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.