I got these tips in my email the other day and I thought I’d pass them along. Apparently, they’ve been circulating the net for some time already. I’ve cleaned them up for readability. I can’t tell you how true these tips are, but what the heck, they’re worth trying out. If it saves you a bit of cash in these outrageously gasoline-priced times, then more power to you.

1. Only buy or fill up your car or truck in the early morning when the ground temperature is still cold. Remember that all service stations have their storage tanks buried below ground. The colder the ground the more dense the gasoline, when it gets warmer gasoline expands, so buying in the afternoon or in the evening means your gallon is not exactly a gallon. In the petroleum business, the specific gravity and the temperature of the gasoline, diesel and jet fuel, ethanol and other petroleum products plays an important role. A one degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps.
2. When you’re filling up do not squeeze the trigger of the nozzle to fast mode. If you look you will see that the trigger has three three stages: low, middle, and high. You should be pumping on low speed, thereby minimizing the vapors that are created while you are pumping. All hoses at the pump have a vapor return. If you are pumping on the fast rate, some of the liquid that goes to your tank becomes vapor. Those vapors are being sucked back into the underground storage tank resulting in less gas for your money.
3. Fill up when your gas tank is HALF FULL or HALF EMPTY. The more gas you have in your tank the less air occupying its empty space. Gasoline evaporates faster than you can imagine. Gasoline storage tanks have an internal floating roof. This roof serves as zero clearance between the gas and the atmosphere, so it minimizes the evaporation.
4. If there is a gasoline truck pumping into the storage tanks when you stop to buy gas, DO NOT fill up. Most likely the gasoline is being stirred up as the gas is being delivered and you might pick up some of the dirt that normally settles on the bottom.

Hopefully this will help my fellow Southern Californian commuters who live a good 2-3 hours of their daily lives on the road.