Why Does Diesel Fuel Need Additives?

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AMSOIL Diesel Fuel AdditivesAMSOIL Diesel Injector Clean
by Joel Youngman
June 5, 2023

Adequate diesel fuel lubricity is essential for protecting the precision components in modern diesel engines. This is especially true for high-pressure common-rail (HPCR) engines, where increased wear and deposits can interfere with an optimum spray pattern, reducing power and fuel economy. Find out how to keep your diesel engine running strong all year long with premium diesel fuel additives.

Less lubricity

Diesel fuel traditionally had high lubrication properties, but the desulfurization process that helps diesel fuel meet modern ultra-low-sulfur diesel (ULSD) requirements also strips it of the organic compounds responsible for lubrication. Although the ASTM D975 standard for diesel fuel provides a minimum level of lubricity, it’s not as much as the Engine Manufacturers Association (EMA) recommends.

To meet stringent government mandates for reduced emissions, nearly all diesel fuel sold in North America today is ULSD, which contains a maximum of 15 ppm sulfur. Compare that to as much as 5,000 ppm in traditional diesel fuel available prior to EPA regulations taking effect in 2006. Additionally, ULSD is compatible with modern exhaust treatment devices, such as diesel particulate filters (DPF), that further assist in emissions reduction.

The solution to ULSD

The best way to increase fuel lubricity is to use a fuel additive designed specifically for this purpose, like AMSOIL Diesel Injector Clean, Diesel Injector Clean + Cetane Boost, or Diesel All-In-One, which combines the benefits of AMSOIL Diesel Injector Clean, Diesel Cold Flow and Diesel Cetane Boost in one convenient package.

AMSOIL diesel fuel additives also provide additional benefits designed to keep diesel engines operating at their maximum performance.

Diesel Injector Clean

The concentrated formula lubricates to reduce fuel pump and injector wear and rapidly targets and eliminates accumulated nozzle deposits, combustion-chamber deposits and internal-diesel-injector deposits found in HPCR injectors to maximize horsepower and increase fuel economy up to 8%.

Diesel Injector Clean + Cetane Boost

Combines the superior deposit-removing properties of Diesel Injector Clean and the cetane-boosting benefits of Diesel Cetane Boost in one convenient package that delivers outstanding detergency, reduces smoke and emissions, improves lubricity and increases cetane and horsepower.

Diesel All-In-One

Combines the superior detergency of Diesel Injector Clean, the excellent anti-gelling properties of Diesel Cold Flow and the increased cetane benefits of Diesel Cetane Boost in one convenient package that helps remove deposits and improves lubricity, cold flow and horsepower.

AMSOIL Diesel All-In-One is proven to improve diesel fuel lubricity and protect against injector wear based on independent ASTM D6079 testing.

Diesel fuel lubricity is essential for the protection of modern diesel engine components. Keep your engine operating at peak performance with AMSOIL Diesel fuel additives.


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by Joel Youngman

AMSOIL Lead Technical Writer for more than two decades.

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AMSOIL Diesel Fuel AdditivesAMSOIL Diesel Injector Clean