– Fuel contamination can be felt in many ways, particularly in the mechanical operability of your engine or equipment. Some of these symptoms often go unnoticed, or ignored, while other symptoms can be severe and impossible to ignore.

Not only can these failures be extremely costly to repair, but these catastrophic failures can be dangerous, especially when they occur on the road or at high speeds.

Fortunately, many of these failures can be prevented through frequent fuel testing and the implementation of preventative solutions.

In this article we will cover the symptoms, causes, testing, and solutions for all types of diesel fuel contamination.


Posted September 9, 2019 by Tyler Moore

Fuel Contamination Article Cover Photo Showing Broken Down Semi Truck

Fuel contamination can be felt in many ways, particularly in the mechanical operability of your engine or equipment. Some of these symptoms often go unnoticed, or ignored, while other symptoms can be severe and impossible to ignore.

Not only can these failures be extremely costly to repair, but these catastrophic failures can be dangerous, especially when they occur on the road or at high speeds.

Fortunately, many of these failures can be prevented through frequent fuel testing and the implementation of preventative solutions.

In this article we will cover the symptoms, causes, testing, and solutions for all types of diesel fuel contamination.


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Part 1

Symptoms of Fuel Contamination

Causes of fuel contamination icon

Part 2

What Causes Fuel Contamination?

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Part 3

How To Test for Fuel Contamination

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Part 4

Solutions to Fuel Contamination


Symptoms of Fuel Contamination

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Don’t Ignore Your Check Engine Light

Many people have been or have known someone that was in a situation where the “check engine” light comes on in their vehicle out of seemingly nowhere. Anxious at first, they tone down their driving to see if they can feel any difference in how the vehicle is running.

Strangely enough, it doesn’t feel any different than before- so they convince themselves it probably isn’t anything other than the car or truck being a bit “finicky”.

At first a few days go by, then a few months. The light is still on and since the vehicle doesn’t feel to be running any different, it’s being ran just as often and hard as it normally would.

Under the hood however, components are not operating as designed, and the continuous operation of worn parts are damaging the very systems that keep the vehicle running.

At this point, detrimental engine failure could be just a matter of time, turning a repair of a couple hundred dollars into one that could quickly incur costs deep into the thousands.

Clogged Fuel Filters

Frequently clogged fuel filters are oftentimes one of the first initial signs of possible diesel fuel contamination. The filter is designed to capture particles in your fuel before they pass into the engine, and these pieces of matter can be made up of clumps of fuel sludge, metallic particles, or other unwanted particulate.

If a fuel system is experiencing an atypical recurrence of fuel filter replacements, the problem’s root could lie in the quality of the fuel being supplied to the filter.

Heavily contaminated fuel would consistently provide particulates and other undesired material that would quickly clog up the filters and possibly be leading to other issues in the fuel system.

This contamination could be stemming from either the fuel source itself, or from the internal corrosion of the very fuel tank being used to fuel the engine.

Failing Fuel Pump

With frequent fuel filter clogging, fuel pump failure is often to follow. Because of the restriction caused by the clogged filters, the fuel pump could be working harder than designed to deliver fuel from the tank to the engine.

While a fuel pump is failing, the fuel pump will not be able to deliver a steady flow of fuel, interrupting the mechanical stroke and function of the engine. This can be especially noticeable under acceleration, where fuel demand is increased however the fuel pump is unable to deliver the fuel at the requested rate.

Symptoms of a failing fuel pump may include:

  • Jerks or sputters at high speeds
  • Power loss on acceleration
  • Power loss while driving up a slope
  • Power loss while towing
  • Engine surging while acceleration is not engaged
  • Engine will not fire

When a fuel pump is exerted to the point of failure, it is past the point of simple maintenance to get the engine running again. When a fuel pump fails, fuel line pressure is lost thus not being able to deliver any fuel for the engine to fire up. Downtime of equipment for major repair is expected at this point to get the fuel flowing properly again.

Partial Injector Failure

Unfortunately, partial functional failure of an engine will often go unnoticed until it is too late.

