Reasons for Excessive Negative Pressure in the Crankcase
2 Answers
Crankcase negative pressure becomes excessive due to inadequate ventilation. More information about the crankcase is as follows: 1. Crankcase ventilation methods: natural ventilation and forced ventilation. To prevent excessive crankcase pressure, extend the service life of engine oil, reduce component wear and corrosion, and prevent engine oil leakage, crankcase ventilation must be implemented. 2. Modern gasoline engines often use forced crankcase ventilation, also known as the PCV system. The purposes of crankcase ventilation are as follows: 1. To prevent lubricating oil from deteriorating and fuel from diluting the oil, thereby reducing wear and corrosion of engine components. 2. To reduce pressure and temperature and prevent leakage: gases entering the crankcase increase the pressure and temperature inside, causing lubricating oil to leak from the crankshaft oil seal and gaskets. 3. To recover combustible gases and reduce pollution. By re-introducing gases that have entered the crankcase back into the cylinders for combustion, CH compounds are recycled, while also reducing atmospheric pollution.
I've driven many cars and encountered situations with excessive crankcase vacuum. That time, my old car had the engine light come on accompanied by strange noises on the highway. After inspection, it was found that the PCV valve was completely clogged, causing poor ventilation; worn piston rings can also allow combustion gases to enter the crankcase, increasing the vacuum; additionally, air leaks in the pipes or overfilling the engine oil can also cause it. Excessive vacuum can cause engine oil to be sucked into the intake system, making the engine consume oil faster or even leak oil. If left unrepaired for a long time, the engine may be damaged. I think it's necessary to regularly check the ventilation system, especially for owners of old cars or those who frequently drive on highways; when symptoms appear, seek a repair shop as soon as possible to avoid greater losses.
