Fuel systems should get a good spring cleaning

By on March 8, 2011
RoadKing Mag

It’s been a long, cold winter, and we’re all glad it’s behind us. Spring is the time when the trees begin to bud, the grass turns green again and our fuel system problems are done for another year.

But are they? Gelling and icing are no longer an issue, but warmer weather can bring its own set of fuel system problems. Some involve the fuel itself and others involve the system that takes diesel from the tank and delivers it to the engine. Let’s look at what you can do to maintain your system, starting with the hardware.

First, check fuel hoses and fittings. Changes in temperature cause clamps to loosen. If they do, hoses vibrate. Check hoses for splits and cracks. Make sure the hoses are seated on their fittings. If clamps need replacing, don’t get the inexpensive ones that use spring pressure or ones with slits for the worm screw. They can damage the hose if tightened too much. The best ones are temperature compensating, constant torque clamps. They are smooth all the way around the hose. They have a spring next to the adjustment screw to maintain clamping force as temperatures vary.

Springtime is a good time to change filter elements that may have been damaged by ice or clogged with organic slime or gelled fuel. Drain the water from the fuel-water separator, then, being careful not to spill any diesel, drain any fuel according to manufacturers’ instructions. You can then safely change the filter element if needed. Some fuel-water separators, like DAVCO’s, are constructed so you can visually note how much of the filter is clogged and how much life is left in the element.

Diesel fuel is a breeding ground for organic growth. Fungus and bacteria take nourishment from hydrocarbon fuel and oxygen from water that has condensed in the tanks when temperatures cool at night. The interface where the diesel floats on accumulated water is where you’ll find the slimy organic colonies. Drawn into the fuel intake, these organics can plug filters and stop a truck dead in its tracks.

Each spring, drain or siphon each tank until you see only clear fuel. If the amount of organic growth is excessive, treat your next tank of fuel with a biocide made for the purpose. Don’t mix the biocide with your regular-use fuel treatment, since there may be incompatibilities. Biocides are very toxic and all of the directions printed on the label must be followed.

Many drivers use fuel conditioners only in winter to control water and ice and to prevent gelling (wax molecules joining together when cold to solidify diesel fuel). But fuel needs treatment year round.

Detergents and dispersants control the formation of deposits that could affect fuel system components, including injector tips. They also control water that condenses from the air in the tank or that could enter during refueling. Most emulsify the water, keeping it separated in tiny droplets that pass harmlessly through injectors. Some conditioners de-emulsify the water, making it harder for the fuel to suspend it. The water then falls through the fuel and collects at the bottom of the tank where it can be easily removed.

Fuel conditioners, also called additives and treatments, have ingredients that perform other functions.

Lubricity improvers help lubricate internal fuel system components including pumps and injectors. They were essential to prevent failures when sulfur was removed to make ultra-low sulfur diesel. Today, the lubricity provided by biodiesel blends of 2 percent or more is enough to satisfy lubrication requirements.

Cetane improvers, once needed for easy starting, are not as important with good quality fuel. Foam inhibitors, corrosion inhibitors and stability improvers that prevent fuel from oxidizing are important additives year round.

One of the best things you can do to maintain your fuel system is to purchase fresh fuel. That means buying from trusted retailers.

Fuel in storage, whether in your truck’s tanks or in underground storage tanks, begins to degrade almost immediately after being refined. Microbes move in and form sludge. Fuel exposed to air oxidizes. Discount fuel is sold at reduced prices because it is old. It’s usually been in storage somewhere.

Diesel from a reputable, high-volume supplier is fresh. It doesn’t have time to deteriorate. It may cost a few cents more, but quality diesel could save you thousands in avoidable fuel system repairs.

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