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Why Does Diesel Fuel Go Bad?

Stored diesel used to last for years – nowadays its shelf life is measured in months.

Diesel fuel eventually goes bad, that’s just a fact. Three things speed up the natural process of good fuel gone bad – water, air, and warmth. Those three things will always hasten your bright clean fuel’s downward spiral into murky sludge. You end up with a fuel that won’t cooperate, fuel that just won’t burn like you need it to.

But why does diesel go bad faster now than it used to in the good ol’ days?

Well, that’s because of sulfur. Or rather, the lack of sulfur. See, diesel used to have higher levels of sulfur in it – which microbes hated. The ultra-low sulfur diesel we have now? Well, it’s just a cozier environment for the bugs that want to settle in and raise a family. So that’s exactly what they’re doing.

Fuels are made up primarily of carbon chains of varying lengths. These molecules break

down over time, especially when exposed to the three ageless culprits of deteriorating fuel quality – water, air and warmth. Those microbes though? It’s not just that they CAN degrade your fuel, it’s actually their preferred food source. Adding insult to injury, their waste products actually hasten your fuel’s demise – their acidic byproducts further break down the chemicals in the fuel.

So let’s say you’ve got a tank of generator diesel, tucked away, out of sight, out of mind. Water creeps in, microbes set up camp, the fuel starts breaking down… before you know it, you’ve got a tank full of acidic sludge that isn’t good for anything.

You can’t just leave diesel unattended. It’s like a quiet toddler – it’s up to something. For a quick assessment, check the color of the fuel – look for discoloration or opacity. If it doesn’t look right, chances are it isn’t right. Is there water in the tank? That’s just asking for trouble.

Generators are especially important – they exist as a back-up plan in case of emergencies, when they absolutely must run. This is why Clean Fuels National has maintenance schedules specifically tailored to generator fuel supplies. We maintain the generator fuel supply for countless hospitals – checking the quality of the diesel at regular intervals, so you’ve never surprised by what’s in your tank. As soon as a problem is detected, we correct it.

Sometimes, it’s as simple as removing water – other times, it may require the use of biocides, followed by aggressive cleaning and filtration. We are very familiar with the needs of our customers that require regularly scheduled inspection – from schools to hospitals.

Don’t let quiet contamination destroy your fuel – let us help you keep an eye on your supply! A representative is always available, so don’t hesitate to call!


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