Crankcase Breather Hose

The Genuine BMW crankcase breather hose is a vital part of your vehicle's positive crankcase ventilation (PCV) system. This hose is responsible for channeling pressurized air from the engine's crankcase to the air/oil separator, also known as the PCV valve. The PCV valve captures and removes oil vapors from the crankcase air, allowing them to drain back into the engine. The purified, pressurized air is then directed to the intake side for normal combustion. This process is essential because engines naturally develop positive crankcase pressure as a byproduct of combustion. Due to the combined factors of pressure, heat, and the air/oil vapor mixture, the crankcase breather hose is a common failure point in the PCV system and directly impacts engine performance and emissions compliance. Symptoms of a failing crankcase breather hose can include cracks, leaks, or breaks due to constant exposure to oil vapors, heat, and pressure. The engine oil can degrade the hose material over time, leading to air leaks. Broken connectors are also common, as plastic components can become brittle. A damaged hose may present with a visible hole or split. These issues can trigger a Check Engine Light for air intake leaks or airflow-related trouble codes, cause engine misfires, rough running, and may result in oil residue on or around the hose and adjacent components, sometimes accompanied by a burning oil smell. This Genuine BMW part is manufactured in Germany and meets BMW's stringent standards for quality and performance, ensuring it is the same quality as the original parts used to build your vehicle.