What happens if you add 92 octane fuel to a car that requires 95 octane?
2 Answers
Short-term use or accidental mixing of different octane fuels has minimal impact and generally does not require special vehicle maintenance. However, if a car that normally uses 95 octane fuel is filled with 92 octane, it is recommended to use up the current fuel before refilling with 95 octane. Below are additional details: 1. Composition: 92 octane fuel contains 92% isooctane and 8% n-heptane, while 95 octane fuel contains 95% isooctane and 5% n-heptane. The higher the proportion of isooctane, the better the anti-knock performance. 2. Avoid prolonged mixing: Gasoline is a mixture, and while occasional mixing or accidental use poses no major issues, prolonged mixing should be avoided. To ensure vehicle safety and performance, it is best to clearly distinguish and use the correct octane rating. Otherwise, it can directly affect the engine, shorten the lifespan of spark plugs, and increase tailpipe emissions.
I used to be confused about this issue too. Back then, I was in line at the gas station and casually filled up with 92 octane. On the way home, I immediately noticed something was wrong—the engine was humming loudly, and there was a constant knocking sound when accelerating. It turns out the biggest difference between 95 and 92 is the octane rating. 92 has poorer anti-knock properties, making the engine prone to knocking under high compression ratios. Using one tank of it occasionally isn’t a big problem, but definitely avoid flooring the accelerator, or the piston rings and spark plugs might quit early. That time, I immediately topped up with half a tank of 95 octane to balance it out and drove as gently as a bicycle until the next refill. Now, I always double-check the octane rating three times before filling up.
