Carlos Pérez, Spain's best mechanic: "Filling up with 98-octane gasoline instead of 95-octane isn't worth it; the important thing is to avoid low-cost fuel, which can cause breakdowns in the long run."

Stopping at a gas station to refuel is a routine action that thousands of drivers do every day. Regardless of whether it's better to fill up in the morning or fill up early in the week to save a few cents, the underlying question remains the same: is it better to use 98-octane gasoline if the car runs on 95-octane?

Carlos Pérez (Valladolid, 1978), chosen as Spain's best mechanic in 2025 by La Comunidad del Motor , is very clear. "Most cars that run on gasoline are designed to run on 95 octane, although they can also use 98. But in my opinion, it's not worth the small financial effort, since what you gain on one side you lose on the other," he says in a telephone interview with La Vanguardia's Moveo channel.

The Gabilondo Automobiles professional explains that, although 98-octane gasoline can provide greater range , this improvement isn't due to the higher octane rating, but rather to the fact that this type of fuel typically contains a higher percentage of additives that help keep the engine cleaner and in better condition. "However, those extra miles you can get with 98-octane gasoline are offset by the higher price you pay at the pump, so in the end, it doesn't represent a real savings for your wallet."

Regarding the idea of ​​alternating between 95 and 98-liter tanks to get the most out of both fuels, Pérez doesn't consider it necessary or particularly beneficial. "I don't recommend alternating, because it offers no real benefits and complicates fuel consumption without the engine even noticing."

Furthermore, Pérez points out that the engine only benefits from higher octane ratings when designed for it, generally in high-performance cars or those with high-compression engines . In other vehicles, the regular use of 98-octane gasoline offers no significant benefits. Therefore, he insists that "the most important thing is to always follow the manufacturer's recommendations and choose quality fuels, without being misled by false beliefs or marketing."

In this regard, Javier Sendín's successor as Spain's best mechanic does recommend that users use quality gasoline in their vehicles. "Although all gasoline ultimately comes from the same wholesale suppliers, the differences lie in the additives that each company incorporates. These additives are what help keep the fuel system clean and prevent the buildup of residues in the engine, which can affect the vehicle's performance and durability."

For this reason, Pérez advises avoiding low-cost gas stations , which, while seemingly cheaper at first glance, often have lower levels of these protective additives. "The price may be tempting, but in the long run, using lower-quality fuels can cause breakdowns and increased engine wear, with the associated cost in repairs," says this renowned mechanic.

For him, it's best to opt for well-known brands because, even if they cost a little more, they prevent problems in the long run and help the engine last longer in good condition, especially in cars with more mileage or older cars. "Ultimately, good fuel is an investment in peace of mind and maintenance," says Pérez.