Can Diesel Fuel Go Bad?

Let’s address two common questions – does diesel fuel go bad, and what exactly does it mean for this type of fuel to ‘go bad’ in the first place?

Back in the 1950s and 60s, diesel fuel could last for years when it was stored. But now, unless the fuel is treated, you probably won’t get anything more than a year out of it.

When Fuel Goes Bad

When diesel fuel is exposed to an outside element that accelerates its natural degradation process, it goes bad.

Every type of petroleum fuel, whether it’s petrol or diesel, is made of an array of molecules of different sizes and lengths and starts out with unstable molecules. These unstable molecules are called ‘precursors.’ As time goes on, the precursors react with other molecules and start chain reactions that force the fuel to form gums, varnish, and sludge, turning it dark and stratified. Fuel in this condition counts as fuel that has ‘gone bad.’

Bad fuel is fuel that no longer does its job. Darkened fuel or fuel full of sludge or varnish won’t burn properly and creates black smoke. It might not even start an engine at all.

This process of ‘going bad’ is something that fuel has always done – but today, the process is faster than it’s ever been. The life of usable diesel fuel is now measured in months instead of years.

Environmental Factors

The three environmental factors that accelerate the process of fuel going bad are:

  1. Air
  2. Water
  3. Heat + light

Heat and light make fuel go bad at a faster pace because these two things provide the energy that drives the chemical reactions that break fuel down.

Another major factor in fuel going bad in present years is microbial growth. Because modern diesel fuel doesn’t contain as much sulphur as it did in years past, there are no elements that prevent microbes from growing.

Microbes have the power to make diesel fuel go bad at a quick rate because they multiply inside the fuel and create biomass formations, and these formations produce acids that attack the diesel fuel and break it down.

The Life of Diesel Fuel

Diesel fuel does go bad – but how fast it goes bad depends on how you store it. To learn how to store your diesel fuel in optimal conditions, get in touch with us at ServoPro.

 

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