Money-Saving Gas Tips
Gas prices suck…a lot. That is all. While perusing my local car forum, a member who has been working for the petroleum industry for 31 years posted some neat tips and interesting facts about pumping gas and saving money.
Tip 1: Buy in the early morning
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….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 1-degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps.
Tip 2: Slow pump to avoid vapors
When you’re filling up do not squeeze the trigger of the nozzle to a fast mode. If you look you will see that the trigger has three (3) stages: low, middle, and high. In slow mode 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 other liquid that goes to your tank becomes vapor. Those vapors are being sucked up and back into the underground storage tank so you’re getting less worth for your money.
Tip 3: Fill-up on half full or half empty
One of the most important tips is to fill up when your gas tank is HALF FULL or HALF EMPTY. The reason for this is, 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. Unlike service stations, here where I work, every truck that we load is temperature compensated so that every gallon is actually the exact amount.
You can read the rest of the tips and full forum post here.

Comment by K Owusu on 4 April 2008:
Great post. Will keep this in mind.
Comment by coolermaster on 27 May 2008:
With extremely high gas prices straining consumers pockets in recent months, it is only natural for people to wonder where all the money they pay at the pump goes..