A Costly Mistake at The Gas Pump You Can Avoid!

by : Scott Siegel

When the gas pump nozzle clicks off, do you stop or do you keep pumping?

  • Are you trying to add more gas your tank after the shutoff trying to stuff as much in as possible?
  • Are you pumping more gas after the shutoff to round your total cost to the nearest full dollar amount?

If either of these scenarios are true, or if any other reason causes you to top off your tank you have developed a bad habit that is costing you money and is contributing to air pollution.

The costly mistake many drivers make when filling their car with gas is to overfill it by topping it off.

  • 1) 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. 

  • 2) The extra gas you are trying pump may be drawn back through the vapor recovery system into the station's tanks. Then in essence you are paying for fuel that is not going into your tank but is going into the gas station's tanks. This, of course, raises your cost of gas. 
  • 3) When you overfill your gas tank it is almost a certainty that gasoline will evaporate or will be spilled. If either of these or both of these occur it means buying gas that is not getting into your car. That has to hurt you in the wallet. 

Gas expands as it warms up.
This is certainly something to keep in mind in the summer or in areas with warm weather. Gas in underground tanks will be cooler than the air as the ground insulates it from the heat. The fuel in your tank gets warmer it expands. As the fuel expands it has to have more room. 

  • 1) You just paid for gas that evaporated away
    If you overfill your car, there is no room for the fuel to expand. As the gas expands it has to go somewhere. it goes out via the vapour collection system of your car. You just paid for gas that evaporated away
  • 2) Access vapour will make your vehicle inefficient
    Once the expanding fuel ends up in your car's vapor collection system it will negatively affect the system. When this occurs your vehicle will become much less efficient and this may foul the vapor system causing it to malfunction. 
  • 3) An inefficiently vehicle burns more fuel
    This means you now need to spend 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. 

The next time you stop to fill your vehicle, when the pump stops don't try to add any more gas, your tank should be quite full. Don't overfill it! Don't top it off! You will save yourself fuel and money.