20 Fleet Maintenance | April 2017 » Test strips are a simple and effective onestep way to help quickly identify additive levels and water condition. They can be used in the field and with scheduled maintenance. Photo courtesy of Prestone In 1994, Caterpillar released its EC-1 coolant specifi cation for NOAT coolant. Th e specifi cation was for a 150,000 miles or 3,000-hour coolant that could be extended to 300,000 miles or 6,000 hours with the addition of an extender. Th en, in 1999, Caterpillar extended the service life specifi cations for NOAT coolants to 300,000 miles or 600,000 miles with an extender. During this period, many OEMs moved away from IAT in favor of NOAT technology and extended life formulas. Increased Pressures In response to the rising cost of fuel and growing environmental concerns, the next decade brought increased pressures to improve emissions and obtain a higher fuel economy. To achieve these results, signifi cant design changes were needed to both vehicles and engines. Lighter materials were used to build engines and cooling systems, including a move from copper/brass to aluminum radiators. Initial aluminum radiators were manufactured by either assembly lines or through a vacuum brazing process. Th en, a new process, controlled atmosphere brazing (CAB), was developed to improve effi ciency. It paved the way for increased production, but with some unforeseen issues. Th e CAB process leaves behind varied levels of residual brazing fl ux on the aluminum surface, which can react with certain coolant inhibitors. One important inhibitor aff ected by CAB is nitrite, the key inhibitor used to protect liners from cavitation damage. As a result, fl eets began to experience a quick decrease of nitrite concentrate with a pH spike in their coolants, accompanied by an increased corrosion rate on aluminum cool system components. Th is increased corrosion led to the disbursement of aluminum corrosion byproducts throughout the cooling system, causing signifi cant cooling system problems and buildup in coolant fi lters. While vehicles with copper/brass radiators don’t have this issue, vehicles with CAB brazed aluminum radiators were left vulnerable. A Shift Creates Confusion Heeding concerns that NOAT wasn’t providing the same level of protection for aluminum systems, a number of OEMs changed their factory fi ll coolant from NOAT to nitrite free extended life coolant (NF OAT). Navistar has been factory fi lling some engines with NF OAT since 2010. In 2016, Detroit Diesel announced a move to NF OAT coolant. Cummins is currently qualifying NF OAT coolants for its engines. While these changes from NOAT to NF OAT eliminate issues caused by nitrites, it opened Coolants Go Colorblind Even after moving from NOAT (Nitrite Organic Acid Technology) to NF OAT (nitrite free extended life coolant), some heavy duty OEMs have kept coolants the same color. Unaware of the change, fleets have been incorrectly mixing coolant technologies, potentially putting their fleets’ cooling systems at risk of a drop in protection against corrosion and cooling system failures. While some manufacturers do an exemplary job of differentiating coolants with color and cooling system stickers, color alone is no longer the definitive measure by which to identify a fluid type. If an AF/C (antifreeze/ coolant) type isn’t known, the fluid should be tested immediately to determine its exact technology to avoid damage and the correct coolant technology to use. CONTAMINATION What makes the issue around color dyes even more complicated is that these coolant technologies are not completely compatible. Therefore, cross contamination can cause additional corrosion problems. Conventional IAT (Inorganic Additive Technology) requires the periodic addition of nitritecontaining supplemental coolant additives (SCA) in order to maintain effective corrosion protection. NOAT requires an “extender” to maintain the correct inhibitor levels. Technicians have continued to add SCA and spin on filters that release inhibitors to what they believe is IAT, but are actually NOAT or NF OAT formulas. To further complicate this is the misuse of OAT extenders into the various coolant technologies. All of these combined issues have created a growing need for skilled technicians to identify AF/C technologies in order to properly maintain fleet cooling systems. Illustration courtesy of Prestone Confusion around AF/C color creates problems.
FleetMaintenance_April_2017
To see the actual publication please follow the link above