The main function of automotive motor oils is to ensure the correct operation of the internal combustion engine (ICE). At the same time, their key feature is the formation of a protective film on the metal rubbing surfaces of the parts of the power unit in order to reduce friction. It is important to consider the viscosity of the lubricant, as this is one of the main factors in choosing an oil. And for this you should understand the decoding of API, SL, CF.
The absence of a lubricating layer between rubbing metal surfaces leads to an increase in friction force and, as a result, temperature, which can reach the peak of metal melting (there is even such a welding process based on this, but this is no longer the topic of this article).
Ultimately, it ends with the fact that all nodes are stuck and the piston group is already losing its efficiency. Also, other damage cannot be ruled out.caused by overheating and jammed parts.
API standard. What is it about?
The American Fuel Institute or American Petroleum Institute in 1969 developed a classification system for motor oils - API. At the same time, it is worth noting that those materials that are designed for gearboxes and automatic transmissions do not fall into this typology. This is the responsibility of the vehicle manufacturers themselves.
But actually, what does CF and SL mean by API? Lubricants that comply with this classification provide an increase in the wear resistance of the power unit of vehicles. But besides this, they also reduce the risk of its failure during operation. In addition, the use of high-quality oil can reduce fuel consumption, improve driving performance, and also eliminate extraneous sounds in the engine.
One of the main advantages of high-quality lubrication is to ensure the stability of the power unit at negative ambient temperatures. Another equally important quality is the reduction of harmful emissions.
Need for labeling
Why are all these oils actually marked? Well, firstly, a certain type of engine or transmission assembly needs its own “lubrication”. Secondly, the operating conditions of the material and other factors should be taken into account (in the decoding of API, SL, CF, all this is taken into account), which we will not focus on for now.
In the set of incomprehensible at firstthe look of the letters and numbers that are printed on the container with the composition is precisely the whole point. That is, this determines the possibility of using one or another oil for an engine or transmission. And since an important indicator of any oil is viscosity, the marking allows you to determine its class and the degree of this parameter, depending on the properties.
At first glance, it seems that everything is still more confusing, however, if you understand what exactly all these letters and numbers mean, then the overall picture is already emerging.
Deciphering marking symbols
Motor lubricants from a variety of manufacturers are currently on the market. There are among them those who have a worldwide reputation and the corresponding quality, while others are less known, but they can offer no worse option. Unfortunately, there may also be a "self-made", and it has not only a low cost, but also the quality is at the same level. Therefore, do not chase cheapness, as a result, costs can only increase.
Before you buy this or that lubricant, you must carefully study the label with the marking of motor oils. As a rule, it contains all the necessary information of the following nature:
- base used - organic, synthetic or semi-synthetic;
- oil quality and appointment according to API standard;
- viscosity values according to SAE classification;
- manufacture date;
- batch number.
With the choice of the manufacturer and the name of the engine oil, it is usually notthere should be difficulties - advertising and recommendations of specialists will serve as a decisive factor. The batch number and date of manufacture indicate the suitability of the formulation.
Although the lubricant is not a perishable product, you should nevertheless refrain from further use of the expired product.
API motor oil classification
Typology takes into account such parameters as the type of power unit, including its mode of operation, as well as the year of manufacture, conditions of use and operational properties. By standard, all oils are divided into two main groups with the corresponding designation:
- The "S" (or Service) category includes oils that are designed for use with gasoline engines.
- Another category - "C" (commercial in another way) corresponds to lubricants that are relevant for diesel power units, including road construction equipment and agricultural machines.
At the same time, each marking class according to the API system consists of two letters of the Latin alphabet. The first just indicates belonging to a particular engine, depending on its "power" - gasoline or diesel fuel.
As for the second letter in API SL and CF, it indicates the level of performance quality. And characteristically, the farther it is located, the better the properties of the oil.
Consumables for transmission unitsdenoted by the letter "G".
In total, there are 12 classes in this category according to the letters of the Latin alphabet from A to N (except for I and K):
- A - this type of oil differs from others in that it is allowed to use them not only in gasoline engines, but also in diesel power units. Only this group is so outdated that today it is practically not used. Previously, additives were not required for high-quality protection of parts, so SA API oils were widely used in their time.
- B - lubricant for low power engines. But since it did not provide adequate protection to bearings from wear, oxidation and corrosion, it is contraindicated in modern motors. Except when it is written in the instructions themselves.
