Road diesel & gasoil now contain a percentage of bio-fuel (up to 7%). This provides an ideal breeding ground for diesel/gasoil bugs (Check out our article explaining diesel bug in more detail).

Equipment failure can be down to bugs in these modern fuels. Problems with contaminated fuel inside storage tanks can cause pumps & vehicle filters to block, & in severe cases, vehicles can stop working causing downtime & hefty repair bills.


These issues are caused by microbial contamination (often known as diesel bugs which are micro-organisms that grow on water present in fuel). This problem has been known but contained for years until the age of the latest fuels.


How Do Diesel Bugs Form? 

The tank becomes an incubator as the variation of temperature, condensation & the added percentage of bio-fuel (which attracts water as it is hygroscopic) helps these bugs to flourish.


Over a period of time living microbes grow into large colony forming units (CFUs) which get sucked into fuel supply lines, blocking filters on dispensing pumps & vehicles. Microbial contamination is most commonly seen as sludge that forms in the bottom of storage tanks & accumulates on filters.


This sludge also contributes to poor emissions (seen as black exhaust smoke).


In addition to this even fuel with a small percentage of bio-fuel will act as a detergent - cleaning the inside of the storage tank, pipework & valves, allowing the dirt & sludge to be sucked up by pumps, blocking filters.


Bio-fuels can contain up to 25 times more water than mineral diesel, increasing the risk of serious & expensive damage to fuel injection systems.


So What Can Be Done? 

Tank hygiene is important & is an ongoing requirement.


Simple housekeeping is the best way to prevent contamination.


A few simple tips include:

  • Regularly check for the presence of water.

  • Inspect your tank, checking for points of water ingress.

  • Bottom out your tank to remove any free water & sludge.

  • Have your fuel tested regularly for microbes.

  • Fit a fuel conditioner to your suction or vehicle fuel lines.

  • Fit water particle filter to your storage tank (fit to delivery side of pumps).

  • Use tank dryers in fuel stores & vehicle tanks when not in use.