These two questions, which categories need to be replaced and which categories really don't, should bother many novice drivers. Before the auto repair industry has reached high standards and standardization, in order to prevent being fooled, we must master the following knowledge points.
0 1 basic category
Mechanical oil filter and two sets of air filter fuel filter elements are categories with high replacement frequency in daily maintenance, but the replacement frequency of the latter two is much lower. The oil change interval should refer to mileage, not time period. The so-called "oil is easy to deteriorate after a long time" is lack of theoretical basis.
The finished engine oil contains more than ten kinds of additives, including "antioxidants"; Engine oil injected into the engine crankcase can come into contact with very little air. Only when facing the air of "blowby and forced ventilation" system at work can there be more air in the small crankcase after flameout and cleaning. However, under the normal air pressure standard at an altitude of zero meters, the oxygen concentration in the air is only 20.94%. The higher the altitude, the lower the oxygen concentration, so there is no need to worry about the oxidation and deterioration of engine oil.
If you must give a period of time, most of the engine oil can be used for 2~3 years; For example, the recommended oil replacement cycle of many cars in Europe and America is 36 months. The recommended cycle will certainly ensure that the oil in the later period still has qualified lubricity, sealing and corrosion resistance, otherwise it will affect the engine, which shows how long the service life of the oil is.
As for the mileage cycle, I don't need to go into details. The full synthesis can be used at ≥ 10000 km, and semi-synthetic engine oil has the same standard for NA vehicles. For turbocharged engines, the mileage is at least 5000km, and it is no problem to slightly exceed the mileage.
However, attention should be paid to replacing the mechanical filter element when changing oil, because the mechanical filter element is a filter element for storing impurities such as worn metal chips, and the internal "stock" will reach the threshold after long-term use. If the mechanical filter element is not replaced, there will be too much debris mixed with engine oil in the next car use stage, which will affect the lubrication and wear reduction effect; At the same time, the old oil stored in the mechanical filter is excessively mixed with the new oil, which affects the service life of the oil.
Two sets of air filters include: engine air intake system air filter and air conditioning system air filter.
The air filter is always a paper filter element, which is used to filter impurities in the air; Generally speaking, under the premise of not damaging the filter paper, the engine air filter can be removed and cleaned at least with 10000 km and 5000 km, and it is good to blow the dust with a hair dryer.
But it is difficult to feel any change without cleaning, because the suction pressure of the engine is large enough, and it is difficult for the filter paper to reach the degree of blockage within 10 thousand kilometers; Therefore, it is no problem to replace it with 1 10,000 kilometers, and some models are allowed to use 20,000 kilometers.
It is suggested that the air conditioning filter element should be disassembled and cleaned every 5000/ 10000km, and the replacement standard can be extended to 00000km. It is recommended to clean the filter element, because this group of air filters may produce peculiar smell, because the inhaled air humidity is different, and the high humidity air inhaled in wet or rainy season will make the filter element wet, and the wet environment is the best state for breeding mold.
The mold spores will produce peculiar smell after rotting, and the peculiar smell is always more prominent when using external circulation, especially warm air; Because high temperature will increase the intensity of molecular movement, the stage of using warm air will feel uncomfortable. Therefore, regular cleaning is necessary. The air conditioning filters of most vehicles are under the glove box of the co-pilot, so it is very difficult to remove and clean them, and they will be exposed to the sun after cleaning.
The replacement standard of fuel machine filter is longer: the external filter is replaced by 30,000-50,000 kilometers, and most of the internal filters are maintenance-free.
The function of fuel filter, as its name implies, is to filter impurities in gasoline and diesel; However, when the fuel is discharged, the first coarse filtration will be carried out, and the standard of ≤ 180 mesh can prevent 80 micron objects from entering the fuel tank. Generally, tankers have a filter element of about 500 meshes, and dust below 25 microns will enter the fuel tank of the car.
However, these dust impurities are not only rare, but also have little effect on the multi-point injection engine with average performance. Only a few in-cylinder direct injection superchargers require high fuel quality. Because the particle size of atomized oil droplets sprayed by high pressure can be lower than 10 micron, it will be equipped with a 2000/2500 mesh filter, and its service life is close to 30,000 kilometers, and that of other vehicles is close to 50,000 kilometers.
The built-in fuel filter has a long service life, but it is also long; Because this design is "stupid", the filter element is concentrated in the oil pump in the oil tank. If you want to remove and replace the filter element, you must first remove the back seat, then remove the oil pump from the oil tank, and finally remove and replace it. The external type can be replaced from the chassis as long as the body is lifted.
Therefore, the service life of this filter is forced to be extended a lot, and some vehicles have maintenance-free standards; However, there is no guarantee that it will not block and affect the oil pressure in the later use process, which is why the built-in design will only be used by a few European cars.
02 remaining categories
1: The unconventional categories of normal maintenance are as follows.
Anti-freezing coolant for 3 years (lasting for 6 years) Transmission oil and filter-60,000-80,000 km steering gear booster fluid-30,000 km (electronic power system without booster fluid) Brake oil-30,000-50,000 km (self-adjustable according to whether the braking force changes) Differential oil-80,000-65,438+/kloc-0.00 million km (one for rear drive and four-wheel drive is anti-freezing coolant, not only regularly,
Because the solution will evaporate normally, the liquid level should not be lower than the lowest line of the expansion kettle (make-up kettle) and should not exceed the highest line. It can be supplemented with distilled water, because the main part of evaporation is water, but the water wants to choose the impurity-free type of magnesium hydroxide and calcium carbonate; After adding water for three times, you can add the same type of antifreeze coolant once.
The oil change cycle of gearbox oil is very long, and most household scooters with little mileage do not need to consider the maintenance of gearbox in the general oil change cycle. On the other hand, if the car is still used for a long time, it is necessary to choose the right way to change the gearbox oil; It is generally recommended to adopt "circulating oil change", that is, use an oil change machine to pressurize new oil into the gearbox and squeeze out the remaining old oil.
In fact, this method will damage the gearbox, because it will be worn when starting the gearbox when changing oil; The ideal way is the simplest way-gravity drainage. As long as the filter element is replaced at the same time, the old oil can be cleaned.
2. Unconventional categories of soft candy standards.
Engine oil additive × fuel oil additive × hydrogen and oxygen decarbonization × engine cleaning × other rarely heard categories do not need to consider that the finished engine oil and fuel have high enough quality. It is ridiculous to say that the performance of engine oil needs to be improved. It is important to know that most cars do not use these additives, but the working conditions will not be worse; Because if the finished engine oil cannot effectively protect the engine, these oils cannot be allowed to be sold on the market.
Other additives, detergents and carbon removal methods will damage the engine more or less. Normal carbon removal should be disassembled and cleaned, or dissolved and cleaned by hanging bottles with high pressure. Some of the remaining maintenance projects with strange names are basically fools. There are not many types of maintenance for fuel vehicles. For car owners who keep changing cars for about 5 years, they only need to consider three filters and one oil.