The platform strategy pursued by vehicle manufacturers leads to many engine variants. Using the option of parallel operation of the ProVent2 100 to 300 or simply the extendibility of the ProVent2 500, the system can be adapted to different volume flow rates and also to different requirements regarding pressure difference and the service interval. While the market volumes for the ProVent² 100 to 300 are high enough to justify a plastic housing, the market for large engines is characterized by lower volumes. In order to cover different power classes and application-specific load profiles with an appropriate efficiency, MANN+HUMMEL has in addition developed a modular crankcase ventilation system made from die-cast aluminum. As a result, the modular designed ProVent² 500 variant for engines in approx. the 2,500 kW power class consists of three parts. Each part again consists of two parts: a basic module and a separation and control module. The basic module has flow channels for the dirty gas loaded with oil droplets, the clean gas and the return of the separated oil. Depending on the engine size, a number of these basic modules can be easily mounted one after the other. The actual coalescer is positioned on the basic module. The dirty blowby gas enters the basic module from below into the coalescer and flows through it from the inside to the outside, whereby the aerosol is separated with high efficiency by the filter media. The separated oil then flows through the oil return channel back to the oil sump of the engine.