Diesel contamination and cleaning

Call us today for a chat about your fuel problem 1300 838 111


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As you wouldn't eat bad food, you shouldn't feed your engine bad diesel! An engine that runs on clean diesel is more efficient, better for the environment and more reliable, preventing unexpected stops caused by clogged fuel filters. Clean Diesel Australia has developed the most comprehensive diesel cleaning process with 7 stages of filtration and fuel conditioning to ensure a thorough cleaning of your fuel. We offer installation of inspection hatches and cleaning ports, diesel tank cleaning and fuel polishing in Melbourne, Canberra, Sydney and Brisbane. 

 Get access to your tank for a full clean up with our innovative tank inspection hatches built to ISO standard 21487:2012. They are made in Australia from premium 316 stainless steel which won't corrode like aluminium or crack like plastic and come with a lifetime guarantee. Installation is provided by Clean Diesel or by one of our accredited installers or, if you have the right tools and the required skills you can do a DIY installation in less than an hour. For more details about CDIH (Clean Diesel Inspection Hatches), CDCP (Clean Diesel Cleaning Ports) and installation instructions please click the image below.

All series


Recommended every 12-24 months. Maintenance programs available upon request


If your tank has never been cleaned and you are experiencing problems with blocking filters then you probably need a comprehensive inside of the tank clean up as a regular fuel polishing or chemical additives may not work. 


Diesel fuel contamination


Of all contaminants, water is the worse. Water causes damage to fuel tanks, fuel system components and engine. One way or another, especially on boats sitting on the water, the water will find its way in your boat's tank either by refuelling with water contaminated fuel, condensation, leakage, ingress from atmosphere (humidity) and sometimes human error. Due to the nature of marine diesel tanks, the fuel is constantly agitated and that increases the emulsified water percentage (water that will not drop at the bottom to be drained or removed with water absorbent products). Emulsified water can be removed by using a de-emulsifier diesel agent that will allow the water to separate from fuel and drop to the bottom of the tank where it can be drained using conventional methods. Diesel contamination, its effects on engine performance and operation have been studied and researched countless times since the introduction of the first diesel engine in the 1890s by Rudolf Diesel.

The biocides and fuel additives will not work effectively if your tank is contaminated with sludge internally on the walls and bottom. The surface layer of dead cells (top of the sludge) acts as a protection for the microbial growth that takes place beneath. With constant agitation of the diesel tank of a boat, some of the sludge becomes dislocated and can block your filters causing the engine to stop.  

Diesel Bug was always a problem for diesel fuels, however, since the introduction of Ultra Low Sulfur Diesel (ULSD) it has become more and more evident, as sulfur was used to inhibit microbial growth in diesel fuels. The problem gets worse when biodiesel is added to ULSD and according to Australian Standard of fuel quality it can be up to 5%. The reason is that, compared to regular diesel, biodiesel is much more hygroscopic (attracts water). Studies found that biodiesel can absorb up to 25 more water than diesel and as the temperature increases above 35°biodiesel has an increased rate of 22.2ppm/°C - 9 times more than regular diesel. That is the reason why tanks situated in the engine room or in higher temperature areas have worse microbial contamination (up to few centimetres thick on the bottom of the tank). When that happens the primary fuel filters become constantly clogged.

While there is NO WAY to prevent water entering your fuel tank, we at Clean Diesel have many solutions to stop the damage and keep your marine engine in good condition.  

In the early 2000s, DOW Chemical Company, the second largest chemical company in the world, conducted a study about microbial contamination of diesel fuel, its impact, causes and prevention. It is the most comprehensive technical article that will explain in detail everything there is to know about diesel contamination. After analysing all aspects of diesel microbial contamination the study concludes:

"Despite growing evidence of the significant adverse economic impact of microbial contamination on diesel and gas turbine engine operations, only a few operators treat their fuel with biocides. One reason for this is the subtle nature of microbial contamination, which goes undetected until catastrophic failure takes place. Fuel performance, system integrity, filter life and engine life can be degraded significantly by the direct and indirect effects of microbial activity. Consequently, treatment with a fuel preservative can have a positive economic impact on bottom-line operational costs."

Read the full article HERE

To effectively remove the contamination from the diesel fuel we have developed our own equipment and technology that uses an innovative multi stage filtration process to ensure a thorough clean of the fuel, tank and fuel system. Our innovative cleaning process uses a scientifically proven cell disruption method that ensures 100% elimination of microbial contamination (diesel bug) from fuel, bottom and walls of the tank.



IMPORTANT: We recommend that after every diesel tank cleaning/diesel fuel polishing procedure you replace primary and secondary filters on your boat to ensure a 100% clean fuel system.

For more information or a quote call us on 1300 838 111 or fill in the CONTACT FORM.