The 3516B Auxiliary/Generator Set Engine incorporates a separate circuit aftercooling (SCAC) or sea water aftercooling (SWAC) system for all configurations. The primary advantage of the SCAC systsem is reduced aftercooler corrosion since no sea water circulates through the aftercooler. Many other improvements on these engines contribute to minimizing owning and operating costs. A strengthened fuel injection actuation system and rear gear train maintain reliability and durability while providing higher injection pressures. The 3516B also features thermo-laminated heat shields on all marine configurations to maintain surface temperatures below Marine Classification Society regulations.