Diesel Fuel Quality is a Question Not a Guarantee

Deterioration of diesel quality and its effect on engines


When it comes to the "acceleration" of diesel fuel quality, it just doesn't compare to the diesel engines it's supposed to "rev" up.

Diesel engine designs striving to increase engine performance have made great advancements in engine fuel delivery to the combustion chamber. Today's diesel engine is quieter, smoother and more powerful. But today's diesel engine owners are overlooking one important factor. The quality of today's diesel fuel has not advanced at the same rate as the engine improvements.

Diesel fuel begins to deteriorate as soon as it is produced. Within 30 days of refining, all diesel fuel regardless of brand, goes through a natural process called re-polymerization and oxidation. This process forms varnishes and insoluble gums in the fuel by causing the molecules of the fuel to lengthen and bond together. These components now drop to the bottom of the fuel tank and form asphaltene also known as diesel sludge. The fuel begins to turn dark in color, smell bad and in most cases causes engines to smoke. The engines smoke because some of these clusters in the early stages are small enough in size to pass through the engine filtration and into the combustion chamber. As these clusters increase in size, only part of the molecule gets burned. The rest goes out the exhaust as unburned fuel and smoke. With increases in cluster size they begin to reduce the flow of fuel by clogging filters. The filters only address the symptom and not the cause.

It is estimated that eight out of every ten diesel engine failures have been directly related to contaminated fuel. The build-up of contaminates in the fuel systems and storage tanks can quickly clog filters, thus resulting in engine shut down, fuel pump wear and diesel engine damage.

The Culprits

Understand that most fuel has some amount of water in it from either condensation or vents. This threat requires that we realize the added burden placed upon diesel fuel as opposed to gasoline. Gasoline acts as a fuel only. Diesel fuel, on the other hand, also must cool and lubricate injection system parts. These parts are engineered to very close tolerances -- up to 0.0002 of an inch -- and any contamination means rapid part wear. Water displaces the diesel fuel. When the fuel is displaced wear occurs because lubrication is now absent.

Water that enters the combustion chamber results in even more serious damage. When it comes in contact with the heat of the combustion chamber (in excess of 2,000 degrees F), it immediately turns to steam and often explodes the tip of the injector. Water causes corrosion of tanks, lines, injectors and greatly reduces combustibility.

Other areas of concern include the generation of more exhaust emissions and effecting EPA standards.

Bacteria also presents a serious problem. Bacteria feeds on nitrogen, sulfur and iron that may be present in the fuel or tank.

Then there is algae. There is absolutely no algae in diesel fuel. You may have fungus and microbial contamination but no algae. This is a misnomer for diesel sludge. So if you have a diagnosis of ALGAE and add a biocide, you have done two things, 1) found a mechanic that is wrong and 2) done nothing to fix the problem.

What your engine manufacturers recommends

Your engine manufacturers recommend that your fuel not be stored for more than one year and to operate on fuels meeting the properties of ASTM designation D975 (grades 1-D and 2-D).

If you have stored fuel or have fuel of questionable age and have to polish it by an outside service, you may be shocked at the going rate of "half the price of new" to clean your fuel. This number can really affect your maintenance budget. Fuel polishing is the repeated filtering of the entire tank volume on a regular basis. Turning the entire volume of the fuel every thirty days is recommended, but most only do it once in 120 days. Running equipment for an hour that depends on that fuel is a waste of time. The OEM filtration on an engine is not intended to process hundreds or thousands of stored gallons. A fuel management system is required with the specific capabilities to handle your volume of fuel.

This content continues onto the next page...

We Recommend