What are the symptoms of engine blow-by?
2 Answers
Engine power decreases, and engine oil deteriorates. The following is an introduction to engine blow-by: 1. Definition: Engine blow-by is a relatively comprehensive fault. Blow-by is one of the common faults during engine operation. It refers to the phenomenon where a portion of the high-temperature and high-pressure expanding gases generated during the combustion process escape from the engine through abnormal channels. Its occurrence and development seriously threaten the normal operation of the engine. In mild cases, it reduces output power and wastes energy, while in severe cases, it damages components and causes accidents. When blow-by occurs, the pressure and temperature at the end of compression, as well as the combustion pressure, decrease, leading to difficulties in engine starting, insufficient power, and increased fuel consumption. 2. Severe symptoms of blow-by: In severe cases, the engine may fail to start or operate. When blow-by noise is severe, it resembles knocking. Opening the oil filler cap may reveal a large amount of gas escaping. Common blow-by locations include blow-by from the valve cover and blow-by from the crankcase oil filler port, accompanied by white smoke.
I've been driving for over a decade and encountered engine blow-by issues. The main symptoms were noticeably reduced vehicle power – the acceleration felt sluggish when pressing the gas pedal, requiring much more effort than usual. What worried me more was the abnormally fast oil consumption. Every inspection showed significantly lower oil levels, and the oil had turned black and dirty, clearly contaminated. Another symptom was smoke coming from the PCV (crankcase ventilation system), appearing like small smoke pillars escaping through the engine hood gaps, which really concerned me. Additionally, fuel consumption increased by 1-2 liters per 100km, accompanied by slight knocking noises during engine operation and unstable idle. These issues not only affected driving experience but could also shorten engine lifespan. I realized I needed immediate professional inspection of cylinder sealing components to prevent major problems.
