As with any hot topic there are tons of myths about gas and your car’s mileage. Let’s take a look at a few of the more common myths circulating today.
Myth #1: Buy gas in the morning when the gas is cooler, thus denser.
Gasoline is stored in underground tanks, which remain at a fairly constant temperature. I have personally reviewed the tank readings at my local gas station to confirm this fact. It’s like a cave, which stays at a constant temperature all year long due to it’s distance from the surface of the earth. The only factor that comes into play, is when the gasoline is delivered to the tank. When gasoline is transported in trucks, it will expand with heat. If you buy your gas right after the tank is filled, you will receive warmer gas, but I would not stake out your local gas station to find out when the gas truck delivers.
Myth #2: Driving with the windows down at highway speeds without A/C is better than windows up with the A/C on.
When at highway speeds, keep your windows up. On most vehicles, having the windows open at highway speeds will create extra drag and cost you gas. If it’s a hot day, running the A/C is a necessary evil, and will cost you gas mileage, but the loss is about equal to keeping the windows down on most cars. When driving under 45mph, keeping the windows open and A/C off will be more economical because drag from having the windows is not in effect at the lower speeds.
Myth #3: Keep your engine running if you are making a quick stop at the store, it takes more gas to start your engine than to leave it running for a few minutes.
This myth is not true, starting an engine takes very little extra fuel, and it is always better to turn the engine off.
Like anything in life, cheaper is not always better. When it comes to buying gas there are a few things to remember.
Name brand gasonline generally has more detergents, which help your engine run cleaner and more efficiently. I personally use Texaco due to some personal experiences and the fact that I used to work at a Texaco station in high school and college. At the time, the regular gasoline did not have the same additives as the plus and supreme grade. I switched from regular to plus grade, and got better gas mileage. I was driving a 1979 Mustang at the time with a 4 cyl. engine and went from 18 to 20 mpg just by switching grades of gas.
To find the lowest prices, there are websites online, which post almost real-time gas prices across the country. I would also shop at gas stations, which have competition, which will drive prices down. So the more gas stations in the area, the better the price.
When you are at the gas pump, start the pump and then take a walk around your vehicle. You should check all 4 tires for any signs of low air pressure. In all but the higher performance tires, you can see the sidewall of the tire bulge when air pressure drops. Once per month I would check the tires with a quality tire gauge to be safe. Low tire pressure can create more rolling resistance and will hurt your gas mileage. If you are not a good judge of tire pressure by looking at the tires, consider a cool new product on the market that replaces your valve stem cap. It shows green when your tires are at the proper pressure, and red when they are low on air.
While I know a lot about cars, I don't know a lot about YOUR CAR! If you are looking for vehicle specific instructions, an online repair manual is the ticket. I recommend Alldata or Mitchell1, but also have some tips to get a free repair manual which while not as complete, can work in a pinch.
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Posted: 2nd June 2006 | Author: Kevin Schappell | Category: Car Care, Fuel