Clean Air legislation is affecting the way that Americans work, live and view the future. As America’s consumption of diesel fuels continues to increase, it is a necessity to dramatically reduce the pollutants resulting from the use of every gallon of fuel. The EPA has mandated a series of emissions reductions in diesel engines. These progressive reductions are required in 2002, 2004 and 2007. Ultimately, the 2007 standards represent a 90% reduction in NO-2 and an 80% reduction in particulate mater (PM). The timeline was accelerated by the October 1998 consent decree involving the diesel engine OEM’s, EPA and Federal Department of Justice.

Significant changes to diesel fuel and to diesel engines will both be necessary to achieve the emissions reductions. One of the changes to the engines may include the addition of exhaust gas recirculation (EGR) devices. The EGRs will be cooled in the standard coolant system, by the engine coolant. In some experiments, the heat from these systems has been associated with premature aging of the coolant. Of special concern is the degradation of the base antifreeze chemistry, ethylene or propylene glycol. Additive packages are also aging by oxidation faster than is normally observed in engines not equipped with EGRs.

At this time, the 2002 / 2004 / 2007 coolant behavior data is extremely young, in research terms. Continuing efforts to quantify the recently discovered behavior and to understand the possible effects of the accelerated aging are underway.