John,
There is almost always a certain amount of condensate that collects in the 'air' side of these vertically-oriented Cummins SWAC's. That ring is likely the level of the water that collects in that engine. The inlet from the turbo is located at the bottom of the housing just at/above that ring. When the engines run, any water in the aftercooler is drawn/blown into the engine. It sounds horrible, but it is essentially just humid air by the time it hits the intake ports. The latest Cummins aftercoolers even have a condensate drain port drilled at the very bottom of the housings.
__________________
Larry
M/V Pelago
|