Used cooking oil may offer a cheaper alternative to diesel, according to an experiment by Russian automotive workshop Garage 54, which tested sunflower oil and used cooking oil in an old-school Nissan Terrano, also known as the Pathfinder in the U.S.
Diesel Prices Reach Record High
AAA recorded its highest-ever national average diesel price at $6.5276 a gallon on September 22, 2026. Rising diesel costs are affecting not only motorists but also farmers who depend heavily on diesel-powered equipment and work vehicles.
The higher prices have increased interest in alternatives such as electric vehicles, but Garage 54 explored another option that can be found closer to home: cooking oil.
The Russian workshop, known for extreme automotive experiments such as converting a Subaru boxer engine into an inline-four, tested the alternative fuel in an old Nissan Terrano. The experiment came as diesel prices in states including California, Washington and Hawaii climbed above $7 a gallon.
Garage 54 Tests Sunflower and Used Cooking Oil
During the initial test, the sunflower oil-fed Terrano performed well, with the presenter noting that the SUV did not make much rumbling noise.
Because the vehicle was consuming a large amount of oil, the workshop switched to an even cheaper option: used cooking oil that had previously been used to deep-fry French fries and chicken.
Online listings showed that a liter of used sunflower oil cost 25 to 35 Russian rubles, or about $1.12 to $1.57 per gallon at current exchange rates.
The following day, however, the Terrano struggled to start because the oil had thickened in the cold temperature. After the glow plugs were manually engaged to heat the system, the SUV returned to the road for additional testing against diesel.
Used Cooking Oil Delivers Similar Test Results
The first comparison was a zero-to-80-km/h (zero-to-49.7-mph) sprint. The diesel-powered Terrano completed the run in 24.08 seconds, making it only about 0.3 seconds faster than the alternative.
The next test measured efficiency using one liter of each fuel. The results were again similar, with the Terrano traveling 10.7 km (6.6 miles) on diesel, just 0.7 km (0.43 miles) farther than it traveled using used cooking oil.
Why Cooking Oil Is Not Recommended for Modern Diesels
Despite the test results, cooking oil is not recommended for modern common-rail diesel engines, including modern Ford Power Stroke and Chevrolet Duramax applications.
Cooking oil is much more viscous than diesel, making it better suited to older mechanical injection systems, which can be more tolerant than common-rail systems that operate with extremely high fuel pressures and precisely controlled injectors.
Using straight used cooking oil can also place additional strain on the fuel pump and injectors and contribute to carbon buildup over time.
Still, with fuel prices rising amid ongoing tensions in the Middle East, the experiment shows why used cooking oil can appear to be an appealing alternative to diesel in older diesel powertrains.