- C - This brand of oil was popular among light and heavy vehicles from 1964-1967. The consumable can be used on old used cars.
- D - this type of lubricant was relevant for gasoline engines until 1968 of cars and trucks. Also considered an obsolete category.
- E - the brand is suitable for all power units that were produced after 1972.
- F - According to the API engine oil specification, this class is also considered obsolete. Such grease can be poured into engines after 1980 "birth".
- G - these oils are applicable to cars not earlier than 1989 of release. There are already additives that provide protection against corrosionprocess and rust.
- H is the best option for engines manufactured from 1994 and later. This oil is resistant to corrosion, carbon deposits, oxidation and wear. It is relevant not only for cars, minibuses, but also for trucks. Only the manufacturer's approvals must be observed (they are indicated in the instruction manual).
- J - these oils are intended mainly for engines produced after 1996 in relation to cars, sports cars, minibuses, small trucks. The oil perfectly retains its properties in the winter, however, when used, a little soot is formed.
- L - SL engine oil is one of the best options for most vehicles made already in the new millennium. This material is eco-friendly and energy-saving. It applies to multi-valve, lean-burn, turbocharged powertrains.
- M - This class was approved on 11/30/2004 and is intended for gasoline engines that are currently being manufactured. This option is better than API SL. The oil provides protection against oxidation and early wear. In addition, it retains its properties at low temperatures.
- N – approval date 01.10.2010. This lubricant contains a limited amount of phosphorus. It is fully compatible with many modern systems that are able to neutralize exhaust. The oil is an energy saving type.
This classification is widespread throughout the world.
Obsolete categories that are practically not used anymore (with rare exceptions) include oils with Latin letters from A to H.
Class C - diesel options
This category includes lubricants that already have a different marking - C:
- A. CA grease was used exclusively in lightly loaded diesel engines. This is also a relevant option for old used cars.
- B. The CB class was also adopted a very long time ago - in 1949 and was an improved version of the CA API.
- C. The date of the appearance of the CC category is 1961. It includes those oil products that can be poured into medium-loaded power units.
- D. The CD class entered service starting in 1955. Such oil has found wide application in relation to agricultural machinery - tractors, combines.
- E. CE class oils are applicable to diesel engines from 1983 or later. This is an actual option for use in very powerful turbocharged engines, where the working pressure is significantly increased.
- F-4. The CF-4 category includes lubricants that can be used in four-stroke diesel powertrains from 1994 and later. Such oil can also be poured into gasoline engines, if there are no opposite instructions in the car manual.
- F-2. API CF 2 class oil is designed for high-load two-stroke internal combustion engines operating on diesel in difficult operating conditions.
- G-4. According to alreadyfamiliar API standard, the CG-4 category was introduced 22 years ago. Such oil can be filled with highly loaded engines, where fuel with a sulfur content of not more than 0.05% is used. At the same time, the material is also relevant in cases where there are no special requirements for fuel quality (sulfur concentration can already reach 0.5%). In any case, this lubricant helps to avoid severe wear of engine parts, as well as soot.
- H-4. Category CH-4 introduced to the masses on 12/01/1998. The oil is the best option for use in engines operating in high speed mode, as it meets the requirements for the content of toxic substances in the exhaust. The composition of the consumable contains special additives that prevent the formation of carbon deposits and provide proper protection against wear.
- I-4. The CI-4 engine oil performance class was introduced 15 years ago. Such a lubricant is used in modern engines, regardless of the type of fuel injection, including the type of boost. And all thanks to the content of dispersing detergent additives. As a result, the oil is resistant to thermal oxidation and also has excellent dispersing properties. During operation, the amount of smoke decreases. The oil begins to evaporate when it reaches 370 °C. In terms of fluidity, the grease is suitable for use in extreme cold.
- I-4 PLUS. CI-4 PLUS grease has slightly improved performance - very little soot is formed, evaporates poorly and is practically not subject to oxidation under high temperature. Moreover, duringproduction lubricant passes up to 17 tests.
- J-4. This is the recommended engine oil for most engines, since the CJ-4 class can be called a modern consumable without exaggeration, although it was introduced about 13 years ago - 10/01/2006. Lubrication meets the requirements according to which engines were produced in 2007. At the same time, there are certain restrictions: ash content should not exceed 1%, sulfur concentration - no more than 0.4%, phosphorus content - less than 0.12%. These oils can be filled into many modern power units, as they fully comply with the introduced environmental standards.
