Is it a problem to add 98 gasoline when 95 gasoline is not used up?
2 Answers
It is problematic to add 98 gasoline when 95 gasoline is not used up. Below is the relevant introduction about gasoline: Avoid mixing gasoline: For the new gasoline standard, there are some doubts and concerns, but you can also add 95 gasoline. However, because the components of different gasoline grades are different, it is best to avoid mixing gasoline of different grades. Different anti-knock indexes: Gasoline is a mixture. The gasoline grades we usually encounter refer to different anti-knock indexes (i.e., octane numbers) of gasoline. Strictly speaking, 92 gasoline and 95 gasoline cannot be mixed. However, their chemical compositions and other aspects are relatively similar, and they have strong anti-knock properties. Generally, mixing them will not cause significant problems, but to ensure vehicle safety, it is best to use them separately.
As a long-time driver, I often encounter this situation of mixing fuel grades. Honestly, there's no major issue with adding 98-octane fuel when there's still some 95-octane left in the tank. The fuel grade represents the octane rating, and 98-octane has slightly better anti-knock properties than 95-octane. The engine's computer system will automatically adjust the fuel injection and ignition timing to adapt to different grades. This means you don't need to worry about engine damage or knocking - the car will still run smoothly. Of course, it's recommended to use the manufacturer's recommended fuel grade whenever possible. For example, if your car is designed for 95-octane, don't switch too often to avoid potential carbon buildup or minor long-term effects from frequent mixing. But mixing occasionally once or twice is completely normal. I've done it several times myself without any abnormal engine response, and actually felt slightly smoother acceleration. In short, don't overthink this - modern cars are quite smart.
