| Cover Story The serious threat lurking in your fuel tanks As sludge builds up in diesel fuel, bits of it slough off and travel downstream where they adhere to surfaces – like the bottom of this fuel fi lter – and start to grow new sludge. Photo courtesy of Fuel Right on vehicles, particularly to the underbody and electronics, causing damage in as little as a single winter season. TMC (www.trucking.org/Technology_ Council.aspx) is the only industry association that is focused solely on truck technology and maintenance. Magnesium chloride and calcium chloride are especially destructive because they cling to the underbody of a vehicle and crystallize as they slowly dry out. Th ese crystals are hydrophilic, meaning they have a strong affi nity for water and readily dissolve in water or a watery solvent. Because they absorb moisture, the crystals remain in a semi-solution state for extended periods of time, and this multiplies their corrosiveness. By Dan Jenkins, Principal, Iron Ox It all starts when a technician notices a few drips of fuel coming from a vehicle’s tank. Typically, the search for the source of the leak begins by looking for the obvious: a loose or defective hose or fi tting. When that inspection yields no results, the next thing is to determine if the tank was hit by an object that could have caused a small puncture. Often, this inspection reveals something much worse: the tank is corroding. Fleets across the country are discovering that corrosion is a main culprit for fuel leakage. To make matters worse, a close examination will have to be made to determine if the corrosion is on the interior or exterior of the tank. In either case, this is a serious problem. It’s well known that corrosion is already a problem on brake lines, electrical connectors, frames, springs and just about every component exposed to salts used to de-ice roads. However, few fl eets consider tank or fuel system corrosion, which can occur on both steel and plastic products. SOME BASICS Let’s start out with some basics: • Corrosion – This is the process of metal being destroyed by a chemical action. • Delamination – This is a mode of failure for composite materials. A signifi cant contributor to these conditions can be traced to the changes in fuel resulting from both the Renewable Fuel Standard and Energy Independence and the Security Act of 2007 which mandated signifi cant changes in fuel. The most agreeable cause is the increased acetic acid in fuel produced by microbes which produce aggressive action on components. INTERIOR TANK CORROSION The biggest culprit for interior tank corrosion is pitting corrosion – a localized form of corrosion wherein cavities (small holes) are produced in a material. Pitting is considered to be more dangerous than uniform corrosion damage because it is more diffi cult to detect, predict and design against. Pitting corrosion is often found where there are high degrees of sludge in fuel fi lters with Ultra Low Sulfur Diesel (USLD) and metal tanks. Pitting occurs when water, fuel and bacteria combine to create sludge. Water and associated acids will get trapped behind the sludge and form the perfect habitat for pitting corrosion. If you suspect internal fuel system corrosion, a good place to start is to cut open your fuel fi lters. If you observe debris that looks a lot like black coffee grinds or fi nd rust chips the size of your fi ngernail, then you most likely have corrosion problems somewhere in your system. TREATMENT OPTIONS One treatment for internal fuel tank and system corrosion is the use of EARLY DETECTION of problems is paramount. MOBILITY ADJUSTRITE® ESTIMATING DELIVERS UNRIVALED With touch screen ease, you can create professional collision repair estimates on the spot using a web-enabled tablet or smartphone. FREE TRIAL OFFER No credit card required and no sales calls! We’re confident your first estimate will convince you this is the estimating tool you’ve always needed. Visit adjustrite.com to get started. VehicleServicePros.com/10226485 12 FLEET MAINTENANCE ❚ AUGUST 2016 ❚ VehicleServicePros.com
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