Each engine is equipped with crankcase ventilation, during operation gases develop that need to be discharged.

Initially, these released gases were directly blown into the atmosphere, but it was realized that this was not beneficial for the environment, so the engines had to become more environmentally friendly, with the air filter serving as a filter.

The crankcase ventilation is not only a discharge channel but also a breathing channel. When filtering the incoming air, the engine is protected from pollution.

The hose running from the crankcase ventilation to the air filter will eventually dry out, causing hairline cracks that will lead to leakage. Disconnect the hose and pinch it closed if hairline cracks occur in the edges, it is time to replace the hose.

The preformed hoses are only used for crankcase ventilation. The hose delivered per meter is also used as a vent hose for the fuel tank and for vehicles equipped with an absorption carbon filter (which filters the released fuel vapors).