The crankcase ventilation filter is a key component in the positive crankcase ventilation (PCV) system, mainly responsible for filtering and cleaning the gas that enters the intake system from the crankcase

If there is a problem with the crankcase ventilation filter or PCV valve, there will be some common and unique "distress signals"

fault phenomenon
Significant increase in oil consumption
Engine idling shaking or instability
Engine acceleration is weak
Valve cover or oil seal leaking oil
Premature deterioration/emulsification of engine oil

Possible reasons
The clogged filter prevents the condensation and backflow of oil vapor, which is directly sucked into the cylinder for combustion.
The PCV valve is stuck in the normally open position, causing additional air to enter without metering and resulting in a lean mixture; Or the filter may be partially clogged, resulting in poor ventilation.
The intake system may experience a mixture imbalance due to filter blockage or PCV valve malfunction.
PCV valve blockage and failure, high pressure in the crankcase, causing oil to be squeezed out from weak seals such as valve cover gasket and crankshaft oil seal.
A large amount of water vapor and blow by gas condense in the crankcase, and the PCV system cannot effectively discharge them.

potential harm
Burning engine oil, carbon buildup on spark plugs, blockage or failure of three-way catalytic converters.
Abnormal combustion, worsening emissions, and illuminated emission lights (OBD fault code).
Decreased power and increased fuel consumption.
Oil leakage, external dirt on the engine, and the risk of insufficient oil.
The lubrication performance of engine oil decreases, exacerbating internal wear of the engine.

Severely clogged filters or malfunctioning PCV valves may cause excessive crankcase pressure, which may be one of the culprits for oil leakage in valve cover gaskets, crankshaft front and rear oil seals, and other areas.