Engine inefficiencies are seldom felt by a user but can result in serious losses in operability and revenue.

A major reason for engine inefficiency stems from partial failure of an engine’s fuel injection system, which isn’t well understood by a majority of people.

Injector partial functional failure isn’t a failure point that is well-documented in many industries, leaving a lapse in understanding of the symptoms that come with this kind of failure.

Although the equipment is still operable, partial functional failure of a fuel injection system is generally one that reduces engine efficiency or performance. The symptoms of such failures within an injection system may include the following:

  • Low power from the engine
  • Reduced engine RPM
  • Increased fuel consumption
  • Poor cycle times or low speed
  • Smoke
  • Lower gear selection
  • Noise
  • Poor starting
  • Poor idle

Many of the symptoms mentioned here are difficult to diagnose without the proper tools and equipment, which makes needed repairs something that often falls behind.

By continuous operation of the equipment, the user is at risk of experiencing events of catastrophic engine or component failure.

To understand the role fuel injection plays in the engine mechanically, one must understand the stroke cycle as referenced below.

Image showing the combustion stroke cycle of a diesel engine from induction, to compression, to power, to exhaust.

During the power stroke, fuel is injected into the cylinder and ignites, creating the energy needed to transfer to the mechanical output that drives the vehicle or equipment.

A diesel fuel injector, be it an electronically controlled unit or high-pressure common rail, reduces in its designed functionality the moment any of the designed tolerances within the injector alter, thus affecting the design of the fuel spray profile within the combustion chamber.

The changes in these injector tolerances can occur through the erosive and abrasive effect that contamination plays on metal surfaces, the alteration in injector nozzle hole size, or the number of open holes.

Any number of these factors can alter the engineered functionality of a fuel injector, leading to a snowball effect of internal engine damage that could eventually progress into full functional engine failure.

Catastrophic Engine Injector Failure

Catastrophic full functional failures are those that simply cause the engine to cease functioning. They are often dramatic events, highly visible to operations and high in cost and resulting equipment downtime.

It is for these reasons businesses that rely on the operability of equipment and the margins of revenue they produce focus their attention on monitoring, predicting, managing, and reducing such events.

Additionally, hourly-based planned maintenance strategies are specifically designed around preventing such failures through known Mean Time Between Failures (MTBF), advised by both OEM and industry specialists alike.

An excellent example of this are the mandatory fuel injector replacements at half engine life (based on operating hours) that many OEM’s advise as part of their warranty or maintenance program.

An obvious question should be raised here. If an engine is provided fuel at the OEM-specified fuel cleanliness level, then why would the fuel injectors need to be replaced halfway through the life of the engine?

Clearly, OEM’s are aware that cleanliness levels such as ISO 18/16/13 do not provide the fuel injection system with a cleanliness level that will ensure its ultimate reliability, and it is for this reason why fuel injector change-outs are recommended at engine half-life.

There are many types of common engine failures and most are typically well-understood and managed by engineering and maintenance/operations practitioners. However, there are some engine failures which can never be properly diagnosed or predicted, making it difficult for professionals to develop a suitable solution to the problem.

Some of these more common engine failures can be misdiagnosed, and if correctly analyzed, attributed to failures within the fuel injection system.

High velocity and high-pressure fuel flow, with even the smallest amount of contamination, will gradually erode the sealing surfaces of the injector valve seat.

Once valve wear has initiated, a chain reaction gradually occurs, resulting in a partial functional failure evolving into the full functional failure of the valve and the need for replacement.

The Failure Chain Reaction

  1. Valve erosion initiates
  2. Fuel leakage through the valve mating surfaces initiates
  3. Localized hot spot generation through the leakage zone causes fuel oxidation
  4. Reduced fuel pressure at nozzle
  5. Reduced volume of fuel delivered. Engine management system compensates by increasing injection event time (more fuel).
  6. Reduced fuel atomization
  7. Soot generation within the cylinder
  8. Increased emissions
  9. Loss of power
  10. Partial functional failure point
  11. Leakage rates continue to increase as wear continues
  12. Fuel consumption increases as the engine controller unit tries to compensate for leakage
  13. Visible and audible signs
  14. Full functional failure point

There are three principal locations inside a high-pressure common rail fuel injector that suffer from the erosive and abrasive effects of contamination, resulting in a loss of functional efficiency. These are:

  • Fuel injector nozzle holes
  • Needle valve and seat
  • Electronic Piezo or solenoid-controlled valve

Fuel Injector Nozzle

There are two predominant diesel fuel injector nozzle designs that are in circulation today: the area around pintel tip (SAC) and valve covered orifice (VCO) type nozzles.

