Q: I have a 2011 Chevy pickup with standard issue 17-inch tires/wheels. I need new tires. I'm thinking about going up to 18-inch with new wheels, too. Would this increase or decrease gas mileage?
A: You can go with 18-inch wheels and tires, known as a plus-one upgrade. But the overall diameter must be the same as your original tires. Otherwise, your speedometer will report the wrong speed. The wrong diameter also will affect the anti-lock brake system and possibly the stability control system. To avoid these issues, you need tires with a lower profile. Plus-one or plus-two tires might improve the look of your truck, but will do nothing to your fuel economy.
Gas guzzler
Q: You advised readers to follow the owner's manual in choosing a grade of gas. Does that advice still hold if the manual says regular is fine but, for reasons long forgotten, the owner has been pumping mid-grade over a car's entire 17-year life? Has that caused any harm?
A: The only harm you have done is to your wallet.
Finnicky fan
Q: My 2016 Ford Explorer had a recall performed for the high-speed cooling fan motor relay. Now the fan turns on very loudly every (approximately) 30 seconds at idle when the A/C is on. It is so loud that I turn off the A/C when placing an order at a drive-thru. The service adviser at the dealership listened to it and told me that this is normal when it's hot out. Is this how it should have sounded all along?
A: If it didn't come from the factory with that noise, it should not make that noise now. I wonder if they changed the fan along with the relay. A fan with the wrong blade pitch could be the culprit.
A gate glitch
Q: We have a 2022 Tesla Model X. We have an electric gate opener, but we cannot program the Tesla to open it. We had no problem programming it to open our garage door. We followed the owner's manual instructions, but no luck. Is there some way to do this?
A: An older gate opener might lack the technology. If you have used a handheld opener in the past, you might have to continue using it. Otherwise, you might have to upgrade the gate opener itself.
