When the engine works normally, a part of combustible mixture and exhaust gas will always leak into the crankcase through the gap between the piston, piston ring and cylinder wall. These gases have high temperature and carry fuel molecules and other impurities, and the engine oil will gradually oxidize, deteriorate and dilute at high temperature.
These gases entering the crankcase will increase the pressure in the crankcase and cause oil leakage failures such as gaskets and oil seals, so the gas leaking into the crankcase must be discharged in time. Therefore, in early engines, there was a device called crankcase ventilation device.
Extended data
It is very important to check the check valve in the crankcase forced ventilation device equipped with the check valve. What if the check valve gets stuck? If the crankcase is directly opened or blocked, the normal ventilation of the crankcase cannot be guaranteed. When the valve is stuck or blocked, the engine has insufficient ventilation under heavy load, and the oil and gas in the box will escape into the atmosphere and pollute the environment; When the valve? If you drive straight, the oil consumption will be too high. ?
1. Check the vacuum degree of the valve. Unscrew the check valve on the engine, then connect the ventilation hose, run the engine at idle speed, and put your finger on the open end of the check valve. At this time, your fingers should feel the vacuum. If you raise your finger, there should be a "bang, bang" inhalation sound at the valve port. If your fingers don't feel vacuum or make noise, clean the check valve with cleaning solution? Check the ventilation hose again. What if it still doesn't work? Change.
2. Check the movement of the valve. Unscrew the check valve on the engine and insert it with a thin wooden rod. At this point, the plunger of the valve should be free to move back and forth. If the plunger of the valve does not move, it should be cleaned or replaced.