Not all fuel octanes are made the same

Every week, we take your questions about what is going on under the hood of your vehicle and pose them to a knowledgeable mechanic in the Greater Toronto Area. In today’s column, we learn more about wheel alignments and whether you need to use a certain grade of fuel in a luxury vehicle.

Dear Ask a Mechanic,

I own a 2018 Kia Sportage. When I change my tires to winter ones, I notice a difference while driving. When I change back to my summer tires my dealer includes a wheel alignment and a wheel balancing. Is it necessary to have my wheels aligned every time I change to summer tires? – Getting Aligned

The short answer from Mohammad Hajiani, owner of M & M Auto Body Repair & Collision Centre in Scarborough, is no. “Personally, I think it’s a waste of money,” said Hajiani, a Red Seal-certified car technician with eight years of experience. He acknowledged his opinion is different from what is included in vehicle maintenance manuals. Those state that every time a driver does something that effects the tilt of their tires, such as driving over a pothole or rubbing against a curb, it alters their alignment. Getting your tires aligned and balanced extends their life, but it’s not something that needs to be done very often, Hajiani said. Unless you feel your tires are slanting, or it feels like something has changed mechanical after your wheels are changed, he said a seasonal alignment is not necessary.

Dear Ask a Mechanic,

I drive a luxury car and was always told I need to use a higher-octane fuel. Recently I have seen my income decrease and I want to save money where I can. Can I use a lower octane, and lower cost, fuel or is this going to cause other problems I will need to pay for later? – Fuel Efficient

You can absolutely use a lower octane fuel to save some money, Hajiani said. “Going to a lower grade will not kill it,” he said. But this advice comes with a few caveats. A fuel’s octane level measures its stability, with premium octane possessing a higher rate of burn that helps keep the engine clean. If you switch from the highest octane to the second highest when you fill up, it won’t damage your engine, but you won’t get the same performance expected from a luxury vehicle. Using the lowest octane level of fuel may not be your best option, Hajiani said, as it will eventually clog the filter that cleanses any containments from the gas before it reaches your car’s engine.