Freightliner fire truck
Today’s advanced engine technologies can be more susceptible to premature failure and damage from contaminated or substandard fuel and antifreeze/coolants.
Photo credit: Photo courtesy of Daimler Trucks North America
The sample on the left is clean clear fuel. The sample on the right shows ashphaltene contamination (sludge).
Photo credit: Photo courtesy of Penray
A corroded temperature sending unit. Checking this part is important in preventive maintenance as it can reveal metal wear.
Photo credit: Photo courtesy of Penray
This photo shows failure of an engine front end cover caused by poor coolant maintenance.
Photo credit: Photo courtesy of Penray
You have likely heard the metaphor, “You are what you eat,” and interpret it as needing to eat good, healthy food for one’s body to be healthy and fit. For engines to stay healthy and fit, they must be serviced properly with quality products. Today’s advanced engine technologies can be more susceptible to premature failure and damage from contaminated or substandard products being introduced into their systems.
Therefore, it is important that fleet owners and operators be aware of potential problems and take action to protect their investment in engines by establishing a good offensive plan designed to reduce downtime and help keep fleets on the road.
Because problems that may arise with gasoline engines are usually different in nature than issues with diesel engines, it’s unlikely that there is one “magic bullet” that will protect against every problem with every engine manufacturer. Problems with diesel engines likely won’t be addressed properly using products or remedies for gasoline engines and vice versa.
Two areas where a good offensive plan especially pays off are the quality of fuel used and the antifreeze/coolant used to help protect engines. Numerous engine failures can be traced to degraded fuel or coolant quality.
PROPERTIES OF FUEL
Today’s fuels are specialized products that are made to burn cleaner and produce lower emissions. They must meet mandated regulations to help reduce atmospheric pollution. To comply with these laws, refiners must use various processes that change certain properties of fuel. After manufacture, fuel must be protected from contamination.
The presence of moisture or water in fuel, whether gasoline or diesel, can create a multitude of problems and seriously damage an engine. There are plenty of opportunities for moisture to contaminate fuel after it leaves the refinery, including through transportation, storage and handling and exposure to humidity.
Regardless of how it gets into the fuel, water causes problems and protection against fuel contamination is imperative.
Gasoline is susceptible to water contamination due to its chemistry. More than 95 percent of gasoline at the pump contains ethanol in about a 10 percent concentration. Ethanol is a compound used to oxygenate gasoline so it burns cleaner. However, ethanol readily absorbs water from its environment and high water concentrations may cause ethanol to separate from gasoline.
A concentration of ethanol and water in solution is heavier than fuel, and if introduced into an engine’s fuel tank, it is probable that fuel filters may become obstructed or the engine won’t run properly. Minimal moisture contamination can be treated with a pour-in water-removing additive.
Engines at high risk for moisture contamination, such as marine engines or those in prolonged storage, may also benefit from use of a fuel stabilizer treatment added to the fuel. Fuel stabilizers help preserve the quality and color of fuel in storage.
A COMMON PROBLEM
Water contamination in diesel fuel is a common problem. Diesel fuel holds more water in suspension than gasoline, which wreaks havoc with water separators, fuel filters and fuel injectors. Filtration is generally required at several points of distribution to help ensure water doesn’t reach the engine.
Moisture also hastens microbial and fungus contamination of diesel fuel, resulting in slime from bacteria growth. Moisture also increases solids contamination, intensifies corrosive properties and will shorten fuel filter life.
In colder climates, water in diesel fuel can freeze and plug fuel lines and filters. Moreover, a portion of diesel fuel is made of wax (paraffin) molecules. The more wax in diesel fuel, the higher the energy value. However, too much wax in fuel can cause cold temperature plugging and fuel flow problems.
In response, chemical manufacturers now produce additives that help prevent cold weather problems resulting from wax and ice, and produce biocides to fight microbial and fungus contamination. While biocides help prevent and kill bacteria and fungus in diesel fuel, use only as necessary as they may not mix well with other fuel additives.
LOW SULFUR FUELS
Diesel fuel is formulated to meet specific emission regulations also, which resulted in the introduction of ultra-low sulfur diesel (ULSD) fuel. Sulfur is an impurity that produces unwanted combustion by-products. Some diesel engine components, such as fuel pumps and fuel injectors, are lubricated by diesel fuel and sulfur to help provide lubricating properties.
Some fuel pump failures were reported when using lower sulfur diesel (LSD) fuel. A number of failures were blamed initially on the inability of the fuel to lubricate important components in the fuel system. Diesel fuel lubricity additives help lubricate and protect fuel system components from premature wear resulting from compromised lubricity of some LSD fuels.
