Misunderstanding of the hottest lubricating grease

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Misunderstandings of lubricating grease in bearing repair and use

20 misunderstandings of lubricating grease in bearing repair and use:

1. apply grease when installing cylinder gasket

some repairmen like to apply a layer of grease on the cylinder gasket when installing cylinder gasket, thinking that this can increase the tightness of the engine. As everyone knows, this is not only useless, but harmful. As we all know, cylinder gasket is an important sealing material between the cylinder block and cylinder head of automobile engine. It not only requires strict sealing of high-temperature and high-pressure gas generated in the cylinder, but also must seal the cooling water and oil with a certain pressure and flow rate penetrating the cylinder head and cylinder body. Therefore, it is required to pay special attention to its sealing quality when disassembling the cylinder gasket

if you apply grease on the cylinder gasket, when the cylinder head bolts are tightened, part of the butter will be squeezed into the cylinder water channel and oil channel. When the cylinder is working, due to the high temperature, part of the butter left between the cylinder gaskets will flow into the cylinder for combustion, and the other part will burn into carbon deposits on the joint surface of the cylinder block and the cylinder head. Under the action of high pressure and high temperature, it is very easy to puncture or burn through the cylinder gasket, causing engine air leakage. Therefore, do not apply grease when installing the cylinder gasket

2. diesel vehicles use gasoline engine oil

engine oil can be divided into gasoline engine oil and diesel engine oil. Although gasoline engines and diesel engines work under the same conditions of high temperature, high pressure, high speed and high load, there are still great differences between them. The compression ratio of diesel engine is more than twice that of gasoline engine, and the impact of high temperature and high pressure on its main parts is much greater than that of gasoline engine, so the manufacturing materials of some parts are different. For example, the main bearing bush and connecting rod bearing bush of gasoline engine can be made of Babbitt alloy with soft material and good corrosion resistance, while the bearing bush of diesel engine must be made of high-performance materials such as lead bronze or lead alloy, but these materials have poor corrosion resistance. Therefore, in the refining process of diesel engine oil, more anti-corrosion agents should be added, so that a protective film can be formed on the surface of the bearing bush during use to reduce the corrosion of the bearing bush and improve its wear resistance. Because gasoline engine oil does not have this kind of anti-corrosion agent, if it is added to the diesel engine, the bearing bush will be prone to spots, pits, and even flakes in use. The engine oil will soon become dirty, and lead to Bush burning and axle holding accidents. In addition, the sulfur content of diesel oil is higher than that of gasoline. This harmful substance will form sulfuric acid or sulfite during combustion, which will rush into the oil pan together with high-temperature and high-pressure exhaust gas, accelerating the oxidation and deterioration of engine oil. Therefore, some antioxidant additives need to be added in the refining process of diesel engine oil to make the engine oil alkaline. If there is acid gas channeling in, it can play a certain role in neutralization and will not cause the engine oil to oxidize and deteriorate too quickly. Gasoline engine oil does not add this additive, because it is neutral. If it is used in diesel engine, it will deteriorate and fail quickly due to the corrosion of the above acid gases. Therefore, never fill the diesel engine with gasoline engine oil

3. domestic cars blindly use imported engine oil

some car owners think that imported engine oil must be better than domestic engine oil, so they use imported engine oil on domestic cars, especially new cars. As everyone knows, the gains often outweigh the losses, and there will be many disadvantages. For example, most imported engine oils have low viscosity, which cannot meet the requirements of domestic vehicles for engine oil viscosity. In addition, the material thermal expansion coefficient and fitting clearance of various mating parts of domestic engines are larger than those of imported vehicles, and most domestic vehicle engines are not equipped with oil radiators. If imported oil is blindly used, the oil pressure will be low because the engine oil is too thin at normal operating temperature, and even cannot reach the specified working pressure, which cannot meet the needs of normal lubrication, and the wear of the engine will be aggravated

4. Do not fill oil when assembling the oil pump

when installing the repaired oil pump on the vehicle, if you do not fill oil into the gear chamber of the oil pump, the oil pump will not pump oil, causing accidents such as Bush burning. Because the gear oil pump generates suction by relying on the small fit clearance between the gear and the inner wall of the housing, as well as the correct fit clearance between the gears. If oil is not filled into the gear chamber when the oil pump is installed or cleaned, the oil pump cannot generate sufficient suction. For the gear oil pump with certain wear, the above phenomenon is more obvious. Therefore, don't forget to fill the gear chamber with oil when installing the oil pump

5. engine oil blackening is the deterioration of engine oil

engine oil works under harsh high temperature conditions, which is easy to oxidize and deteriorate, produce acidic substances and synthesize polymer deposits, so as to destroy lubrication. In addition, the combustion exhaust gas channeling into the crankcase will also promote the oxidation and deterioration of engine oil. Therefore, after a certain period of use, the engine oil will usually blacken and deteriorate, losing its proper lubrication. However, with the continuous improvement of the quality of lubricating oil, especially the popularization and use of thickened engine oil, the blackening of engine oil does not necessarily mean the deterioration of engine oil. This is because the clean dispersant added to the thickened engine oil disperses the deposits on the parts into the oil, making the engine oil black. Whether it has deteriorated should be tested for various indicators, and the oil should be changed regularly according to the quality to reduce unnecessary waste. For example, engine oil added with engine protectants such as yyl02 will also blacken after a certain period of use. Therefore, the blackening of engine oil does not mean the deterioration of engine oil

