What happens if you mix 95 and 98 octane gasoline?

When refueling our vehicle, choosing the right type of fuel is crucial. But what if different octane grades of gasoline are mixed in your tank?

It is available at gas stations unleaded petrol and 95 and 98 octane, two options that have different octane numbers but one thing in common: the absence of tetraethyl lead. Apparently, mixing them into our car’s gas tank is not as destructive as putting for example diesel in a vehicle with a gasoline engine. But it can affect the operation of our car. Let’s see how.

The difference in octane number, also determines the fuel’s ability to resist pre-ignition when compressed in the engine cylinder. The higher the octane number, the higher the resistance, allowing the engine to run more efficiently.

Additionally, higher octane fuel generally contains less sulfur, which benefits the engine catalyst longevityreduces the fuel consumption and improves overall engine performance.

Mixing 95 and 98 octane gasoline it is not directly harmful but can have long-term effects on the engine, especially if the vehicle is designed to use only one of the two types. If a car designed for 98 octane gasoline is constantly getting 95, it can present performance reduction and increasing engine wear due to less optimal combustion.

On the other hand, in a vehicle that requires 95 octane, using 98 octane gasoline provides no tangible benefits in terms of performance or fuel efficiency, as the engine is not designed to take advantage of additional resistance in the ignition offered by the higher octane rating.

As in any other field of operation of the car, but especially here, it is important to follow the factory recommendations about octanes. These are usually available in the owner’s manual, on a sticker on the fuel filler cap or on the inside of the driver’s door.

If the manual specifies 98 octane gasoline, it is best to follow this recommendation to optimize engine performance and life. As we said, there may be no immediate danger to your car’s engine, but the systematic choice of lower octane fuel can in the long run lead to functional problems and costly damages.

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