Bottom Line
Fuel School
Diesel dosing
Additives remedy a number of diesel woes and have a place in your operation year-round

By Paul Abelson
senior technical editor

Virtually all truckers use diesel additives, mostly in the winter, to prevent gelling and to manage water. While only a relative few use them all year, your operation may be one that needs year-round help.

Geography, climate and operations differ. All of these things affect your need to use additives.

Little is done to differentiate one brand of diesel from another. Promotion is about the truck stop, not the fuel. Companies use the same pipelines. They take out in proportion to what they put in. With very few exceptions, it doesn’t matter which company refined what.

Diesel starts to deteriorate as soon as it’s refined. The longer it takes to get from the refinery to your engine, the worse its condition. Air oxidizes diesel. Bacteria and fungi thrive in it. Water condensed from air promotes organic growth, which clogs filters and contaminates fuel systems.

Pipeline companies transport diesel in bulk. It is treated with only enough additives to protect the pipelines. Truck stops with high volume sales don’t have diesel in their tanks long enough for it to deteriorate.

But, some truck stops that sell on price alone often buy surplus fuel or fuel that has been stored too long. Some cut costs on housekeeping by not removing sludge, slime and water.

Winter brings starting problems, ice and gelling. All ultra-low sulfur diesel contains more paraffinic molecules that join when temperatures drop. The wax binds the fuel into a gel-like mass. Even before the fuel gels in the tank, the wax will plug fuel filters, blocking flow and literally stopping the engine cold.

Water can collect in fuel lines and freeze, restricting or blocking fuel flow.

Soot and varnish deposit on injector nozzles. The buildup alters spray patterns, causing more incomplete combustion in a cycle that causes more and more injector clogging.

Additives counter these common fuel problems. Not all have the same balance of ingredients, so each acts differently.

It’s up to you to read labels and determine which works for you. Requirements vary geographically, and results will vary according to dosage. Always read labels. Don’t overdose.

Additives control water year-round. Emulsifiers suspend tiny droplets that pass through the fuel system. De-emulsifiers alter diesel so it won’t hold water, so water drops to the bottom of the tank. Water should be removed regularly. Controlling water also helps control organic growth.

Biocides in some additives kill organic growth – the bacteria and fungi. Always read and follow label directions precisely. Biocides are highly toxic.

Almost all additives have detergents that cut through soot and varnish buildup and maintain or restore injector spray to design specifications. The detergents also dissolve any varnish or gum buildup in combustion chambers.

Additives previously contained lubricants to replace lost lubricity. Some still do, but today, all diesel meets lubricity standards set in 2005. Less than 2-percent biodiesel can provide all lubricity needed to meet the standards.

Fuel can be improved using additives year-round. Good fuel can be made to perform better by keeping engines cleaner longer.

Your engine needs fuel that resists gelling in winter, and water and organic growth should be controlled all the time. It needs detergents all year, so even in summer, additives will keep your engine operating better longer. Additives are most important in winter’s cold, but they improve engine performance all year long.

Paul Abelson may be reached at truckwriter@anet.com.

July Digital Edition