Can I add 95 gasoline when there is still a little 92 left in the car?
3 Answers
You can add 95 gasoline when there is still a little 92 left in the car. It has little impact on the car and the engine itself, but due to the insufficiently high compression ratio design, it cannot fully utilize the characteristics of 95 gasoline, leading to stagnation and increased fuel consumption. The differences between 92 gasoline and 95 gasoline are as follows: Different anti-knock properties: The gasoline grade represents the anti-knock property, and the higher the grade, the better the anti-knock ability. Different isooctane content: 92 gasoline is composed of 92% isooctane and 8% n-heptane, while 95 gasoline is composed of 95% isooctane and 5% n-heptane. The reason why 95 gasoline is slightly more expensive is the higher proportion of isooctane. Different prices: A tank of 95 gasoline is slightly more expensive than a tank of 92 gasoline. Effects of adding high-grade gasoline to low-grade cars: Low-compression ratio engines are mostly installed in low-end cars, and most of them use 92# gasoline. If 95 or 98 gasoline is added, the higher the grade of gasoline, the better the stability, making it at least difficult for the engine to malfunction due to knocking. However, adding high-grade gasoline to a low-compression ratio engine will result in incomplete combustion of the fuel, wasting power and making it more prone to carbon deposits. If some car owners are curious about this, it's okay to try adding it a few times occasionally.
Having driven for decades, I've seen many similar situations. It's definitely okay to add 95 octane gasoline when there's a little 92 octane left in the tank—engines aren't as fragile as people think. The difference between 92 and 95 octane gasoline lies in their anti-knock capabilities. When mixed, the octane rating averages out somewhere in between. Modern engine computers automatically adjust ignition timing to adapt to these changes, preventing knocking or damage. Back when I was young and drove beaters, I often mixed different octane grades, and the cars ran just fine. When there's only a small amount of fuel left, adding 95 octane might even make the engine run smoother—though that's mostly psychological. From a cost perspective, 95 octane is more expensive, but since the remaining fuel is a small proportion, the total expense is roughly the same. Safety-wise, there's nothing to worry about; no need to fear sudden breakdowns—just drive to the station and fill up. For the long term, it's best to follow the manual's recommendation, but mixing once in a while is completely harmless.
Having worked in a repair shop for years, I've encountered too many similar issues. Straight answer: yes, you can mix them, no problem. Both 92 and 95 are essentially gasoline—they don't react chemically when mixed. The octane rating will average out, and the engine control module adjusts parameters automatically to prevent damage. If your manual states '92 or above,' this approach works well; if it specifies 92 only, no need to spend extra on 95, but topping up with 95 when low on 92 can actually improve knock resistance. Cost-wise, 95 is slightly pricier per liter, but the small remaining volume won't significantly impact expenses. Don't worry about part damage or corrosion—mixing is safe unless you drive a specially tuned race car. Just avoid frequent mixing during routine driving.