Modern HPCR fuel injectors typically utilize the VCO type as it completely covers the nozzle holes.

This design enables the injector to abruptly and completely shut off the fuel at the end of an injection event, thus providing a more stringent control of the fuel injection event. The two designs can be seen below.

Graphic showing the differences between SAC and VCO fuel injector nozzle types.

Due to its design, the VCO type needle valve has extremely fine tolerances and is highly susceptible to valve misalignment during rise and fall.

Remembering that the rise and fall can occur 29 times per second at 1400RPM in a large heavy-duty diesel engine, any misalignment, or changes in the tolerances within the valve, will give rise to variations in the flow area, the volumetric fuel passing through the various holes, and the atomization of the fuel – all of which effect the combustion of the fuel and fuel efficiency.

Fuel injector nozzle holes generally have two failure conditions which result in a partial functional failure of a fuel injector. These two conditions are Blockage and Erosion.

Graphic showing how a high pressure common rail fuel injection system works.

HPCR fuel injectors are finely tuned and balanced precision devices that are designed to inject a very fine fuel mist consisting of micro-fine droplets into the combustion chamber with millisecond precision timing. Fuel droplets burn from the outside in, and as such, it is important for the fuel injection system to maintain the consistency of the mist for correct and efficient combustion to take place.

Modern HPCR fuel injection systems are specifically designed to reduce the droplet sizes of the fuel while increasing the number of injection events per engine cycle. When correct combustion takes place as designed by the injector manufacturer, the fuel droplets burn out completely before they reach the engine cylinder liner.

Failure to complete combustion in this way results in the build-up of soot within the engine and increases in nitrogen oxide (NOx), carbon monoxide (CO), and diesel particulate matter (DPM).

To maximize combustion efficiency and reduce emissions, modern HPCR fuel injectors typically have 5-8 very fine holes which are machined into the injector tip using a process called Electro Discharge Machining (EDM).

These holes allow the fuel to exit the fuel injector and immediately atomize within the combustion chamber. The size of these holes will vary from manufacturer to manufacturer and depends on the size and application for each fuel injector. Hole sizes are typically 20μm-250μm.

As a fuel injection event takes place, diesel fuel is sprayed into the combustion chamber, which unlike gasoline engines, is typically housed inside the piston crown.

As the piston moves downwards in its power stroke, sprays from the injector protrude further into the volume of the combustion chamber. Fuel should be burnt out before any droplet reaches the cylinder walls.

When, however, the spray pattern generated by the injector is not as designed, the fuel droplets become larger and therefore take longer to burn out. Soot generation, high diesel particulate matter (DPM), and smoke are by-products of this problem.

The soot generated within the combustion chamber gradually builds up on the injector tips, causing blockages to occur, as well as, accumulate within the exhaust system, the valves, and on cylinder walls where it is typically removed by the piston moving up and down and thus washed into the engine sump where it contaminates the engine oil.

Excessive soot buildup within engine lubrication oil is directly correlated to poor fuel injection or combustion.

Fuel injectors that have one or more of the nozzle holes blocked due to contamination or soot build up will cause an increased fuel velocity through the open nozzle holes, thus reducing atomization.

Micron sized contaminants can also gradually block some or all of the individual nozzle holes as a result of tight injector clearances and the electromagnetic conditions present inside. Nozzle holes that remain unblocked will see an increased flow rate, causing fuel to be ejected faster and increase the potential for wear.

The jetting of fuel (a continuous stream of fuel in a concentrated direction) within the cylinder can eventually result in the engine lubricating oil to be washed from the side of a piston and cylinder if left unchecked.

