Oil in the air FILTER of your car? Solution

On some occasions when changing the air filter of your car you will notice that the air filter has an oil stain.
This oil in the car's air filter comes from the engine, when the engine oil is heated by its normal operation, then it vaporizes and goes out through the hoses of the crankcase ventilation system, the PCV valve must allow this oil vapor is carried to the intake manifold and burned in the engine's combustion chambers.
If the PCV valve sticks or works intermittently then the engine oil continues to the air filter through the hoses of the PCV system.
The air filter must be changed as well as the clogged PCV valve, you can also try cleaning it with hot water and degreaser.
Changing the PCV valve and air filter cost about $10 (Ten dollars total, Five Dollars each).