Detailed explanation of engine oil function and replacement method

Oil is the blood of the engine and oil maintenance is known as minor maintenance and is the most basic item. Why should I change the oil? What should I pay attention to when using oil? The simplest oil maintenance chapter is here!

How does engine oil work

The oil passes through the cylinder head and cylinder body and flows directly into the oil pan along the oil passage. The oil pan is equivalent to a safe and plays a role in storing the oil.

When the engine is working, the driving gear on the camshaft drives the transmission gear of the oil pump, which causes the driving gear fixed on the driving gear shaft to rotate, thereby driving the driven gear to rotate in the opposite direction, and spread the oil from the oil cavity to the backlash of the pump.

Sealing: During the operation of the engine, the oil will penetrate into the gap between the piston and the gas 51 to form a sealing ring to seal the gas in the cylinder and effectively prevent the gas from the gas button to maintain the cylinder pressure.

Lubrication: There is rapid relative sliding between the piston and the steam button, and between the main shaft and the bearing bush. To prevent excessive wear of the parts, it is necessary to establish an oil film between the two sliding surfaces to separate the surfaces of the relatively sliding parts. Make the machine work without friction, reduce wear and run smoothly.

Cooling: The engine generates a high temperature of 400-600 degrees Celsius when it is running. When the oil reaches the operating part, it will absorb heat, and then take the heat away to help the parts dissipate heat.

Cleaning: Engine oil can clean the engine, remove the impurities remaining in the filter, protect the metal surface from the acid corrosion oil formed in the combustion process, and also take away the combustion residues (carbon deposits) and the combustion products of the lubricating oil or oxidation products. 

Anti-rust: Due to the water resistance of the engine oil, the engine oil can form an oil film in the metal parts to isolate the moisture in the air and prevent rust and corrosion.

Shock absorption: The oil can withstand a certain impact load from the bearing transmission, to a certain extent, eliminate the impact load between the bearing and other parts of the engine, and play a buffering role. 

Misunderstanding of the use of oil

Common misunderstanding 1: Change the oil when it turns black

Engine oil has a cleaning effect. It can clean the carbon deposits and oxides inside the engine and dissolve them. The black substances in the engine oil we see are the carbon deposits and oxidation products inside the engine. Therefore, no matter how clear the engine oil is, as long as it is added to the engine to work for a period of time, it will turn black. This is because the oil is playing its cleaning role. Therefore, it is completely normal for the oil to turn black.

Common Misunderstanding 2: The thinner the oil, the better

The viscosity of high-end engine oils is relatively low, and many users will think that the lower the viscosity, the better the engine oil. In fact, the choice of oil viscosity still has to refer to the manual, and only suitable can achieve the best use effect. Of course, you also need to refer to the actual working conditions of the engine. Too low or too high viscosity will lead to poor lubrication of the vehicle or excessive running resistance respectively.

Common Misunderstanding 3: Only add oil but not change

The engine oil itself has clean performance. During the use of the engine oil, due to pollution, oxidation and other reasons, the performance will gradually decline and at the same time it will be consumed. If only the oil is added and not replaced, it can only make up for the lack of quantity, but cannot completely compensate for the loss of performance.

Common misunderstanding 4: Change additives privately

High-quality engine oil is a finished product with a variety of engine protection functions. The formula already contains a variety of additives, including anti-wear agents, and the engine oil pays attention to the balance of the formula to ensure the full play of various performances. Adding other additives on your own will not bring additional protection to the equipment, but will easily react with the chemicals in the oil, resulting in a decline in the overall performance of the oil.

Common Misunderstanding 5: It is better to add more oil than less

The amount of oil should be controlled between the high and low marks of the oil dipstick. If there is too much oil, the oil will escape from the gap between the cylinder and the piston into the combustion chamber and burn to form carbon deposits. These coke deposits will increase the compression ratio of the engine and increase the probability of knocking. Secondly, too much oil increases the stirring resistance of the crankshaft connecting rod and increases fuel consumption. Furthermore, adding more oil will increase the internal pressure of the engine, which will easily lead to oil leakage of the engine seals.

How to use engine oil correctly

Regularly check the oil level

The equipment must be placed horizontally when checking the oil level

Reminder: To ensure the accuracy of the measured value, wait at least 15 minutes after the engine has been stopped before starting to check the oil level. This period of time can allow the oil to flow back to the oil pan.

The amount of oil needs to be controlled between the high and low marks of the oil dipstick

Reminder: Too much oil above the "high level scale line" increases the stirring resistance of the crankshaft connecting rod and increases fuel consumption; engine oil below the "low level scale line" will cause insufficient lubrication, cleaning, and cooling capabilities, and increased wear , In severe cases, it will cause major failures such as engine bearing score and crankshaft lockup).

Change the oil regularly

The choice of oil

Since the engine oil has a great influence on the performance and life of the engine, the engine oil of the same series, use grade, and viscosity grade should be selected strictly in accordance with the provisions of the instruction manual. If there is no manual, use the following method to select a suitable engine oil specification.

▲ Choose the corresponding series of engine oil according to the fuel used by the engine. According to the classification of API (American Petroleum Institute), diesel engine chooses C series oil (the diesel engine oil specification has developed from the initial CA to CI-4 and many other specifications).

▲Select according to SAE (Society of Automotive Engineers) standard viscosity value

Oil replacement cycle

The oil does not need to be changed when it turns black, but to follow the oil replacement standard.

Oil replacement method and steps

Run the engine until the water temperature reaches 60°C and stop the engine.

Remove the oil drain plug and drain the oil immediately to ensure that all oil and suspended dirt in the engine are removed.

 

Fill the engine with clean oil to the proper oil level.

Note: The oil pressure of the engine must be displayed on the instrument within 15 minutes after the engine is started. If the oil pressure is not displayed within 15 seconds, immediately stop the engine to avoid damage. Confirm whether the oil level in the oil pan is correct.