6. choose lubricating oil blindly

lubricating oil plays the role of lubrication, cooling, cleaning and sealing. The quality of lubricating oil is directly related to the service life of the engine, so don't blindly choose engine oil. New vehicles have very strict requirements for lubricating oil. The choice of lubricating oil, when to replace it, and how to replace it should be carried out in accordance with the manufacturer's regulations

when selecting engine oil, attention should be paid to both quality grade and viscosity grade. First, the selection of service performance level should be carried out according to the compression ratio, displacement, etc; Then select the viscosity level according to the temperature and load. The quality of engine oil should be better than low. Good quality engine oil can ensure good engine lubrication, reduce wear, prolong engine service life, extend oil change cycle, and reduce the frequency and difficulty of maintenance and repair. When selecting the viscosity of engine oil, in addition to temperature conditions, low viscosity engine oil should be selected as far as possible under the condition of ensuring engine lubrication and sealing, so as to save fuel

7. it is best to use multi viscosity lubricating oil

multi viscosity lubricating oil (also known as multi-grade lubricating oil) has the property of light oil at low temperature and heavy oil at high temperature. When multi-grade oil is recommended, a multi-grade oil can replace a variety of single-grade oils. Although multi-level oil can meet the requirements of extremely cold and warm seasons and heavy-duty engine oil, especially those diesel engine oils that have no difficulty in starting in cold weather, it is usually recommended to use lubricating oil with single viscosity, which is conducive to the lubrication of the engine and prolongs the service life of the engine. Therefore, do not think it is best to use multi viscosity lubricating oil

8. mix engine lubricating oil

all kinds of lubricating oil, except for the viscosity grade, the base oil is the same, and the difference only lies in the variety and quantity of its added components. Therefore, the variety and quality grade of lubricating oil are generally divided according to the variety and quantity of added components. Lubricants with different types of additives cannot be mixed, otherwise the additives in the oil may react chemically and damage the due effect of the lubricant. With the continuous improvement of additives and their formulas, some general-purpose oils have been developed and produced. For example, QE/cc, QF/CD and other lubricants for gasoline and diesel engines. They can be used in general within the indicated level range. Therefore, whether the lubricating oil can be mixed or not, we should comprehensively compare the name, variety and brand of the oil according to the requirements of the manual, and reasonably select the use level and appropriate brand. We should not blindly use it according to the economic insurance, let alone mix it

9. the lubricating oil is only added without replacement

many car owners only pay attention to checking the oil quantity of the lubricating oil and adding it according to the standard, but do not pay attention to checking the quality of the lubricating oil, ignoring the brittle replacement of the deteriorated engine oil, although the ceramics and graphene are brittle, which leads to some moving parts of the engine always operating in a poor lubrication environment, thus accelerating the wear of the lubricating parts. Therefore, generally speaking, the lubricating oil of the engine should be changed when the vehicle travels 3500 ~ 5000km

10. it is better to fill more lubricating oil than less

the harm of too little engine lubricating oil is well known. Therefore, some car owners are afraid of burning tiles due to lack of oil, and think that adding more lubricating oil is better than adding less. Therefore, they often do not add oil according to the regulations, so that the lubricating oil exceeds the standard. In fact, too much lubricating oil has many hazards:

⑴ when the car is driving, the crankshaft stirs, which will deteriorate the oil foam and increase the crankshaft rotation resistance. Therefore, it will not only increase the engine fuel consumption, but also reduce the engine power

⑵ oil consumption increases due to the increased combustion of oil from the cylinder wall to the combustion chamber

⑶ accelerates the formation of carbon deposition in the combustion chamber, making the engine prone to deflagration

therefore, it is a misunderstanding to prefer more engine oil to less. Generally, the oil level should be kept slightly lower than the scale on the dipstick, and too high oil level will be counterproductive

11. The higher the viscosity of the lubricating oil, the better.

in order to prevent the indirect contact surface wear of moving parts, the lubricating oil must have sufficient viscosity so that an oil film can be formed between moving parts at various operating temperatures. However, the viscosity of the lubricating oil shall not be higher than the degree that affects the start of the engine, and the minimum friction is required under continuous operation. The use of lubricating oil with too high viscosity will increase the wear of machine parts, because:

⑴ the viscosity of engine lubricating oil is too high, the flow is slow, the upward flow is slow, and the oil pressure is high, but the passing amount of lubricating oil is not much, so it cannot be added to the friction surface in time

⑵ due to the high viscosity of the lubricating oil, the friction between the friction surfaces of the parts increases. In order to overcome the increased friction, it is necessary to consume more fuel and reduce the output power of the engine

⑶ if the viscosity of lubricating oil is large, the circulation speed of oil will be slow, and its cooling and heat dissipation effect will be poor, which is easy to overheat the engine

⑷ due to the slow circulation speed of lubricating oil, the number of times of passing through the lubricating oil filter is less, so it is difficult to clean the worn metal debris, carbon particles and dust from the friction surface in time

therefore, do not use engine lubricating oil with too high viscosity, and the higher the viscosity, the better. Under the condition of ensuring lubrication, choose lubricating oil with low viscosity as far as possible according to the temperature range when using. However, for engines with serious wear and large clearance, lubricants with slightly higher viscosity can be appropriately selected

12. Fill the universal joint spider with grease

it is clearly stipulated in the general automobile maintenance manual that the key teeth and intermediate bearings of the transmission shaft telescopic sleeve use calcium base grease, and the needle roller bearings of the spider and the intermediate bearings of the rear axle transmission shaft of three axle drive vehicles use gear oil. However, in practical work, due to the lack of filling equipment, some repairmen mistakenly lubricated the cross shaft needle roller bearings with calcium base grease for convenience, causing a large number of cross bearings to be prematurely damaged. Because the universal joint spider gear oil filling nozzle is a very ordinary grease fitting, it often gives people a misunderstanding. In fact, butter is added

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