When the automobile lubrication system is working normally, the oil is constantly circulating in the engine, forcing the lubrication of each moving friction surface, and taking away the friction chip and friction heat from the friction surface, due to the effective splash to the cylinder wall, the sealing and lubrication of the piston ring and the cylinder wall under high temperature and high pressure are guaranteed.
The cause of oil deterioration
The centrifugal oil filter and the full-flow paper oil filter installed in the general automobile engine better maintain the good quality of the oil, but with the increase of the vehicle mileage, the filtration capacity of the engine oil filter gradually decreases, and the fuel, water, combustion products (such as carbon deposits, coke), oxidizing products of lubricating oil (colloids, asphalt, various acids, etc.), sand particles, dust, black and non-ferrous metal wear particles accumulated in the lubricating oil are becoming more and more numerous.
The colloid deposited in the combustion chamber and the top of the piston can form carbon deposits and cause abnormal combustion of the engine; There is glue on the piston ring and valve stem, which will make these parts bite and stick, aggravating the wear of various engine components.
The main reasons for the deterioration of engine oil are as follows:
Chip deposition caused by friction of the machine parts;
When burning, high temperature oxidation produces paint film, sediment colloid and carbon deposits;
Dust from the outside world invading the oil;
Acidic substances generated when burned;
Crankcase ventilation device is blocked, the oil heat dissipation is poor, and the oil is heated to naturally form a gelatinous substance;
Unbaligned gasoline mixed with mannequine oil in the over-concentrated mixture and cooling water in the water jacket seeps into the man's oil
Damage to the cylinder gasket or other causes cause water ingress into the cylinder block or crankcase. When the water content exceeds 0.1%, the added antioxidants, clean dispersants, etc. of the oil will fail, thus accelerating the oxidation process of the oil. When the oil contains more water, the oil lubricity becomes poor, the viscosity decreases, the oil film has a poor anti-friction effect, which leads to premature deterioration of the oil and rust of the parts, and causes serious mechanical accidents such as engine shaft holding and burning tiles.
The combustion chamber is not tightly sealed
Because the piston ring or cylinder is not found after wear, the fuel is long-term channeled into the crankcase and the oil is in contact, and the long-term high temperature causes the oil to deteriorate, the viscosity decreases, and the effect of the oil film is poor. In this way, the lubrication and sealing effect of the oil film on the piston ring and the cylinder wall gradually fails, and the friction between the piston ring and the cylinder wall continues to increase, so for a long time, whenever the piston is worked once, the number of high-temperature flames entering the crankcase increases, and the vicious circle continues, which eventually leads to the failure of oil lubrication in the crankcase, which eventually leads to problems such as burning tiles.
Do not change the oil for a long time
I don't know if you have such an exclamation. New cars landed, love the car as fate, worry about the car's various protection is not good and problems, maintenance on time or even in advance, oil choose the best brand. With the passage of time, the owner gradually becomes lazy, the enthusiasm for changing the oil every 5000 kilometers has become 7500 kilometers, and finally the owners who do not change the oil in 15000 kilometers are large.
Judgment of oil spoilage
First, through the observation of the color of the oil
Illumination method
On a clear day, use a screwdriver to lift the lubricating oil at a 45-degree angle to the horizontal plane. Compared with the sunlight, observe the oil droplet situation, under the light, you can clearly see that no abrasive chips in the lubricating oil is good, can continue to act, if the friction is too much, the lubricating oil should be replaced.
The high-quality oil is translucent yellow-brown, the oil is brown with water, and when the engine is running for a period of time, the oil is milky white and accompanied by foam. The black color of the oil is usually too much sludge and iron filings, or too many carbon particles in the oil. Pull out the oil ruler to observe whether the tick line is clear at the bright place, when the oil on the dipstick is not asked to be engraved, it means that the oil is too dirty and needs to be replaced immediately.