This loss in lubrication film can result in the development of a hot spot and uneven thermal expansion of the piston, potentially causing the eventual piston seizure to the cylinder sleeve, resulting in a catastrophic failure.

Interestingly, such failures are commonly categorized as lubrication failures and not the result of poor fuel injection.

The common approach to rectify the buildup of soot or contamination within the injector is to seek out and use diesel fuel additives that are designed to clean soot from the injector tip and internal deposits.

While this can be an effective means of cleaning the injector, in most cases the problem continues, as the root cause of the problem (contaminated fuel and worn injectors) has not been corrected.

Again, it must be stressed that the buildup of contamination and soot is a symptom of a far greater problem that should be corrected as a first step.

Graphic showing the injector needle valve in relation to the injector nozzles.

Fuel Injector Needle Valve

Contaminants in diesel fuel also have an erosive effect on the needle valve within the injector. This valve is designed to seal off the fuel within the injector following an injection event.

Poor sealing of the valve can result in the fuel injector dripping fuel into the cylinder and onto the piston crown. This problem is more predominant within HPCR fuel systems with the fuel injector being pressurized 100% of the time.

Such problems were less evident with EUI systems where full fuel injection pressure only exists for 5% of the engine run time. Dripping fuel injectors can cause a multitude of problems and catastrophic failures.

The predominant failures caused by dripping fuel injectors are excessive piston crown temperatures causing the crown to deform or melt, resulting in engine failure.

Fuel Injector Control Valve

All electronic controlled fuel injectors, either EUI or HPCR, incorporate a control valve that is used to control the timing of each fuel injection event. In EUI type fuel injectors, the valve is controlled via an electronic solenoid.

Most new HPCR injectors are controlled via a Piezoelectric actuated valve, which enables far greater control of valve movement (distance) and a far greater control of speed. No matter how the valve is actuated, it is by far the most critical component and the most sensitive to contamination.

In most applications where HPCR fuel injectors are employed, the control valve inside the injector only opens a distance of approximately 20-30μm. When open, high-pressure fuel up to 40,000 psi travels over the metal sealing surfaces at speeds faster than a jet airplane.

Extremely fine contaminants suspended within the fuel gradually erode and damage the sealing surfaces and the fine-machined tolerances.

Additional problems occur within the control valves when ultra-fine contaminants below 4μm, enter the critical clearances between the valve pintle and the valve body. The trapped silt within the clearance zone restricts the movement of the pintle, which results in sluggish movement of the valve, poor injection timing and eventual seizure.

Such seizures typically result in the solenoid coil or the Piezo failing or a fault signal within the ECM. These failures are almost always classified as electrical faults by either manual detection or the ECM, when in fact it is contamination that has initiated the problem.

High velocity and high-pressure fuel flow, with even the smallest amount of contamination, will gradually erode the sealing surfaces of the injector valve seat.

Once valve wear has initiated, a chain reaction gradually occurs, resulting in a partial functional failure evolving into the full functional failure of the valve and the need for replacement.


Causes of Fuel Contamination

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Particulates in the Fuel

Undesired particulate within diesel fuel is one of the most common contaminants. From microscopic fragments of ferrous metals to dirt and grime that is introduced to the fuel, various contaminants can be to blame for a majority of fuel-related issues.

Following the refinement process, fuel most likely passes through numerous tankers, trucks, vessels, and storage before it reaches you. Because of this, there are many potential sources of unwanted particulate contamination. Older fuel tanks, particularly those made of black iron, are highly susceptible to rust and corrosion.

Because of corrosion, fuel that was previously clean could be contaminated when introduced to a tank that has rust build-up within. If in a transport tanker or truck, constant vibrations and sloshing could mix the particulates with the fuel to a point where all of the fuel is contaminated.

This fuel can often find its way into other tanks for distribution and bulk storage, where it can then contaminate other tanks or equipment, as well as other fuel that will eventually find its way there.

This cycle evolves into a constant problem for equipment and engine operators, making it difficult to pin-point the source or cause of contaminated diesel fuels.

