3 tell-tale signs that your fuel is contaminated

Thu, December 12, 2019 - 11:03:00

Contaminated Fuel

Fuel contamination is a phrase that’s been bandied around for some time now, but it’s an issue that’s not going away! If you store diesel on site, then it’s important to know how to tell if you have a problem and what you can do about it. But first, how does your fuel even get contaminated?...

The increasing bio-content in today’s diesel means that the fuel in storage tanks often contains small, but problematic water levels that sink to the bottom. As the area between the water and the fuel is the perfect environment for microbial growth, what is known as “diesel bugs” begin to develop. When these bugs are not dealt with, they can create a nasty sludge. It is this “biofilm” that can block filters, damage pumps and get sucked into machinery causing equipment failure, downtime and costly repairs.

For this very reason, it is vital that tank owners can spot the tell-tale signs that their fuel might be contaminated. Do you know what to look for?


1. The appearance of your fuel 

Diesel should usually appear clear and bright. If it doesn’t then this could be an indication that water is present within the fuel. Once water in a tank becomes emulsified, droplets of water will form which gives the fuel a slightly cloudy or even milky appearance. If left, this water content causes the nasty microbial sludge to grow that blocks filters and damages vehicles. When checking the appearance of your fuel, it is best to take a sample from the bottom of the tank as well as the top, as this is where the layer of diesel bug sludge forms. 


2. Filters and equipment problems 

The first thing you are likely to notice when contamination becomes an issue is your fuel filters blocking more quickly than normal. When changing your filter, check for traces of sludge that indicate you have a problem with water contamination. 

If contaminated fuel gets into your vehicle, then you may start experiencing issues such as power loss, spluttering and involuntary speed changes. These are signs that the fuel isn’t burning as it should do, perhaps because the sludge is restricting fuel flow to the engine. 

3. Erosion of your tank

If diesel bug contamination is not dealt with and left to worsen, it will eventually start to eat away at the tank itself. It is standard practice to check your tank for rust, cracks and holes – and if you can visibly see this, it may be a sign of a severe contamination problem that needs to be dealt with. Once erosion begins, your tank could be at risk of leaking and causing an oil spill. 


What to do if you suspect your fuel is contaminated?

If you’re experiencing any of the above tell-tale signs that your diesel may be contaminated with diesel bugs, then it is important that you act immediately to prevent further costly issues:

  • Keep stock of spare filter elements on site to ensure you can quickly replace them when they get full.
  • If your existing fuel is salvageable, get it professionally polished before you put any more into your vehicles and equipment and cause damage.
  • Have your tank and pipework expertly cleaned before refilling the tank to prevent it from contaminating the clean fuel.
  • Arrange for a tank service to check the contamination has caused no damage or leaks to the tank itself or its components.
  • Don’t let fuel sit stagnant. If your tank isn’t regularly used, install a fuel recirculation unit to prevent the bacteria from settling and the sludge from forming.

For more information on the impact of water contamination, view our video.

Tags: fuel storage

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