Motormouth: Keeping hybrid gas fresh

Q: I am considering a plug-in hybrid because I work close to home and usually drive no more than 15 miles a day. So theoretically I could go days or weeks or maybe even months without using the internal combustion engine. My father always was a fan of periodically taking out an infrequently used car to “stir the tanks,” so to speak. So, if the gas engine on my hybrid is not used for an extended time, does it need some type of additive or other precautions?

A: The fuel should stay fresh for six months or more. If you want to ensure it stays fresh longer than that, add a fuel stabilizer such as StaBil or Sea Foam when you gas up. Or follow your dad’s advice and take the vehicle out for a periodic spin.

Q: I’ve always put regular gas in my vehicles even if premium was recommended by the manufacturer and never experienced any issues. I currently own a vehicle that has a 3.0-liter turbo V-6 engine, and the manufacturer is recommending premium. I’d appreciate your opinion regarding what’s best.

A: That is almost a trick question. One answer is that premium gas is best for overall performance. On the other side, regular gas is best for your pocketbook. I prefer to use premium gas with turbocharged engines because I am a spirited driver. Engines are equipped with knock sensors that alert the engine control computer to detune the engine when using regular gas, reducing performance, until the knock stops. You must choose what’s best for you.

Q: We have a 2019 Subaru and recently moved from Michigan where regular 87 octane unleaded typically does not contain ethanol. Here in Minnesota and surrounding states, the norm is 10% ethanol. I remember back in the day when ethanol was introduced, the old shadetree mechanics claimed it could eat away at fuel lines and gaskets. Are there any concerns with using the 10% ethanol, or any benefits? I have not noticed any performance issues.

A: Back in the day, fuel systems, gaskets and such were made using materials that didn’t tolerate alcohol very well. That day is long gone. You will not encounter any engine issues, but you may encounter a slight drop in fuel economy with ethanol-laced gasoline.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician. His writing has appeared in automotive trade publications, Consumer Guide and Consumers Digest. Send automotive questions along with name and town to motormouth.tribune@gmail.com.