Numbers are already indicated here in the marking of motor oils (usually 2 or 4).
This indicates that these oils are suitable for 2-stroke or 4-stroke engines respectively.
There is also a separate classification of engine oils according to API, which is suitable not only for gasoline engines, but also for power units running on diesel fuel. In this case, these lubricants are assigned two types at once, and in the marking they are separated by a slash "/" (slash). A prime example of this:
- API SJ/CF-4.
- API SL/CF.
- API SM/CF.
In this case, in the first place there is an indication of a more preferable application from the point of view of the manufacturer. From the examples above, we can conclude that the main use of motor oils concerns mainly gasoline poweraggregates. At the same time, there are no contraindications for diesel engines.
Let's take API SL/CF oil as an example. The first letter (S) indicates belonging to gasoline engines, the second (L) refers to the optimal quality class for vehicles. Issued since 2001.
Now let's turn to the second part of the SL CF API decryption after the slash ("/"). Here, the manufacturer allows the option of using oil in diesel engines. As evidenced by the letter C. Next comes the F indicator, which indicates the use of SUVs produced since 1994.
Many compatriots were surrounded by advertisements that introduce consumers to energy-saving oils. In addition, most car manufacturers recommend these particular lubricants for mass use. In addition, according to the assurances of the manufacturers of these motor oils themselves, their products save fuel while simultaneously increasing the resource of the power unit.
Such oils are characterized by low viscosity, and it does not matter in what state - cold or hot. At the very least, advertising claims can certainly be trusted: the tests actually show that the reduced viscosity is maintained over the entire temperature range. That is, it is actually the recommended engine oil that can be poured into many modern engines.
As for fuel economy, there is no doubt about it, since the liquid consistencydoes not require much effort from the engine and oil pump. Also due to this quality, costs are reduced in terms of oil film shear in main and connecting rod bearings, including camshaft bearings. Such a composition is more quickly discharged from the cylinders by oil scraper rings.
Difference between gasoline and diesel engine oils
On the one hand, it seems that there is no difference what to pour into a diesel engine - API CJ-4 or API SN. Many drivers do this. But in reality, it’s not for nothing that there are such markings for API motor oils - SL and CF. Which applies individually to these types of power units (with the exception of mixed options). In other words, due to the API specification, oils marked C should only be poured into diesel engines, and the letter S indicates belonging to gasoline engines.
This is mainly due to the fact that modern engines have very different operating conditions depending on the type of fuel. Of course, there are universal oil options on sale that are relevant for both types of motors (API SM / CF, etc.). It should only be borne in mind that such lubricants are inferior in quality to specialized counterparts.
How to choose engine oil for a car? Before being puzzled by this question, you need to know the technical characteristics of your vehicle well. What to pay attention to? First of all, remember that you should not judge the quality of engine oil based only on itsconsistency.
The hue may even change depending on the additives. In addition, the presence of these additives in a certain way affects the properties of the final oil product. Yes, some properties can be significantly improved, but again at the expense of other qualities.
If the lubricant darkens, then this indicates its excellent cleaning qualities. But it perfectly retains products as a result of incomplete combustion of fuel.
You should also always keep in mind a number of other equally useful tips:
- API SL CF does not allow oils of different bases to be mixed together.
- If necessary, replace the lubricant consumable, first flush the engine.
- Currently, there are a lot of counterfeit products of obviously low quality on the market. Although they are cheap, no one can give guarantees regarding their quality and effect on the power unit. It is better to purchase oil from manufacturers or their official representatives.
Modern engines are highly sensitive to petroleum products. Therefore, the choice of oils should be taken with all responsibility.
It should also be borne in mind that the API oil classes discussed in this article are forward compatible. In other words, each subsequent category overlaps the requirements of the previous one and oil can be poured into engines designed for obsolete grease.
For those interested in decipheringAPI, SL, CF, it is worth knowing that the standard has some features that do not have the best effect on the condition of old engines. The fact is that in modern oils the base number is reduced, especially for lubricants with a low degree of viscosity.
Motors with high blow-by gases need high-alkaline oils during operation with medium quality fuel.
Without a doubt, modern lubrication has the most favorable effect on the operation of power units. But again, this only applies to new designs and is certainly not an oil for older cars. It is clearly not worth choosing this option for engines that have already worked out most of the resource on old material.
It is no longer possible to increase the duration of the service life, and this is a fact! In addition, the cost of operation will increase significantly.