What to Do If 95 and 92 Gasoline Are Mixed?
2 Answers
Mixing 95 and 92 gasoline occasionally once or twice has little impact. Short-term mixing of different gasoline grades generally does not require special vehicle maintenance. However, long-term mixing of different gasoline grades will affect the service life of the car's ignition system, fuel injectors, and spark plugs, advancing the vehicle's overhaul time. The gasoline grade is the ratio of the actual gasoline's anti-knock performance to that of standard gasoline. The higher the grade, the stronger the anti-knock performance. Standard gasoline is composed of isooctane and n-heptane. Isooctane has good anti-knock performance, and its octane number is defined as 100. N-heptane has poor anti-knock performance and is prone to knocking in gasoline engines, so its octane number is defined as 0. If the gasoline grade is 90, it means that the gasoline contains 90% isooctane and 10% n-heptane, which has the same anti-knock performance as standard gasoline.
When I was younger, I made a similar mistake while driving—I absentmindedly mixed 95 and 92 octane gasoline in the fuel tank. At first, I panicked, worrying about engine knocking and potential damage, since 95 octane is designed for high-performance engines, and mixing it with lower-octane 92 would reduce the overall octane rating. However, in practice, the car ran without major issues. I immediately went to the gas station to fill up with 95 octane fuel to dilute the mixture and raise the average octane level, reducing the risk of knocking. After that, I drove gently to finish that tank, and the engine performed as stably as usual. The experience taught me that an occasional mix-up is harmless, but don’t make it a habit—especially for cars that require 95 octane, as long-term use could lead to cumulative damage or increased fuel consumption. My advice to you: If you add the wrong fuel, quickly top it off with higher-octane gasoline, and monitor for any unusual noises or sluggish acceleration while driving. If everything seems normal, just drive until the tank is empty; otherwise, get a professional inspection—safety first. Preventing mistakes is simple: Next time at the gas station, double-check the labels and don’t be careless again.
