When water gets into a fuel tank it can create problems. If it gets into the fuel line, it will clog up the engine. Water gets into the fuel tank through several ways: through contaminated fuel, through water condensing in a fuel tank when it is humid, and when rain seeps through a leaking fuel cap. You can save yourself a lot of headaches by learning how to detect when water is in your vehicle's fuel.
Fill up the car with fuel. Wait two hours.
Siphon off a small amount (about 2 fluid oz.) of the contents of the tank into the glass using the plastic tube. This should be done from the bottom of the fuel tank as water is denser than either gasoline or diesel.
Siphon off a small amount (about 2 fluid oz.) of the fuel from upper layer of the fuel tank into the glass.
Check the glasses to see if there is a distinct separation of the liquid when you hold up the glass to eye level. If there is, there is contamination as this denotes a separation of water and fuel. If the contents are uniform, there is no contamination.
