What are the effects of a faulty one-way valve in the valve cover?
2 Answers
If the one-way valve in the valve cover (also known as the crankcase breather valve) fails, it can affect the ignition and performance of the air-fuel mixture, thereby impacting the engine's power output. This is particularly noticeable during engine idle, low-speed operation, light loads, and when the engine is cold. The following are potential causes of engine surging: 1. High engine idle speed. 2. Improper adjustment of the throttle cable or throttle position sensor, leading to excessively high main oil pressure. 3. Delayed gear shifting. 4. Cracked or loose vacuum hose of the vacuum-type throttle valve. 5. Faulty main oil pressure regulator, causing excessively high main oil pressure. 6. Stuck damper piston, preventing proper damping. 7. Missing one-way valve steel ball, resulting in rapid engagement of shift actuators (clutch or brake). 8. Slipping shift actuators. 9. Non-functioning oil pressure solenoid valve. 10. Faulty engine control unit (ECU).
I had a problem with the one-way valve in my old car before, and it was really a nightmare. Every time I started the engine cold, blue smoke would come out of the exhaust pipe, and the oil consumption was extremely high—I had to top up half a liter every 1,000 kilometers. The engine would shake like it was dancing at idle, and the check engine light on the dashboard would flicker occasionally. The most annoying part was the abnormal crankcase pressure, which caused oil to seep out from the oil pan seal. If left unrepaired, the catalytic converter would likely be ruined, and the emissions test would definitely fail. This one-way valve may seem small, but it plays a crucial role—it controls the crankcase ventilation system and maintains the internal pressure balance of the engine. I recommend replacing it as soon as you notice the issue. You can buy an OEM part online for just a few dozen bucks.
