TireSmoke.org

So either I forgot, or I never really knew this but:

The weight of a gallon of gasoline is about six pounds. There is a slight difference depending on the type of gasoline and its additives. Unlike water, which weighs about 8.4 pounds per gallon, gasoline is 25% lighter. Many people instinctively think that all liquids weigh the same as water, which is inaccurate.

Good information to have when calculating the weight of your vehicle.

-BP

Every time water goes to the bottom of the tank and the car stalls out I am reminded that water is heavier. However I did not realize it was that much lighter.