Another problem with ULSD fuel is asphaltene (molecular substances found in crude oil). Under certain conditions, asphaltene can form into an oily, black sludge material that plugs fuel filters. The problem intensifies when moisture and heat are present.
Ultra-low sulfur diesel fuel holds more dissolved water than high sulfur diesel fuel. Biodiesel fuels (made from agricultural products) hold even more water than ULSD, so even small amounts of biodiesel fuel mixed with ULSD fuel may can increase the amount of dissolved water that may be present.
Asphaltenes appear brown and slimy and resemble microbial contamination, so it is easy to misdiagnose and treat improperly. Using thermal and oxidation stability fuel additives with moisture removal properties can help reduce this issue.
A second area where a good offense plan works is cooling system maintenance. With record-setting temperatures all across North America this past year, it’s time to focus on servicing cooling systems. After a tough season like this past summer, engines and cooling systems could use some relief. Preventative maintenance on the cooling system before winter arrives helps ensure fleets continue running efficiently.
An understanding of the difference in various antifreeze/coolants may help reduce cooling system failures that could lead to premature engine wear and failure. Most antifreeze is largely comprised of ethylene glycol as the base and contains a smaller proportion of water and additives. A small fraction of the antifreeze market uses propylene glycol as the base, but it’s usually more costly than ethylene glycol.
Generally, a 50/50 mixture of antifreeze and water are installed in the engine’s cooling system. This mixture is now termed “coolant.” Additives called inhibitors are included to protect metal surfaces and consist of different compounds, like silicates to protect aluminum, nitrates to protect iron and steel, phosphates or borates to defend against acidic corrosion, molybdates and nitrites to keep cavitation under control and other inhibitors to protect non-ferrous yellow metals like copper and brass.
As coolant is used, inhibitors deplete and may need to be replenished with Supplemental Coolant Additives (SCA), especially when using fully formulated conventional antifreeze.
Conventional antifreeze is known as Inorganic Acid Technology (IAT). To help extend intervals and “simplify” maintenance, Extended Life Coolants (ELC) have been developed. ELCs utilize Organic Acid Technology (OAT) as an inhibitor to help protect metal surfaces in the cooling system. ELCs may also contain additional inhibitors, such as nitrites, and are known as Nitrited Organic Acid Technology (NOAT). ELCs based on other types of inhibitor technology or using both IAT and OAT chemistry are known as Hybrid Organic Acid Technology (HOAT).
ELCs, which are mostly ethylene glycol-based, also require periodic maintenance just like fully formulated conventional IAT coolants. In conjunction with routine checks for proper level, leaks and freeze protection, coolant should be examined using test strips or a coolant analysis program to ensure inhibitor levels are sufficiently maintained.
While protection against freezing of a coolant mixture is important, it has little bearing on other protective properties of coolant. If SCA is needed to bring inhibitor protection back up to safe levels, ensure the proper SCA is used as there are different types of SCAs available. For example, NOAT coolant usually requires periodic use of a nitrited SCA at specific intervals to help boost the inhibitor chemistry for adequate protection throughout extended service intervals.
Some fleets may use coolant filters that not only help remove solid debris from the coolant but replenish and help maintain proper inhibitor levels.
Antifreeze comes in a rainbow of colors ranging from green to orange to yellow and every color in between. In general, green has been used for conventional, fully formulated IAT antifreeze; orange used for OAT; and NOAT and HOAT may come in red, pink, yellow (gold), purple or another color. However, never use color as a guide to selecting antifreeze.
It’s very important to know that color alone doesn’t positively identify a specific type of coolant chemistry. Antifreeze is clear and manufacturers add dye to help differentiate their products.
Equipment manufacturers specify different chemistry, not color, for good reason. While one ELC may work well in a specific cooling system, using another type of ELC may cause eventual damage to a cooling system or engine. If in doubt, follow manufacturers’ recommendations.
With all the colors and confusion surrounding ELC, a service technician must be well-informed on servicing cooling systems properly. One possible approach to simplification and reducing confusion may be to use a “universal” or “multi-vehicle” ELC and follow the antifreeze manufacturer’s instructions.
Using the correct type and concentration of antifreeze, along with recommended maintenance practices, fleet managers should be able to avoid many cooling system problems.
Joseph Long is the director of sales for the Power Fleet Division at Penray. The Penray Companies has been the standard of excellence in product quality and service for professionals for more than five decades. Penray sets the pace in cooling system treatments, fuel treatments, and shop chemicals that maximize performance and help extend vehicle life. www.penray.com.