Can I switch to 95 octane after always using 98 octane?
2 Answers
You can switch from 98 octane gasoline to 95 octane gasoline as long as your vehicle allows the use of 95 octane. Different grades of gasoline do not undergo chemical reactions, so they can be mixed. Different octane ratings indicate varying levels of stability, with higher octane gasoline offering better stability. Different grades of gasoline have different octane ratings. The higher the grade, the higher the octane rating, and the better the gasoline's anti-knock performance. Knocking is an abnormal combustion phenomenon in the engine. When the piston is in the compression stroke, moving upward to compress the combustible mixture, the temperature and pressure of the mixture increase. If the gasoline's anti-knock performance is poor, the combustible mixture may ignite before the spark plug fires, causing knocking. The burning mixture pushes the piston downward while it's moving upward, leading to reduced engine power, increased fuel consumption, and potential engine damage.
I used to fill up with 98-octane gasoline for convenience, thinking it had better anti-knock properties. Later, when fuel prices soared, I switched to 95-octane to save money. Unexpectedly, the engine started making a slight knocking sound, like metal tapping. After checking the manual, I realized my car is recommended for high-octane fuel, and using lower grades could cause knocking and engine damage. I immediately consulted my mechanic friend, who said occasional use is fine, but long-term use might affect engine lifespan. Now I strictly follow the manual's recommendation. For regular sedans, using 95-octane to save money is perfectly fine—no need to blindly opt for higher grades. The key is understanding your car's specific requirements and not taking risks just to save a few bucks.
