We often talk about keeping storage tanks clean and dry to ensure quality fuel is available for your diesel and gasoline engines. It’s important because moisture in fuel causes all sorts of issues that can lead to unplanned downtime and equipment failure.

Ideally, we would like our fuels to be free of water, but small amounts will always be present. Diesel fuel will hold small amounts of water in suspension. “Suspended” water passes through with the fuel and is essentially “invisible” to the fuel system causing no damage.

However, when enough water is present that it can no longer be suspended, we get “free” water. Unchecked free water can lead to microbial growth, fuel line freeze-ups, biodegradation of fuel and fuel tank corrosion. Worse yet, water and associated contaminants can plug filters and ultimately cause more serious problems within the engine, such as fuel injector failures.

The most common source of water developing in a fuel tank is through condensation caused by a temperature differential between the inside and the outside of the tank. Condensation forms in the headspace and “sweats” down into the fuel. Reducing the temperature differentials by providing shade for the storage tank or painting it white can help diminish condensation. It helps reduce evaporation, too. For tanks on equipment, filling at the end of the day helps eliminate headspace and leads to less condensation as temperatures drop overnight.

We recommend the use of Hydrosorb® filters as they absorb small amounts of water as it passes through with the fuel. Plugged Hydrosorb filters can be a sign of water problems in your tank. Follow-up inspections and regular tank maintenance can help ensure that only dry fuel reaches your equipment.

Tanks should be inspected regularly to detect water and contamination before they cause other issues. Pull a sample from the bottom of your tank (not through the nozzle, as the fuel is already filtered), and check that it is still clear and bright. Hazy fuel is an indication that water is building up. Darker than normal color is an indication of microbial growth or fuel beginning to break down through oxidation. Particulates can be rust, dirt, pollen, etc. Remember that water and contamination problems can happen in transfer and equipment tanks, too.

If you suspect water problems in your fuel tank, call your FS Energy Specialist today.

Curt Dunafin serves as FS Energy Services manager.