Rarely is it known exactly where fuel has been passed through before making it to you, leaving the likelihood of receiving contaminated fuel to chance.

Water Contamination

Water in diesel fuel is one of the most troubling types of contaminants, and also one of the toughest to combat in large bulk fuel tanks.

Since fuel is often kept, transferred, and purchased out-of-sight, contamination and build-up of water in diesel fuel can be extremely difficult to spot, unless it is properly tested for.

Not only this, but engine damage from water contamination in fuel can be very costly.

Water can enter the fuel in a number of different ways.

Diesel fuel is a hygroscopic fluid, meaning that it is able to absorb moisture from the air around it. This can become a problem in fuel tanks where full capacity is not maintained for extended periods of time.

By allowing the fuel in a storage tank to have more air overhead to pull water from, emulsified water can develop and become mixed with the fuel in suspension.

Combined with water from condensation, this results in an unfavorable ratio of fuel to water, which can result in contaminated fuel being introduced into the engine or equipment it is being supplied to.

In some cases, water contamination can cause fuel injector tips to explode, should the water make it through the fuel filter and into the engine.

As a potentially catastrophic contaminant, excessive levels of water in fuel can reduce engine performance because of the reduction of energy available within the fuel.

Not only this, but water in fuel can increase the temperature the fuel will freeze within engine components. This can be especially problematic in cold climates where fuel gelling is already a concern.

Another type of water contaminant is free water. Free water develops as a layer beneath stored fuel after phase separation occurs.

With the presence of free water in a fuel storage tank comes the possible proliferation of microbial growth within the fuel.

When the presence of free water is ignored, the microbial growth will live and grow in the layer where the water meets the fuel. Hydrocarbons in fuel provide food and energy for the “diesel bug”( that is often referred to as “algae”) to rapidly spread.

Once microbial growth exists in a fuel tank, sludge develops as a waste byproduct of the hydrocarbons being consumed by the microbes.

Water in diesel fuel can lead to bigger issues.

To learn more about the diesel bug and possible solutions: check out our article on ADDRESSING ALGAE IN DIESEL FUEL.

Fuel Degradation

Fuel indeed “goes bad” over extended periods of time in storage.

Many people aren’t aware that diesel fuel has a shelf life, however fuel stability is important to mechanical operability of your engine.

Good fuel samples are typically bright in color and clear. Degrading fuel samples can often be determined visually, with fuel turning dark and murky because of the development of tar and asphaltenes within the fuel.

High sulfur diesel shelf life recommendations are less than a year, while ULSD and biodiesel blends have an even further reduced long-term stability.

When fuel loses stability during degradation, the gums and waxes that develop can contribute to corrosion and damaging deposits on engine components.

Many automotive mechanics will first flush fuel lines and replace the fuel if a troubled vehicle was known to be sitting for even a few months.

With most engines designed to be in frequent use, such as fleet vehicles, fuel stability isn’t something most consumers have at the top of mind.

If you have fuel that is going to be sitting for extended periods of time, such as bulk fuel storage for a fleet or on-site fuel storage for backup generators, equipment managers should be aware of fuel stability timelines.

Diesel fuel composition can begin to change within a month of sitting in storage, with recommended maximum storage timelines without significant degradation of six months to one year.

However, these recommendations are contingent on the fuel being purchased from suppliers and stored in tanks with the appropriate cleanliness and quality standards.

To properly store fuel (especially in large amounts) for extended periods of time, fuel should be polished to maintained optimum fuel quality that is ready for use at any moment.


How to Test for Fuel Contamination

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Fuel Testing Tools

To be proactive and catch fuel contamination early, fuel should be sampled and tested from a bulk fuel storage tank at least once every six months. Testing for different contaminants can be achieved in a number of ways, here are the most common tool for fuel sampling and testing:

Proper Fuel Sampling & Testing

Fluid sampling pumps are often used to obtain fluid samples from hard-to-reach spots using flexible tubing. This allows for fluids to be drawn without the worry of cross contamination, as the fluid never comes into contact with the pump.

