Oil leakage from the engine of Aika garage may help.

　　[Original by Aika Car Center]

　　Engine oil leakage is as hard to prevent as a person catching a cold, and it will inevitably appear after a certain mileage. Although the tiny leakage will not affect the normal driving, the dust entering the engine room will stick to the surface of the oil, forming greasy dirt over time, which will seriously hinder the heat dissipation of the engine.

　　Let’s not talk about what harm oil leakage will bring to the engine for the time being. It is enough to make people hate it. Take the "patient" who checked into the garage this time. Although this is a short-lived Excelle, judging from the oil leakage of the engine, you will not imagine that this is a quasi-new car with a mileage of less than 40000km.

First, how to judge oil leakage

　　Slight oil leakageYou can take no measures for the time being, butTo attract enough attention,Because the oil leakage point is the weakest part of the engine seal, the leakage will become more and more serious as time goes by.

　　When the vehicle is running, the wind flowing into the engine room will blow the leaked engine oil to all corners. This is the reason why oil sludge will stick to the parts without oil leakage.

　　During inspection, the leakage can be identified according to the wetting degree of the mimeograph.The wettest part of the mimeograph is the place where the oil leakage is the most serious.After external rough inspection, it can be locked that the oil leakage point is mainly concentrated in the valve cover, and the oil leakage is caused by the aging of the gasket.

Second, the best way to treat leakage — — Change!

　　The function of the gasket is to prevent oil from leaking from the engine.Once leakage occurs, replacing the gasket is the only way out.

　　In fact, the replacement of the valve cover gasket is not complicated. Just remove a few screws to remove the valve cover, and then replace it with a new gasket. Without saying much, we will go directly to the link of replacing the valve cover gasket.

　　The engine room structure of this Buick Excelle is relatively simple, so this repair is not difficult. Although the maintenance method cannot cover all models, you can probably understand the structure of the valve cover and gasket through the disassembly and assembly of this engine, and finally choose whether to replace it yourself according to the actual situation.

1. Pay attention to check whether there are other oil leakage points during disassembly.

　　The fixing screws of the valve cover cannot be seen from the outside. You need to remove the dust cover of the engine first, and then remove the dust cover screw.

　　The leaked engine oil will affect the life and friction of the belt, so we can also replace the camshaft oil seal after we remove the valve cover. Fortunately, the back of the gear is very clean, and it can basically be concluded that the camshaft oil seal is intact.

　　The maintenance of the timing mechanism is very important for the engine.The operation of engine is closely related to the correct valve timing. Timing misalignment may cause the engine to fail to start;When the timing belt breaks, it is likely to cause the valve to bend; If it breaks during driving, the top of the piston may be punctured.

　　(Now that we’re here, let’s take a short break. Let’s briefly talk about the principle of crankcase ventilation.)

　　The high temperature of the engine will make the engine oil in the crankcase generate steam, and at the same time, some exhaust gas after gasoline combustion will also jump into the crankcase, resulting in excessive pressure in the engine. When the pressure is too high, the circulation of engine oil will be hindered, which will affect the lubrication of components, and at the same time, high pressure will increase the possibility of oil leakage at the sealing parts.

　　So,It has become a necessary subject to discharge oil vapor in time.

　　At present, all engines adopt crankcase forced ventilation. Different from natural ventilation, forced ventilation will make the steam in the crankcase return to the intake port and the combustion chamber for secondary combustion, thus avoiding air pollution and improving the economy and reliability of the engine.

　　This is mainlyIn order to keep the pressure in the crankcase consistent under different working conditions.And designed.

　　What if the ventilation pipe is only arranged in front or behind the throttle valve?

　　At low speed and small load, the crankcase gas may not be pumped out; However, if it is arranged behind the throttle, it may form excessive vacuum under low speed and small load, which may lead to the generation of burning oil.

　　In fact, the oil entering the spark plug hole will not have much influence on the ignition system. Unlike water, oil has certain insulation, and the ignition coil is not subject to leakage.