Regarding the issue of oil sedimentation
author: Ann
2025-03-03
Why does engine oil have precipitation? Is it a quality problem? Or a design problem?
1. Precipitation is a normal phenomenon. The bottom of the precipitation is detergent (calcium salt). It is also the most added additive in lubricating oil. Because Shell is a manufacturer that sells cleaning and dispersion, the precipitation of Shell engine oil is more serious than other brands. If you pay attention to the elemental analysis report of the spectrum, the calcium content of Shell engine oil is generally higher than other brands (for European and American brands, because the route of Japanese oil is relatively special), so people often report the precipitation of Shell engine oil.
2. Calcium salt detergent has been developed for decades, and the process and raw materials have not changed. Whether it is low-base petroleum-grade calcium salt (mainly acts on the high-temperature skirt of the piston ring, the base value is very low, but the base value retention ability is very good), or high-base synthetic sulfonic acid calcium salt (TBN above 300, a small amount of oil can significantly increase the base value, but the base value also drops rapidly. The compound agent formula is a combination of low-base calcium salt and high-base calcium salt), the main ingredients are sulfonate and calcium hydroxide (lime). So if too much detergent is added, some of it will definitely precipitate. This has nothing to do with quality control and technology.
3. The number of certifications for engine oil is directly proportional to the amount of additives added. The base oil grade selected for engine oil is inversely proportional to the solubility of additives. In other words, the more certifications, the more additives. The more refined the base oil is, the worse the solubility of additives (the base oil is too clean and the density is too small). Therefore, it is more normal for high-grade Shell engine oil to precipitate frequently (in fact, low-grade Shell is also prone to precipitation because it takes the clean and dispersed route and has a high calcium formula)
4. People often complain that Shell engine oil performance decays quickly, and it ejaculates prematurely after about 5,000 kilometers. In fact, this is also caused by the clean and dispersed route. The viscosity index improvers used by Shell are all large molecular weight, and the large molecular weight has good thickening ability. In this way, the viscosity index improver added will be reduced. The viscosity index improver is a polymer, which is easy to decompose and form sludge under long-term high temperature, which no one can avoid. Therefore, in order to add less viscosity index improver, Shell can only choose a large molecular weight viscosity index improver with strong thickening ability. But the formula of engine oil itself is a balance. What is the downside of choosing a high molecular weight viscosity modifier? It is that the molecular weight is large and it is easy to be cut off, which means that the shear stability of Shell engine oil is relatively poor, and the viscosity drops early, so everyone reports that its performance is premature.
5.0W-40 and 5W-40 use viscosity modifiers to increase the viscosity. The larger the span, the more viscosity modifiers. That is to say, 0W-40 has more viscosity modifiers than 5W-40, and 5W-40 has more viscosity modifiers than 10W-40. So many car owners report that the engine using 40 oil generally has more sludge than 30 viscosity oil. This is the reason. No matter which viscosity modifier, it is a polymer and is most afraid of high temperature. The more you add, the greater the sludge pressure. Any engine oil will produce sludge, just the difference in amount. Japanese ultra-high viscosity index 20 engine oil is made with PMA viscosity modifier. PMA has the worst high temperature stability among the three viscosity modifiers (but it has the best viscosity index). So this is why Japanese high viscosity index 20 oils are required to be replaced within 5,000 (European and American long-lasting oils, 4S stores ask you to replace them for 5,000, which is a waste of money, but Japanese high viscosity index 20 oils are best made according to the manufacturer's requirements, and don't innovate on your own)
6. Digest the fourth point first, then look at this one. Shell's clean and dispersed route does not mean that it is "engine cleaning oil", don't over-interpret it at the Chinese level. Any engine oil will have sludge, and Shell's clean and dispersed route can only try to reduce the generation of sludge, and at most clean a small amount of sludge (the effect is better than nothing). It will not have a cleaning effect on carbon deposits and paint films caused by the use of external supplements (maintenance products) and fake oils. I remember that Total has engine cleaning oil, which is made of odorless kerosene, and it is the authentic engine cleaning oil. Don't have the illusion of "cleaning" for "clean and dispersed engine oil". And if it is a paint film, even a dedicated engine cleaning oil can't wash it off.
7. Lubricant competition continues to this day, and many manufacturers have their own design concepts for their products. American engine oil is long-lasting, Japanese engine oil is energy-saving, and Shell's understanding of engine oil is that "cleanliness and dispersion" must be good. No matter what route is taken, the balance of engine oil cannot be broken. In other words, if you want to take all three into account, it is impossible (even if technology advances for another 50 years).
