Save Money at the Gas Pump with These Tips

We usually talk about health tips in this space, but with the cost of gas teetering at $4 a gallon I figure a blog on gas tips is a good stress reliever for all of us. So here are some tips from California petroleum expert John Hotaling on how to wring the last drop from each dollar you spend at the gas pump:

• Fill up early in the morning when the ground temperature is still cold. Gas stations store their gas in underground storage tanks, so cold ground means cold gas. Gas is at its densest when it's cold which means that you get more actual gas because the gas molecules are packed more tightly together. As temperatures rise during the day, gas molecules expand and each gallon you pump contains less actual gas. This is such a hot issue in the trucking industry where it can cost more than a thousand dollars to fill a semi tank that diesel pumps have temperature compensation safeguards. Those of us who drive regular cars and trucks have to provide our own safeguards. To get the most gas for your buck, fill your tank early in the morning.
• Pump gas at low speed when you fill your tank. Most gas pump nozzle triggers have three speeds: high, medium and low. Most of us squeeze the trigger tightly to fill the tank quickly on high speed. Pumping fast and furiously causes some of the gas you pump to turn into vapor in your gas tank. Since modern gas pumps are safety equipped with vapor returns, that vapor is sucked back out of your car and returned to the underground storage tank where it condenses back into gas. In effect, by pumping fast you pay for gas you don't keep. Pump your gas slowly on the low setting to minimize vapor creation and keep most of what you pay for.
• Fill up when your gas gauge hits the half full point. Gas evaporates unbelievably quickly. As your vehicle uses gas, the gas is replaced by air in your gas tank. The gas in the tank starts to evaporate into the air. By keeping your tank full, you keep air from building up in the tank and thus minimize evaporation.
• Don't fill up if the station's tanks are being filled. If you arrive at the gas station and the tanker truck is there pumping gas into the underground storage tanks, buy your gas somewhere else that morning. The process of filling the storage tanks stirs up dirt and debris that normally settles at the bottom of the tanks, swirling it through the gas. It may take a couple of hours for all that debris to settle back onto the bottom of the tank. You don't want that goop getting into your car's gas tank where it can filter into your engine and cause trouble. So if you see a tanker at your normal gas station, cruise on down the street and visit the competition.