Should I replace the valve seal when I remove the valve? Why does the valve seal age?

Many kinds of oil are used in cars, such as engine oil, brake oil, transmission oil, etc. In order to prevent these oils from leaking, there are special oil seals. Among them, valve oil seals are one kind, which are mainly used in the valve guide rod of the car. So when the valve needs to be removed, should the oil seal be replaced together?

Do I need to replace the valve seal when removing the valve?

It is best to replace the valve oil seal when disassembling the valve, because this part is very cheap and it doesn't cost much to replace a new one, but it plays a big role. If the valve oil seal leaks oil and burns oil to the same extent as the cylinder, and replacing the oil seal is very troublesome, it is safer to replace them together.

Moreover, the valve oil seal will be damaged during disassembly, resulting in poor sealing, and the engine oil will flow into the combustion chamber, causing oil burning, resulting in a second disassembly. Since this is the case, it is better to replace it directly at one time, saving worry, effort and money.

Why does the valve seal age?

The reasons for the aging of valve oil seal are as follows:

One reason is that the durability of the valve oil seal itself is poor, resulting in a short service life. For example, BMW engines may easily have valve oil seal aging and oil burning.

Another reason is that the vehicle has been used for too long, the oil seal will harden and then lose its elasticity, causing the engine oil to burn.

Another method is to use fake oil, which causes serious carbon deposits in the sludge in the engine. The carbon deposits in the sludge may cause the oil seal to lose its elasticity and may also cause the engine to burn oil.

If the valve oil seal is aging and leaking, it can be directly maintained and replaced without disassembly, so that the engine oil problem can be solved relatively easily.

Working principle of automobile oil seal

Oil seal is a mechanical component that seals grease. It is commonly used in various mechanical bearings. Its function is to isolate the parts that need to be lubricated from the outside world to prevent lubricating oil from leaking. It has the function of sealing oil inside and sealing dust outside. The current oil seal materials are mainly various rubbers. Such as: nitrile rubber, acrylic rubber, polyurethane rubber, silicone rubber, fluororubber, polytetrafluoroethylene rubber, etc. Oil seals have the advantages of simple structure, light weight, small installation location, and easy processing.

The sealing mechanism of the oil seal is that the sealing lip of the oil seal directly contacts the surface of the rotating shaft, forming a narrow ring with a width of 0.1~0.2mm, that is, the sealing interface. Under the action of pre-pressure (usually a spring), the average radial contact pressure between the oil seal and the shaft is about 1N/mm2. When the lubricating oil pressure is lower than the pressure value, the oil seal can prevent leakage.