System Operation
As the engine runs, high pressure gases are contained within the combustion chamber. Piston rings seal against the cylinder preventing the high pressure gases from passing into the crankcase between the side of the piston and the cylinder bore. Some amount of gas always leaks past the piston rings into the crankcase. If this blow-by gas could not escape, pressure would build up within the crankcase. The CCV oil separator pulls oil out of the blow-by gas and delivers the blow-by gas back to the intake system.
It is critical to keep the parts of the CCV system clean and open; otherwise gas flow will be insufficient. A plugged or malfunctioning CCV system eventually damages an engine. A poorly maintained CCV system eventually becomes contaminated with sludge, causing serious engine problems.