What to Do If 92 and 95 Gasoline Are Mixed?
2 Answers
Mixing 92 and 95 gasoline once or twice has little impact on the car. However, do not blindly use higher or lower octane gasoline, as this can easily lead to carbon deposits. It is best to follow the manufacturer's recommended gasoline octane rating. Below are the differences between 92 and 95 gasoline: 1. Different n-heptane content: 95 gasoline contains 5% n-heptane, while 92 gasoline contains 8%. 2. Different isooctane content: 95 gasoline contains 95% isooctane, while 92 gasoline contains 92%. 3. Different anti-knock properties: Different gasoline octane ratings represent different anti-knock properties. The higher the octane rating, the better the anti-knock performance. 95 gasoline has better anti-knock performance than 92 gasoline.
I recently encountered the same issue—filled half a tank with 92 octane before realizing I should have used 95. I specifically consulted a 4S店 technician afterward, who said occasional mixing has minimal impact. The key factor is the car's compression ratio: if a car designed for 92 octane gets 95, it may lead to slightly more incomplete combustion and carbon buildup. However, mixing 92 into a high-compression-ratio engine is risky, increasing the likelihood of engine knocking. Modern vehicles generally feature adaptive ignition correction, allowing the ECU to learn and adjust after mixed fueling. Short-term advice is to use this tank until the fuel light comes on before refilling with the correct grade—avoid draining the tank unless persistent engine knocking occurs. Long-term mixed use will definitely harm the engine, especially in turbocharged models.
