Clearing up concerns about diesel fuel contamination
By Steve Temple
Keeping your pickups running reliably starts with the three Cs: clean air, clean oil and clean fuel. We’ll focus on the latter aspect in this article, as dirty diesel fuel can be catastrophic for an engine and costly to your company’s bottom line. As durable and powerful as today’s diesel pickup engines are, their Achilles’ heel is the fuel. If it’s “off spec,” there’s going to be a price to pay.
SAE studies indicated that as much as 70 percent of filling-station diesel doesn’t meet design standards of OE engine manufacturers, especially in the area of lubricity.
One distributor we contacted (who asked to remain anonymous), sees variances in fuel quality as often as once a month. These variances can be caused by different sources of crude, types of refining processes, seasonal changes in formulations – and how the fuel is stored.
That’s why David Johnson, Manager of Auto Services for Clark County, NV, flushes his storage tanks at least twice a year.
Since he’s responsible for keeping nearly 2,700 municipal vehicles operational (35 percent of which are diesel pickups), he says, “It’s imperative to clean the tanks. You never know what’s in there, especially if they’ve been run dry, and there’s residue in the bottom.” He also adds filters to the pumps, as fine as three microns, which are replaced every 30 to 60 days.
Even a small amount of fuel contamination can lead to major engine work. Injectors under today’s high pressures don’t like water. Neither do pistons.
Erik Bjornstad of Bell Performance, a leader in additives to resolve fuel contamination problems, says cross contamination of ethanol blends with diesel in the distribution system are a major culprit. When there’s “phase separation” in the ethanol (caused by the presence of water), microbes can grow inside a storage tank.
“Acetobacter, a strain of bacteria, produces acetic acid that cause corrosion,” Bjornstad points out. It can clog filters and leave deposits in the fuel system and engine components, causing several mechanical problems.
Bjornstad agrees with Johnson about the importance of annual and even semi-annual cleaning of storage tanks by commercial “fuel polishers”, but notes that it’s important to determine whether they incorporate a biocide or not to kill off the bacteria so it doesn’t return. Another potential source of contamination might be from biodiesel that hasn’t been refined properly.
“Incomplete transesterification [of a biodiesel feedstock] produces free alcohols that are very corrosive,” notes Peter Gunnerman of Advanced Refining Concepts which makes GDiesel, a new type of diesel refined with natural gas. He feels that the biodiesel industry in general is unregulated, with inconsistent product quality.
Bjornstad and other fuel experts agree about the potential problems with biodiesel in the area of fuel contamination and bacterial growth, depending on the producer and feedstock used.
Even a tiny bit of debris in fittings or fuel can require a complete engine teardown and expensive injector replacement.
(If you want to have your fuel checked, contact Southern California Biofuel, 888-888-4121. Biodiesel companies know all about testing for cloudiness/contaminants.)
If your fleet doesn’t have centralized fuel storage, what else can you do to ensure a clean fuel supply? Whether a diesel or gas pickup, Johnson changes his vehicles’ fuel filters every six months or 5,000 miles, whichever comes first. “Filters are cheap insurance,” he points out.
Not all filters are created equal, though. While Johnson sticks with the factory units so he doesn’t run into any potential warranty problems, Filter Solutions Technologies (FST) notes that some vehicle manufacturers don’t even have an engine-block filter.
FST’s Rick Rollins claims its low-restriction FloMax300 spin-on filter can handle ethanol, and has a “quiet zone” for settling of contaminants, along with water shedding (not water blocking, which can cause the filtration media to swell). He points out that OE filters can trap particles as small as 15 microns, but FST goes down as fine as three microns, depending on the unit.
In addition to good filtration, certain types of fuel additives can be of value as well in treating ethanol blends.
While Bell Performance offers Ethanol Defense (the company’s most popular product), Bjornstad acknowledges that there are many others on the market, and recommends using only those that don’t have alcohol in them, in order to handle water properly (especially in portable equipment with small engines, which are not as resistant to alcohol as the drivetrain engines in late-model pickup trucks). “These additives should also have detergency, combustion improvement and protectants,” he points out.
Another concern with ethanol blends involves mixing them with certain fuels that have an older type of octane enhancer: MTBE. While this toxic chemical is far less common than it once was, it’s still found in off-road or marine fuels. If they are combined with an ethanol/gas blend (say, in a jug used to refill the tank of a generator or chain saw), Bjornstad says a brown sludge or residue can form and cause mechanical problems.
How can you determine if your fuel is contaminated? A visual inspection will reveal a lot, showing discoloration, cloudiness, or separation of liquids and particulates. Of course, a plugged filter is also a good indicator there’s a big fuel problem.
Whatever the symptoms of fuel contamination, they should not be ignored; bad diesel fuel will invariably lead to serious [costly] damage to both the truck’s fuel system and engine. And small fuel contamination issues escalate very quickly to major problems.
EGR SYSTEM CLEANING TIPS
Everybody complains about the weather, but nobody does anything about it. Some might say the same thing about carbon buildup on the EGR valves and induction systems of older diesel trucks.
Clogged EGR valves and manifolds are a primary cause of poor performance and fuel economy.
Cleaning the EGR valve and manifold is both dirty and time consuming—but worth the effort. It should be done at lest once every 100,000 miles.
You can take one of two Âapproaches: chemical or physical cleaning.
On the chemical side, BG Products has a cleaner that is said to work well. It requires pulling out the intake hose and EGR valve, installing a block-off plate on the intake, and using a special adapter with an injector where the EGR valve normally is located to run a bottle of the treatment through the fuel system.
Then the injector is moved to the intake side and another bottle of cleaner is run through the engine.
Total time for the chemical cleanout is about 1-1/2 hours, after which you run BG’s oil flush/treatment and do an oil/filter change.
Of course, the “old school” method of cleaning the EGR system is to carefully pull the valve and intake manifold off the engine, and clean both by hand. (See “EGR Manifold Cleaning” on our website.)
Use carb cleaner, a screwdriver and wire brush to get rid of the carbon buildup. Then soak the valve in carburetor cleaner (but not brake cleaner, as that can damage the O-rings) before reassembling.
