Identifying and preventing diesel contamination in your heavy duty machinery
Diesel contamination is an issue that has become more prevalent in the past couple of decades, with more stringent fuel emission regulations increasing the importance of using cleaner diesel in heavy machinery. In the past, fuel had a longer storage life and contamination was less of an issue, however diesel nowadays is made from a mixture of 93% petrochemical diesel and 7% biodiesel, making it more environmentally friendly, but also more prone to contamination.
What causes diesel fuel contamination?
The fatty acid methyl ester (FAME) present in biodiesel makes it more eco-friendly, but also lends itself to conditions favourable to organic contamination. Water contamination and solid particulate ingress are also leading causes of fuel contamination in heavy machinery.
What are the types of diesel contamination?
There are 3 main types of diesel contamination: water, microbial (aka ‘diesel bug’) and solid particulate.
Water contamination
Water can be present in diesel as either free, dissolved or emulsified. Often, water can enter through storage tank vents and humidity and temperature changes can exacerbate the issue. When air containing high levels of moisture enters the tank, the water from this air eventually condenses, resulting in water contamination.
Another cause of water contamination in diesel is internal temperature changes within the engine components . Hot diesel returns to the tank after being used to cool fuel injectors and ECMs, and the temperature difference between this diesel and the rest of the diesel in the storage tank causes condensation.
Water contamination can accelerate the oxidation of fuel, corrode the tank, and even encourage the growth of microbes in diesel fuel.
Microbial growth contamination, aka ‘Diesel Bug’
Microbial growth within your heavy machinery’s diesel includes bacteria, mould and fungus growth. Water inevitably collects at the bottom of your diesel tank over time, and this provides the ideal environment for microbes to grow. As microbes spread, a slime is produced which floats on the fuel and a thick sludge will often build up in the bottom of tanks.
The issue with ‘diesel bug’ is that the acids released by the process of microbial spread can both accelerate the breakdown of your machinery’s diesel and corrode the tank. Microbiologically-induced corrosion (MIC) speeds up the deterioration of your engine’s metal parts, including the diesel tank itself.
Solid particulate contamination
The third and possibly easiest way in which diesel can be contaminated is by solid particles or foreign body ingress. This includes dust, engine rust, wear particles and any small, abrasive particles which should not be present within your diesel fuel.
These particulates tend to make their way into your diesel during fuel transit or through a tank vent.
The presence of engine rust and wear particles can be exacerbated by other contaminants we’ve mentioned previously, like MIC of your tank, as well as by poor maintenance of your heavy machinery’s engine parts.
What are the signs of diesel contamination in heavy machinery?
There are many signs that could indicate diesel contamination in your heavy machinery, including:
- A rise in fuel consumption as contaminated fuel becomes less efficient.
- Lower engine output and more revs, which is suggestive of poor quality fuel through contamination.
- A rotten smell caused by sulphur released by microbes.
- Pits and wearing in piston rings and cylinders due to acidic erosion of solid particulate abrasion.
- Excess smoke, signalling incomplete combustion because of diesel contaminants (your heavy machinery should not be producing dark or white smoke).
- You find yourself replacing fuel filters more often than usual, caused by partical ingress microbial sludge blocking the filters.
- The appearance of sludge or slime in your diesel.
How to avoid diesel fuel contamination for your heavy equipment?
There are a few key ways to avoid diesel contamination in your heavy machinery, and as always, prevention is key.
Fuel tests are available as a preventative measure and these are ideal for sites storing large amounts of diesel. These tests can accurately measure the amount of water present in your diesel and can identify microbes too.
Water contamination can be avoided or lessened by using a concentrated fuel treatment on your diesel, and water can also be manually pumped out of your storage tank if levels are high enough.
To reduce sludge build up, fuel stabilisers can help. A diesel anti-microbial can also prevent the formation of sludge in the first instance too. The key point to remember with microbial sludge or diesel bug is that it needs to be managed as early on as possible before microbes have a chance to multiply and spread through your heavy machinery’s parts, which can be a much more difficult issue to solve.
By checking your tanks for water and sludge build up every couple of months, you can keep on top of the quality of your heavy machinery’s diesel and avoid more extensive contaminant build up down the line.
At Jaytrac, we supply high quality replacement parts for your Caterpillar , Cummins, Perkins engines, including fleetguard filters and fuel injection parts. To find out more, get in touch with us today by calling us on 01604 491 133 or emailing us at sales@jaytrac.co.uk. Alternatively, use our online enquiry form to send us the exact details of what you need and a member of our friendly team will get back to you.