A mistake that many drivers make when filling their gas tank is to overfill it by topping it off. When the gas pump nozzle clicks off automatically,do you keep pumping? Are you trying to add as much gas as you can possibly stuff into your tank? Do you pump more gas after the automatic shutoff to round your total to nearest full dollar amount? In either case this is a bad habit that is most likely costing you a lot of money and is contributing to air pollution.

Most gas stations are equipped with pumps that have vapor recovery systems to recover gas vapors keeping those vapors from getting into the air. If you top off your tank it will cause you to pay for gas that is drawn back into the gas station’s vapor recovery system.

The extra gas you are trying to stuff into your tank may be drawn into the vapor recovery system back into the station’s tanks. In that case you are paying for gas that is not going into your car but is going back into the gas station’s tanks. The effect of this, of course, is to raise your cost of gas.

When you overfill your tank there is a good chance that gasoline will evaporate or will be spilled. Both of these costs you money for gas that is not getting into your car. That is not good for your wallet.

There are more bad things that can happen when topping off your gas tank. Gasoline expands as it gets warmer. This is certainly important in the summer or in climates with warm weather. Gas in the station’s underground tanks will be cooler than the air. As the gas in your tank warms up it expands. As the gasoline expands it needs more room.

If you top off your tank, then there is no extra room for the gas to expand. Where does the expanding gas go? It may find it’s way into your vehicle’s vapor collection system. That could easily foul this system causing it to malfunction. If this happens your vehicle will run poorly and have high gas emissions.

The fuel that expands is lost gasoline that you have paid for. You paid for gas that you are not able to use. The result: your cost of gasoline goes up. But that is not the end of your increased costs! If the expanding fuel ends up in your car’s vapor collection system it will negatively affect the system. If that occurs your vehicle will become much less efficient.

A vehicle that runs inefficiently burns more fuel which translates into spending more money on gas. That is a double hit in the wallet, once for the fuel that is lost directly and second for the additional gas your vehicle uses because it is running inefficiently.

Gas vapors are a major factor in adding toxic pollutants such as benzene to the air. This contributes to bad ozone days. Gas vapors are bad for your health and harmful to breathe. When you top off your tank you will end up with vapors released into the air. When this happens you are breathing in toxic fumes.

When you next fill your truck or car, when the pump automatically stops don’t add any more fuel, your tank should be full enough. Don’t top it off, don’t overfill it. Not only will you be saving money but also helping your own health and helping the environment!