Many car owners change engine oil，Only choose expensive high-grade engine oil，It seems that the higher the number and the more expensive the engine oil, the better。Many car owners mistakenly added high-grade engine oil，Thus leading to an increase in carbon deposits。To this，Experts say，The current price of G-grade engine oil with lower grades on the market is basically around 80 yuan to 90 yuan，The price of SL grade engine oil with a higher grade is around 130 yuan to 140 yuan。

Some car enthusiasts do not understand the characteristics of the car，I think the higher the mark on the car, the better the expensive engine oil will be。Always choose higher grade engine oil，Not necessarily enhanced engine protection。Especially for some older and backward engines，High-grade engine oil will also increase engine oil consumption，Generating carbon deposits。

Motor oil is not just for anti-wear

Motor oil is as important to the engine as blood is to the heart。The engine is the heart of the car，There are many metal surfaces in the engine that rub against each other，These parts move fast、Poor environment，Operating temperature can reach 400℃ to 600℃。Under such harsh working conditions，Only qualified lubricants can reduce the wear of engine parts，Extended service life。

Between piston and cylinder，There is rapid relative seabet iosliding between the main shaft and the bearing，To prevent parts from wearing out too quickly，An oil film needs to be established between the two sliding surfaces。There is an oil film of sufficient thickness to separate the surfaces of relatively sliding parts，Thus achieving the purpose of reducing wear。Motor oil can also bring heat back to the oil tank and then dissipate it into the air to help the water tank cool the engine。Good engine oil can remove carbide from engine parts、Oil sludge、Wear metal particles are brought back to the oil tank through circulation，Flow through lubricating oil，Dirt generated on the working surface of flushing parts。Oil can form a seal between the piston ring and the piston，Reduce gas leakage and prevent external pollutants from entering。

Lubricating oil can absorb water on the surface of parts to prevent water、Air、Contact between acidic substances and harmful gases and parts。When the engine cylinder port pressure rises sharply，Sudden intensification of piston、Piston chips、Loads on connecting rods and crankshaft bearings，This load passes through the transmission lubrication of the bearing，To buffer the impact load。

The right one is the best

The engine oil currently on the market can be simply divided into two types: mineral oil and synthetic oil due to their different base oils。

Synthetic oil is divided into: fully synthetic and semi-synthetic。Fully synthetic motor oil is the highest grade。The biggest difference between the two is that synthetic oil can be used at a wider range of temperatures，Longer lifespan，And cost more；Same oil film requirements，Synthetic oil can be achieved with lower viscosity，Mineral oil requires a thicker viscosity relative to synthetic oil to achieve this requirement。In the same working environment，Synthetic oil has a much longer service life than mineral oil，Therefore the cost is higher，But Seabetafter comparing the number of oil changes，Not much higher than mineral oil。

Different grades of engine oil have different characteristics，Its low-temperature startup and high-temperature anti-wear、Adhesion also has different manifestations。The viscosity of engine oil is inversely proportional to temperature，When the engine is cold，Higher oil viscosity，If the selected engine oil is thicker，will give the starter motor、Battery, etc. add additional losses；But if the engine oil is too thin，Under high temperature operation, it is difficult to form a sufficient protective film and cause insufficient lubrication，Resulting in increased wear of machine parts。

The viscosity of lubricating oil is often marked with SAE and other grades。Example: SAE15W-40、SAE5W-40，"W"means winter，The smaller the number in front of it, the better the low-temperature fluidity of the engine oil，Represents the lower the ambient temperature available，The better the engine protection during cold starts；"W"The number behind (behind the horizontal line) is an indicator of the high temperature resistance of the engine oil，The larger the value, the better the protective performance of the engine oil at high temperatures。

You ask and I answer

Q: What problems will occur if the wrong amount of oil is added?

Answer: The normal height of the engine oil level is between the upper and lower marks on the oil dipstick，Adding too much oil will cause too much oil to enter the combustion chamber through splashing，Resulting in carbon deposition，And lead to an increase in the operating resistance of various parts in the crankcase，So be sure to adjust it to normal levels。

Q: Is it okay to just change the engine oil without changing the filter?

Answer: Engine oil not only lubricates，It also plays a very important role in taking away the dirt inside the engine，These dirty things are filtered out by the machine seabet myfilter，If you change the oil, do not change the filter，Dirty things cannot be completely removed，So there is no point in changing the oil。When changing oil, you must change the filter，This is a dead rule。