How the Crankcase Filter Keeps Your Ram 2500 6.7 Cummins Running Strong The crankcase filter in your Ram 2500 6.7 Cummins diesel engine plays a critical role in maintaining clean airflow and reducing harmful emissions. It filters out oil vapors, soot, and blow-by gases that escape from the combustion chamber into the crankcase. Without this filtration, contaminants can re-enter the engine’s...