What is a car PCV valve?

[PiperLee]

PCV valve is a metering control valve. The PCV valve consists of a valve body, valve, valve cover, and spring, and cannot be disassembled. The PCV valve is installed between the engine crankcase ventilation system and the intake system, playing a crucial role in motor vehicles. If the PCV valve is damaged, the operation of the motor vehicle will be affected. The main function of the PCV valve is to direct gases from the crankcase into the intake manifold through the PCV valve, with a small amount of air entering the intake manifold directly from the air filter via the PCV valve. This helps prevent phenomena such as icing at the throttle and incomplete combustion, while also preventing blow-by gases from entering the atmosphere and avoiding oil deterioration. A damaged PCV valve can lead to white smoke from the exhaust pipe, accelerated wear, unstable idle speed, and in severe cases, engine idle shaking, weak acceleration, excessive oil consumption, and difficulty starting the car. The method to check the condition of the PCV valve is to clamp the hose between the PCV valve and the vacuum source while the engine is idling. If the engine speed drops by 50r per second or more, it is considered normal.