The positive crankcase ventilation or PCV valve.
Quote:
All automotive engines are lubricated with oil and when oil is churned by moving parts, pressure is produced. Piston rings and valve guides also leak slightly producing pressure in the crankcase. Many years ago, they simply vented the pressure into the atmosphere with a road-draft tube and breather cap. Today we use a positive crankcase ventilation or PCV system to handle this and other task.
How the PCV system works
The PCV system is relatively simple. An inlet hose connects to a filtered air source. This is used to supply clean air that is drawn though of the engine. Most of the time this air is supplied through the engine air filter. On a few designs there is a separate inlet filter that cleans the incoming air for the PCV system only. This filtered air flows through the engine, picking up fumes and vapors. The air exits through another hose, connected to manifold vacuum. The flow of air draws fumes from the crankcase and burns them harmlessly in the engine. This also creates a slight vacuum, relieving any pressure that may build. Negative pressure helps to prevent oil leaks and oil consumption by the engine. The PCV valve also helps regulate the amount of air flow, which helps prevent oil being drawn out of the engine.
Quote:
It is also one possible cause of expensive oil leaks and sludge buildup in an engine.
For me and my 2000 Dodge Neon, it's the only thing that makes me repeatedly top off my motor with new oil. So much so that I can't even go a full OCI because of it being a Design Flaw.
Edit: a word
Quote:
All automotive engines are lubricated with oil and when oil is churned by moving parts, pressure is produced. Piston rings and valve guides also leak slightly producing pressure in the crankcase. Many years ago, they simply vented the pressure into the atmosphere with a road-draft tube and breather cap. Today we use a positive crankcase ventilation or PCV system to handle this and other task.
How the PCV system works
The PCV system is relatively simple. An inlet hose connects to a filtered air source. This is used to supply clean air that is drawn though of the engine. Most of the time this air is supplied through the engine air filter. On a few designs there is a separate inlet filter that cleans the incoming air for the PCV system only. This filtered air flows through the engine, picking up fumes and vapors. The air exits through another hose, connected to manifold vacuum. The flow of air draws fumes from the crankcase and burns them harmlessly in the engine. This also creates a slight vacuum, relieving any pressure that may build. Negative pressure helps to prevent oil leaks and oil consumption by the engine. The PCV valve also helps regulate the amount of air flow, which helps prevent oil being drawn out of the engine.
Quote:
It is also one possible cause of expensive oil leaks and sludge buildup in an engine.
For me and my 2000 Dodge Neon, it's the only thing that makes me repeatedly top off my motor with new oil. So much so that I can't even go a full OCI because of it being a Design Flaw.
Edit: a word
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