Fuel tank samplers, also known as “bacon bombs”, are industrial-strength stainless steel devices used to remove liquid samples from a bulk fuel storage tank. The device is lowered into a fuel tank until the sampler’s plunger makes contact with the bottom of the tank.

The plunger then opens, which admits a sample into the unit. To sample from any desired level in the tank, the plunger can be actuated by a pull-chain attached to the device.

Once fluid samples are obtained, they must be sent to a lab for testing. Getting results from the lab could take days, up to waiting periods of weeks.

For quicker results, Kolor Kut ® Water Finding Paste is a product used to instantly report if there is a presence of water in petroleum fluids such as gasoline, kerosene, diesel, and heavy fuel oil. The paste is applied to a rod and dipped into the tank, with the color of the paste changing instantly upon contact with water.

FUELSTAT ® PLUS is a simple fuel testing kit that provides results in less than 10 minutes. The objective of the test is to provide rapid screening of fuel samples to give a quick and accurate assessment of H. Res., bacteria & other fungi within the fuel.

Liqui-Cult Microbial Test Kits accurately detects and quantifies bacterial and fungal growth in a variety of fluids. Liqui-Cult tests for microbial growth in fuel samples over a period of a few days.

Through frequent fuel testing, the presence of contamination can be determined and action plans can begin to be determined. Depending on the scope of contamination levels and volume of fuel contaminated, some solutions may be more practical to implement than others.


Solutions to Fuel Contamination

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What is Fuel Polishing?

Fuel polishing is a fuel filtration technique used across many industries to increase and maintain fuel quality in stored fuel. Through these fuel filtration systems, various forms of contamination are removed and prevented.

Mobile Fuel Polishing

These polishing systems can be mobile units built onto carts or skids, or these systems can be mounted (sometimes in an enclosure) that is plumbed into the bulk fuel storage tank.

Mobile fuel polishing system removing sludge in fuel.

The mobile polishing systems are advantageous when having to maintain a number of different fuel tanks without having to incur the financial cost of installing multiple fixed systems. Mobile systems come in a number of different sizes and flow rates, and we recommend you visit our Mobile Fuel Polishing page to view the different systems that are available.

Mobile fuel polishing may seem like the perfect solution especially if you have multiple tanks, however that is not always the case.

As these units are not fixed onto the fuel storage tank, these systems must be hauled out on a scheduled basis to maintain fuel cleanliness. The problem arises not when fuel is cleaned to the desired fuel cleanliness standard, but rather when fuel is again left to sit untreated.

This causes the fuel to fall back out of the desired cleanliness specifications where it must be polished again. This creates a cycle, which is illustrated below, that gives chance that the fuel fails to maintain the quality requirements if stringent polishing cycles are not maintained.

Now, you can see where this fuel polishing cycle could turn into something that proves to be quite taxing, especially in situations where multiple fuel tanks on a specific site need to be treated on a regular basis.

Automated Fuel Polishing

Automated fuel polishing systems can be beneficial to fuel storage in facilities where frequent access for mobile polishing isn’t preferred or practical.

Our Automated Fuel Maintenance and Enclosed Fuel Maintenance systems are engineered to allow for the scheduling of periodic fuel polishing so that fuel is constantly being cycled and polished. This eliminates the concern for fuel to fall out of the desired fuel cleanliness and quality standard.

Fuel maintenance systems are the best way to remove algae from diesel fuel.

For facilities that are reliant on backup power systems, this is immensely important. Mission critical facilities, such as hospitals and data centers, cannot risk electrical downtime in the event of a power outage.

With these facilities having large volumes of stored fuel to power the backup generators, it is important that fuel quality is maintained to ensure quality fuel is delivered to the backup power system at a moment’s notice. Any fuel quality issues could render the backup generator inoperable, putting critical systems at risk.

Levels of Fuel Filtration

Fuel polishing systems have a number of components necessary to ensure that fuel is being cleaned and contamination is removed in an appropriate manner.

Micron filtration removes clumps of fuel and other particulate that could harm equipment. By passing fuel through micron filters, contaminants such as dirt, grime, and sludge can be caught by the filter and removed from the fuel.

