep Gladiator Rubicon EcoDiesel at 21 MPG in the city and 27 MPG on the highway. These figures reflect the realities of lugging around a solid front axle, strong four-wheel-drive system, and aggressive off-road tires. The city MPG suffers, as expected, from stop-and-go traffic and the engine working harder to overcome the Gladiator’s considerable weight. The highway MPG is more respectable, benefiting from the engine’s efficient cruising nature and the smooth-shifting eight-speed automatic transmission, which helps keep the engine in its optimal power band. Remember that aggressive driving, especially with larger tires or added accessories, will significantly impact these numbers.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,300 for the 2021 Jeep Gladiator Rubicon EcoDiesel, based on driving 15,000 miles per year and using national average fuel prices. This is a figure that should be considered a baseline. Individual driving habits, local fuel costs, and the amount of off-roading undertaken can all drastically alter this figure. If your Gladiator sees more time crawling over rocks than cruising on the highway, expect to pay more at the pump. If you want to review all Jeep fuel economy data, it can offer valuable insights.

Real-world expectations

While the EPA provides a standardized benchmark, real-world MPG for the Gladiator EcoDiesel varies widely. Owners report numbers ranging from the high teens to low 30s, depending on driving style, terrain, and modifications. The diesel engine’s inherent efficiency shines on longer highway trips, especially when cruising at moderate speeds. However, heavy acceleration, short trips, and frequent idling will take a toll on fuel economy. Tire size and weight are also significant factors; larger, heavier off-road tires can easily drop MPG by several points.

Owners who prioritize fuel economy should stick to the stock tire size and avoid adding excessive weight.

How it compares

Compared to other mid-size trucks, the Gladiator Rubicon EcoDiesel occupies a unique space. The Toyota Tacoma TRD Pro, with its gasoline V6, typically achieves around 18 MPG combined. The Chevrolet Colorado ZR2, another off-road-focused competitor, also lands in the 17-19 MPG range with its gasoline engine. Even the gasoline-powered Gladiator Rubicon, which offers nearly identical off-road capability, sees MPG numbers in the 17-20 MPG range.

The EcoDiesel offers a clear advantage in highway MPG compared to these gasoline-powered rivals, and the torque of the diesel is a major benefit for serious off-roading. You can also review GLADIATOR MPG across all years for a wider range of comparisons.

Tips to maximize efficiency

Gentle acceleration is key to maximizing fuel economy in the Gladiator EcoDiesel. The engine produces ample torque at low RPMs, so there’s no need to aggressively accelerate from a stop. Smooth, gradual acceleration will help the engine operate more efficiently and reduce fuel consumption.

Maintain a consistent speed on the highway to improve MPG. Using cruise control can help prevent excessive acceleration and deceleration, which can significantly impact fuel economy. Avoiding speeds above 70 mph will also keep the engine in a more efficient operating range.

Keep your tires properly inflated to the recommended pressure. Underinflated tires increase rolling resistance, which reduces fuel economy. Regularly check your tire pressure and inflate them to the specified pressure listed on the driver’s side doorjamb.

Minimize idling, especially in cold weather. Modern diesel engines warm up quickly, so there’s no need to idle for extended periods. If you anticipate being stationary for more than a minute, turn off the engine to save fuel.

Consider removing any unnecessary weight from the vehicle. Extra weight reduces fuel economy, so remove any items that you don’t need to carry regularly, such as tools, camping gear, or aftermarket accessories when not in use.