Fuel: Testing and Inspection

Measuring the ethanol content

The method works for gasoline-ethanol fuel.

Note! First read the safety instructions for handling fuel.

Drain the fuel carefully from the vehicle.

Note! The fuel should be drained from the fuel distribution pipe and not from the fuel filling pipe/tank.




Mix equal parts of fuel and water in a graduated, transparent container. Let stand for at least 5 minutes. The ethanol dissolves in the water and the mixture separates into layers. Gasoline is the lightest and ends up at the top.
Read off the number of graduation steps of gasoline and compare to the number of graduation steps of fuel that has been added. Best accuracy is achieved with a long-narrow measuring glass. Suitable design of version measuring glass is total volume of 500 ml with markings for every 5 ml, or total volume of 1,000 ml with markings for every 10 ml.

Caution! Measuring has to be accurate.

Example: Mix 500 ml fuel with approx. equal parts water. After the ethanol has dissolved we can assume that the measured amount of gasoline is 120 ml.
Gasoline content is then calculated to: 120 ml/500 ml = 0.24 = 24%
This, ethanol content is: 100%-24% = 76%

Hint: When the ethanol dissolves in the water the fluids' total volume is reduced. To facilitate read-off you can fill the container with more water. Note that this does not affect the calculations above, since this takes place in relation to the amount of added fuel.