EGR units call for stringent diesel oil specs

API CI-4 and Mack EO-N Premium Plus specifications indicate demand for higher quality diesel oils.

New Environmental Protection Agency (EPA) pollution regulations, which require a 50% reduction in diesel emissions, are set to go into effect in October. Engine manufacturers have answered this mandate with exhaust gas recirculation (EGR) units, which recirculate a portion of the exhaust to the engine's combustion chamber to incinerate pollutants. These EGR units have a significant impact on the engine oil, prompting the American Petroleum Institute (API) to take them into consideration for its next diesel oil performance specification, CI-4.

The main drawback associated with EGR-equipped engines is the high level of soot introduced in the engine. These high soot levels can lead to higher soot related wear, as well as increases in oil viscosity. EGR is also expected to negatively affect engine operating temperatures, oil oxidation and cold start pumpability.

API CI-4 diesel oils are expected to provide optimum protection for EGR engines, as well as be "backward compatible" for existing engines.

Areas directly addressed in CI-4 include "corrosive and soot related wear tendencies, piston deposits, degradation of low and high temperature viscometric properties due to soot accumulation, oxidative thickening, loss of oil consumption control, foaming, degradation of seal materials and viscosity loss due to shear."

AMSOIL 15w-40 Synthetic Blend Diesel Oil, 15w-40 Synthetic Heavy-Duty Diesel Oil and Series 3000 Synthetic 5w-30 Heavy-Duty Diesel Oil are recommended for and provide superior lubricating protection in both EGR-equipped and non-EGR- equipped diesel engines for extended drain intervals.

In order to assure top performance in EGR-equipped engines, some equipment manufacturers have released their own tough engine oil performance specifications.

Currently, the Mack EO-N Premium Plus High Performance Diesel Engine Oil specification is the most stringent in the industry.

According to Mack's service bulletin, "EO-N Premium Plus oil provides a higher oil film thickness, better wear performance, and improved oxidation control at higher oil temperatures.  These oils will also hold a greater amount of combustion soot in suspension."

Effective resistance to soot and oxidation were high priorities in setting the Mack EO-N Premium Plus specification.  The Mack T-10 Test measures oxidation resistance of the oil at higher temperatures and its ability to control abrasive wear, as well as cylinder wear and bearing corrosion protection.  It is the most severe test of this type in the industry.  The Mack T-8E is a severe 300-hour test that measures an oil's ability to resist soot-related thickening.

AMSOIL 15W-40 Synthetic Blend Diesel Oil (PCO) is on the Mack EO-N Premium Plus approved oils list.  Both AMSOIL 15W-40 Synthetic Blend Diesel Oil and AMSOIL 15W-40 Synthetic Heavy-Duty Diesel and Marine Motor Oil are superior quality oils recommended in applications specifying Mack EO-N Premium Plus lubricants.

While conventional diesel oils are often unable to effectively disperse soot and maintain their viscosity, the superior synthetic base stocks and advanced additive packages of AMSOIL Synthetic Diesel Oils effectively control the increased soot and acid levels associated with EGR units, maintaining viscosity and providing unsurpassed wear protection for extended drain intervals.  AMSOIL Synthetic Diesel Oils effectively reduce both lubrication expenses and pollution by extending drain intervals, reducing downtime and keeping emissions to a minimum.