Of course, using the eyes to see if the oil has deteriorated requires empirical precipitation to exert its effect. So is there a testing magic weapon that is cheap and effective? Yes! Oil slow qualitative test strip.
The price of slow qualitative test strips is between 9-11 yuan (100 sheets a box) Each oil inspection requires a test strip, that is, the material cost of each inspection is about 1 cent. Slow qualitative test is used for the determination of ions and chemical components, it can determine whether the sample contains a certain amount of a certain substance, in which the test strip on the oil to detect the different components of the oil can determine the condition of the different components contained in the oil, so as to determine whether the oil has aged.
Method of testing:
Remove the oil dipstick, drop a drop of oil on the oil dipstick on the slow qualitative dipstick, place the dipstick horizontally, and wait for 24 hours. It was found that after 24 hours of standing test strips, three important ring-shaped areas mentioned below will appear.
1. Sedimentary ring: In the center of the spot is the place where the coarse particle impurity deposits in the oil are concentrated, and the degree of oil pollution can be roughly judged by the depth of the color of the sedimentary ring.
2, diffusion ring: the ring belt on the periphery of the deposition ring is called the diffusion ring, which is the trace left by the outward diffusion of fine particles of impurities suspended in the oil. The finer the particles, the farther they spread. The width and narrowness of the diffusion ring and the uniformity of the color are important factors, which indicate the dispersion ability of the additive in the oil to contaminate impurities.
3. Oil ring: In the outer oil ring of the diffusion ring, the color is from light yellow to brownish red, indicating the degree of oxidation of the oil.
The color of the oil diffused from the test strip determines the four grades of oil quality:
First level: there is no obvious boundary between the deposition area and the diffusion area of the oil spot, the color of the entire oil spot is uniform, the oil ring is light and bright, and the oil quality is good.
Secondary: the sediment ring is dark, the diffusion ring is wide, there is a clear dividing line, the oil ring is yellow at different depths, the oil quality has been contaminated, and the oil can still be used.
Tertiary: the sediment ring is dark black, the sediment is dense, the diffusion ring is narrow, the color of the oil ring is darker, and the oil quality has deteriorated.
Four levels: only the central sedimentary ring and the oil ring, there is no diffusion ring, the sediment ring black sediment is dense and thick, not easy to dry, the oil ring is dark yellow and light brown, and the oil has been oxidized and deteriorated.
Second, observe the oil flow
Slowly pour the measuring cup containing organic oil into another empty cup to observe its flow, and the oil flow of good quality motor oil should be slender, uniform and continuous; The spoiled oil will appear in a state of oil droplets.
Third, the hand induction has no foreign objects
The oil is poured between the thumb and the index finger twisted, the feel should be lubricated, no abrasive chips, no friction, if you feel a large friction between the fingers such as sand particles, it means that there are iron filings, sludge and impurities in the oil.
Fourth, the oil should be transparent and free of foreign matter
On a sunny day or choose a place with better light, use the oil inspection stick or oil gauge to pick up the oil and then observe the oil droplets against the sunlight, if you see no abrasive chips in the oil under the light, it can continue to function; If there are too many grinding chips, it means that the oil has deteriorated and cannot be used anymore.
Fifth, no peculiar smell
All the oils that have a large odor stimulation and odor are spoiled or inferior, and good oils should have no special odor and only slightly aromatic.
Summary of oil deterioration
Lubrication oil after deterioration is dark black, foamy and has appeared emulsification phenomenon, with the finger grinding, no viscosity, astringent or odorous, dripping on the white test paper is dark brown, no yellow infiltration area or a lot of black spots. If not replaced in time, it will accelerate the wear of parts, affect the service life, and even cause safety accidents, so it is important to check frequently whether the lubricating oil has deteriorated and replace the new oil in time.
Stay at home to get rid of the violation
![Attention owners! Don't use the oil like this again! Will exacerbate engine parts corrosion![fig]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)