Can 98 octane gasoline be mixed with 95 octane gasoline?

[DeLondyn]

98 octane gasoline should not be mixed with 95 octane gasoline, as it can cause the following hazards: 1. Affect the normal operation of the engine; 2. Lead to car noise, lack of power, and engine damage. Gasoline is a volatile and flammable hydrocarbon mixture liquid obtained from petroleum through distillation or cracking, and it can be used as fuel. The characteristics of gasoline are: 1. Volatility: It quickly vaporizes in the engine cylinder and forms a uniform combustible mixture with air; 2. Stability: The ability to resist oxidation under normal temperature and liquid phase conditions is called stability; 3. Anti-knock property: Refers to the ability of gasoline to resist detonation combustion under various usage conditions; 4. Corrosiveness: Sulfur compounds in gasoline can cause corrosion to objects.

[SavannahMarie]

I think mixing 98 and 95 octane gasoline is no big deal in the short term—it won’t immediately harm your car, as modern engines are quite tolerant. But in principle, 98 octane has a higher rating and better anti-knock properties, making it ideal for high-performance engines. Mixing them may lower the overall octane level, potentially causing slight knocking, increased fuel consumption, or reduced power under lower ratings. Doing this long-term could lead to carbon buildup or affect the emissions system. My car recommends 98 octane, but I occasionally mix in 95 when in a hurry—like when the fuel light comes on—and haven’t noticed any issues afterward. Still, for your car’s health and longevity, I strongly advise sticking to the manual’s recommended fuel grade and checking the fuel filter regularly. If budget is tight, using higher octane may save you money on repairs later. In short, mixing is fine in a pinch—just don’t make it a habit!

[VonManuel]

As an average car owner, I've driven several vehicles and tried mixing 98 and 95 octane gasoline. For instance, when 95 ran out, I'd top up with 98. The driving performance felt similar to normal, with no noticeable issues. However, I've heard that 98 octane fuel is purer, and mixing might lead to impurity buildup, potentially affecting spark plugs or fuel injectors. From my mechanic, I learned that occasional mixing is harmless, but long-term blending isn't advisable—low compression ratio engines may struggle, consuming more fuel and emitting some black smoke. Cost-wise, 95 is cheaper, but mixing saves little; higher-octane fuel actually cleans the engine better. I usually follow the manual's recommendation of using 98 octane to maintain optimal vehicle condition. Remember, mixing fuels is fine in emergencies, but don't make it a habit—engine protection is key.

[AdamFitz]

Can I just say: Mixing 98 and 95 octane gasoline is not dangerous, and the car can run normally. But it's not a good idea. 98 octane has a higher rating, and when mixed with 95, the fuel quality becomes inconsistent, which may cause slight vibrations or a small increase in fuel consumption. Especially if your car is specified for 98 octane, long-term mixing can accelerate wear. To be safe, follow the manual's recommended octane rating, and don't overdo it when mixing. Regular oil changes and maintenance are wiser.