What is the main purpose of crankcase ventilation?
2 Answers
The main purposes of crankcase ventilation are: 1. To prevent engine oil from deteriorating. 2. To prevent leakage from the crankshaft oil seal and crankcase gasket. 3. To prevent various oil vapors from polluting the atmosphere. 4. To prevent excessive crankcase pressure, extend the oil change interval, reduce component wear and corrosion, and prevent engine oil leakage, crankcase ventilation is necessary. When the engine is running, some combustible mixture and exhaust gases leak into the crankcase, which can dilute the oil, degrade its performance, and reduce lubrication effectiveness. If the exhaust gases contain water vapor and sulfur compounds, they can form sulfuric acid, leading to corrosion of engine components. Therefore, crankcase ventilation is essential.
The crankcase ventilation system primarily prevents excessive internal engine pressure and protects the environment. During engine operation, piston movement allows combustion gases to leak into the crankcase. If these gases aren't vented, pressure builds up, potentially damaging oil seals and causing oil leaks or dilution. Diluted oil loses lubricating effectiveness, accelerating engine wear. Additionally, these gases contain unburned fuel and pollutants. The ventilation system recirculates them into the intake for re-combustion, reducing harmful emissions to meet modern environmental standards. As a mechanic, I've seen numerous cases where clogged vents caused dramatic crankcase pressure spikes - oil caps blown off, coating the entire engine bay in messy oil spills that are costly to clean. Regular inspection of the PCV valve and hoses is crucial to prevent minor issues from escalating into major repairs. Simply put, proper ventilation makes engines more durable and cleaner while doing our part for the planet.