With water separation, free water is captured and removed from the fuel to prevent the proliferation of microbial growth. By capturing the water, fuel polishing systems effectively remove the conditions to which “the diesel bug” thrive.

Not only that, but by removing the water from the fuel it keeps the engine and fuel injection system from receiving water that could pose harm to the integrity of the equipment.

AXI International’s LG-X Inline Magnetic Fuel Conditioners are a proprietary part of our fuel polishing systems that use a magnetic field to achieve a number of things.

Through running fuel through the magnetic chamber, metallic particles and fragments are captured and thus prevented from making its way into critical engine components. These metals could be comprised of various ferrous metals or even rust.

Rust is typically a sign of the presence of water within a fuel tank. Rust can only develop where there is water, and if fuel was previously clean but rust was found during the polishing cycle of a fuel tank- chances are that there is water present as well.

The magnetic field is also responsible for breaking down clumps of diesel fuel known as agglomeration where the ions in diesel fuel, over time, naturally pull together creating thick clumps of fuel. By passing these clumps through a magnetic field, the bond is broken and returns the fuel clusters to a fluid state.

Fuel Additives

Fuel additives can also prove to be beneficial for those concerned with fuel contamination issues. However, with such a wide variety available on the market, it could be hard to decide which additive is best suited for your unique needs.

Fuel stabilizers as a fuel additive work in a manner that prolongs the stability of fuel in storage. These fuel stabilizers are often used in circumstances where fuel is expected to sit for an extended period of time without any fuel maintenance.

By dosing the fuel tank appropriately, this fuel additive prevents fuel from oxidizing and experiencing a chemical breakdown.

Combustion catalysts can be used to not only enhance engine performance, but also provide for a more complete burn of fuel being supplied to the combusting cylinder, which results in reduced carbon deposits. This, in turn, reduces engine emissions as less unburnt fuel is released from the exhaust system.

By increasing power output, combustion catalysts can often result in a healthier engine response.

Corrosion inhibitors in certain fuel additives prevent corrosion on metal surfaces, which prolong engine life and equipment operability. This reduces the amount of “surprise” equipment maintenance that is needed due to the failure of certain parts within an engine’s mechanical system.

The corrosion inhibitor is comprised of compounds that attach to component surfaces and form a film that acts as a lubricant which reduces engine wear and extends the lifetime of mechanical components.

We recommend AFC Fuel Additives as the go-to fuel additive to add to your fuel maintenance schedule. As the only fuel additive offering all of these features and benefits within a single formula, AFC Fuel Additive is the smart choice for your equipment. With a concentrated formula, just eight ounces of AFC Fuel Additive is able to treat 320 gallons of fuel. AFC is also available in 1 Gallon (treats 5,000 gallons), 5 Gallon (treats 25,000 gallons), and 55 Gallon (treats 275,000 gallons) quantities.


Through gaining an understanding of what diesel fuel contamination is, what causes it, how to test for it, and how to treat and prevent it, we hope to give you greater in-depth knowledge on just how critical your fuel quality is.

From lawnmowers to tractor trailers, fuel quality is something that affects everyone logistically- for it could be the reasons behind your car not running and your generator failing. Sometimes, the application is small, and fuel is simply replaced before damage is done and you are on your way again.

But, in many cases, this can be a costly solution especially when there are thousands of gallons of fuel at risk. And in the worst-case scenario, this fuel can not only be contaminated, but also further contaminate and cause detrimental mechanical issues within the equipment the fuel was being supplied to.

Engines and equipment rely on quality fuel to operate as designed, and when that standard of fuel isn’t being supplied (which is often the case), gradual wear and breakdown of components could lead to costly repairs, particularly in and around the fuel injection system.

To ensure fuel quality and mitigate the effects of contamination, it is recommended to instill fuel maintenance systems and procedures. At the general consumer level, this could mean using a fuel additive when you fuel up your vehicle. At the business operational level, this could mean installing automated fuel management systems to polish bulk fuel and prevent contamination from proliferating.