Where does the water in the fuel come from?
- Filling of bad diesel fuel. Sometimes, the diesel fuel used to fill up already contains water, as is the case with the tank bottoms of some ports, especially those that do not have a high level of traffic.
- A tank vent that allows air to enter during the season or a sand plug with a damaged rubber seal. It allows spray or rainwater to pass through the bridge.
- Condensation in the tank due to temperature differences. This phenomenon is amplified in regions with high daily temperature variations.
How is water annoying?
- An injector or the injection pump of a diesel engine are high-precision mechanical parts. Water in the diesel fuel can create rust spots that would permanently damage them.
- The water in the diesel fuel is stored at the bottom of the tank (the water is heavier than the fuel). It provides oxygen which promotes the development of micro-organisms that develop by feeding on diesel fuel. These bacteria create waste (excrement), emerge from brown filaments, which colonize the diesel fuel system, clog it and corrode it.
How to avoid water in the tank?
Start with prevention. Without water in the tank, there is no growth of bacteria and problems.
- Check the quality of the diesel fuel served at the pump. Avoid port tank bottoms. You can start your refuelling by filling a small transparent tank. Very quickly, if there is water, it settles to the bottom.
- Always leave your tank full, especially during the winter season. This reduces the amount of air in the tank, limiting condensation.
- Add an antibacterial treatment with each tank. The product, delivered with a pod, mixes with the fuel and prevents bacteria from living. The investment is really minimal compared to replacing an injection pump. Indeed, the treatment costs on average less than 2 cents per litre. We recommend Matt Chem Bact Fuel for its proven effectiveness.
Hence the interest of the settling filter...
Diesel engines are equipped with a filter at the inlet of the fuel system as standard. This filter only manages diesel impurities, not water. It is common to add a settling filter upstream between the tank and the engine. Operating on the principle of gravity (water is heavier than diesel), this device separates water from diesel. All that remains is to purge it regularly from below (without letting air into the circuit) to remove the water.
How to remove water from the tank?
Too late, your tank has taken on water. To get out of it, 2 curative solutions:
- Drain the tank completely. This solution often requires removing the tank (not always accessible) and rinsing it several times to properly remove all the sludge that has formed.
- Use a curative treatment in the form of an additive to be mixed with diesel fuel such as Matt Chem's Combifuel which emulsifies water (mixes water with diesel fuel in very fine drops that do not interfere with combustion) and dissolves the sludge. Waste is gradually eliminated. The curative treatment is a little more expensive than the preventive treatment, but remains very reasonable since it costs about 5 euro cents per litre.
What about the gas?
The problem of condensation and water formation are identical for both gasoline and diesel. The preventive treatments are the same (antibacterial to add to the tank) with products adapted for carburettors and injectors. Compared to diesel, the big difference is that petrol and its additives do not withstand long storage periods well. It is therefore not advisable to refuel before wintering to limit condensation. On the contrary, for the quality of the fuel, it is better to winterize the empty tank... No problem when it is a tank that you can easily unload and use the gasoline for your lawnmower, it is more delicate with a fixed tank.
Matt Chem, a specialist in the field, offers a treatment dedicated to gasoline engines. The treatment has an antibacterial function and absorbs water. 20 ml to treat 100 litres of petrol. Bottle of 125 ml. Recommended price in 2016: 25.74 euros including VAT.