1. Precipitation is a normal phenomenon. The bottom of the precipitation is detergent (calcium salt). It is also the most added additive in lubricating oil. Because Shell is a manufacturer that sells cleaning and dispersion, the precipitation of Shell engine oil is more serious than other brands. If you pay attention to the elemental analysis report of the spectrum, the calcium content of Shell engine oil is generally higher than other brands (for European and American brands, because the route of Japanese oil is relatively special), so people often report the precipitation of Shell engine oil.
2. Calcium salt detergent has been developed for decades, and the process and raw materials have not changed. Whether it is low-base petroleum-grade calcium salt (mainly acts on the high-temperature skirt of the piston ring, the base value is very low, but the base value retention ability is very good), or high-base synthetic sulfonic acid calcium salt (TBN above 300, a small amount of oil can significantly increase the base value, but the base value also drops rapidly. The compound agent formula is a combination of low-base calcium salt and high-base calcium salt), the main ingredients are sulfonate and calcium hydroxide (lime). So if too much detergent is added, some of it will definitely precipitate. This has nothing to do with quality control and technology.
3. The number of certifications for engine oil is directly proportional to the amount of additives added. The base oil grade selected for engine oil is inversely proportional to the solubility of additives. In other words, the more certifications, the more additives. The more refined the base oil is, the worse the solubility of additives (the base oil is too clean and the density is too small). Therefore, it is more normal for high-grade Shell engine oil to precipitate frequently (in fact, low-grade Shell is also prone to precipitation because it takes the clean and dispersed route and has a high calcium formula)
4. People often complain that Shell engine oil performance decays quickly, and it ejaculates prematurely after about 5,000 kilometers. In fact, this is also caused by the clean and dispersed route. The viscosity index improvers used by Shell are all large molecular weight, and the large molecular weight has good thickening ability. In this way, the viscosity index improver added will be reduced. The viscosity index improver is a polymer, which is easy to decompose and form sludge under long-term high temperature, which no one can avoid. Therefore, in order to add less viscosity index improver, Shell can only choose a large molecular weight viscosity index improver with strong thickening ability. But the formula of engine oil itself is a balance. What is the downside of choosing a high molecular weight viscosity modifier? It is that the molecular weight is large and it is easy to be cut off, which means that the shear stability of Shell engine oil is relatively poor, and the viscosity drops early, so everyone reports that its performance is premature.
5.0W-40 and 5W-40 use viscosity modifiers to increase the viscosity. The larger the span, the more viscosity modifiers. That is to say, 0W-40 has more viscosity modifiers than 5W-40, and 5W-40 has more viscosity modifiers than 10W-40. So many car owners report that the engine using 40 oil generally has more sludge than 30 viscosity oil. This is the reason. No matter which viscosity modifier, it is a polymer and is most afraid of high temperature. The more you add, the greater the sludge pressure. Any engine oil will produce sludge, just the difference in amount. Japanese ultra-high viscosity index 20 engine oil is made with PMA viscosity modifier. PMA has the worst high temperature stability among the three viscosity modifiers (but it has the best viscosity index). So this is why Japanese high viscosity index 20 oils are required to be replaced within 5,000 (European and American long-lasting oils, 4S stores ask you to replace them for 5,000, which is a waste of money, but Japanese high viscosity index 20 oils are best made according to the manufacturer's requirements, and don't innovate on your own)
6. Digest the fourth point first, then look at this one. Shell's clean and dispersed route does not mean that it is "engine cleaning oil", don't over-interpret it at the Chinese level. Any engine oil will have sludge, and Shell's clean and dispersed route can only try to reduce the generation of sludge, and at most clean a small amount of sludge (the effect is better than nothing). It will not have a cleaning effect on carbon deposits and paint films caused by the use of external supplements (maintenance products) and fake oils. I remember that Total has engine cleaning oil, which is made of odorless kerosene, and it is the authentic engine cleaning oil. Don't have the illusion of "cleaning" for "clean and dispersed engine oil". And if it is a paint film, even a dedicated engine cleaning oil can't wash it off.
7. Lubricant competition continues to this day, and many manufacturers have their own design concepts for their products. American engine oil is long-lasting, Japanese engine oil is energy-saving, and Shell's understanding of engine oil is that "cleanliness and dispersion" must be good. No matter what route is taken, the balance of engine oil cannot be broken. In other words, if you want to take all three into account, it is impossible (even if technology advances for another 50 years).
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