At present, the car park of the Russian Federation is mainly made up of cars whose engines and operating conditions require oils of the 5W30 or 5W40 category. Below is a brief look at 5W30 and 5W40 oils, what is the difference between them, whether they can be mixed, and which SAE grade lubricant is best for winter.
Decoding oil 5W30 and 5W40
Similarly, two numbers separated by the Latin letter “W” denote multigrade oils according to the SAE J300 classifier. In fact, the difference between the lubricants in question is small.
For 5W30 and 5W40 oils, the winter viscosity index is the same: 5W. This means that the oil has the following qualities during winter operation:
- viscosity when pumping lubricant through the system is guaranteed at ambient temperatures down to -35 ° C;
- viscosity when cranking the crankshaft will ensure that the engine is started with a starter and at the same time protect the liners and crankshaft journals, as well as the covers and beds of the camshaft from scuffing at ambient temperatures down to -30 ° C.
And for the two considered oils, this indicator is the same. That is, with regards to winter operation, there is no difference.
The so-called summer part of the SAE index refers to the kinematic and dynamic viscosity at the operating temperature of the oil. There are already significant differences here. 5W30 oil has a kinematic viscosity at 100°C ranging from 9.3 to 12.5 cSt, dynamic at 150°C is 2.9 cSt. For 5W40 oil, respectively, from 12.5 to 16.3 cSt and 3.5 cSp. 
Can 5w30 and 5w40 be mixed?
This question is not entirely correct, since other factors influence the miscibility of oils. But this question is still often asked by motorists. So let's give an explanation.
It is possible to mix oils with the same bases and similar additive packages without restrictions. For example, if you fill in hydrocracked synthetics (or semi-synthetics, if we take into account the Western classification) with a package of additives from Lubrizol, you can safely add oil with the same base and additives from Lubrizol. The difference will be only in the concentration of thickening components and a minor difference in other active substances. The oils will not conflict with each other. Moreover, this statement is true regardless of the oil manufacturer.
Do not mix 5W30 and 5W40 oils, which have a different nature of origin. For example, pouring 5W30 mineral water into high-quality PAO-synthetics 5W40 is undesirable. The differences between these lubricants at the molecular level are significant. Such mixing can lead to increased foaming, decomposition of some additive components, formation of ballast chemical compounds and their precipitation, as well as some other unpleasant side effects.
Which is thicker: 5w30 or 5w40?
Based on the first point, the answer to this question is: thicker oil with a viscosity of 5W40. Both in terms of dynamic viscosity (at high shear), and in terms of kinematic. However, it is impossible to unequivocally state that one of the oils is better or worse just because it is thicker.
The viscosity parameter is not evaluated only in the better/worse plane. In addition to the viscosity itself, which is definitely higher for 5W40 oil, such an indicator as the viscosity coefficient is important. This indicator characterizes the ability of the oil to maintain its viscosity over a wide temperature range. And the higher this indicator, the less the characteristics of the oil depend on temperature.
For example, with a viscosity index of 140 units, the oil will significantly change its fluidity with temperature. At negative temperatures, it will noticeably thicken, and at positive temperatures it will become more fluid. At the same time, a viscosity coefficient of 180 units indicates a lower dependence of viscosity on temperature changes. That is, the oil is more stable in terms of viscosity over a wide temperature range.
Oil for the winter: 5W30 or 5W40?
In terms of cold start safety, both oils under consideration will work equally well in the engine in winter. Guaranteed engine protection is provided at temperatures down to -30 ° C. There is no difference for winter operation, or it is insignificant.
What is the difference between the "summer" part of the viscosity index - we have analyzed it above. And how it will affect winter operation depends only on the engine itself. If it is designed to work with oil, which should have a high temperature viscosity of 30 SAE units - 5W30 oil will be better for winter. If the engine requires 5W40 lubrication, it is better not to experiment and pour it.
Which oil is better: 5W30 or 5W40?
Initially, the automaker lays down certain parameters in the design of the motor: gaps between the contacting parts, the maximum load in friction pairs, the roughness of the mating surfaces, etc. And the oil is selected in such a way that it penetrates the contact spots without problems, forms a reliable protective film and minimizes metal contact for metal.
Therefore, the conclusion here is simple: the best oil is the one that is initially more technologically advanced and of high quality and is recommended by the automaker. There is a small caveat here that not all motorists are aware of. The automaker for some car models may recommend different oils for different operating conditions or mileage. Therefore, it will not be superfluous to flip through the instruction manual again and look into the section with recommended oils.
There are many types of oils on the lubricants market today. The type of engine, the temperature of its operation, as well as the ambient temperature and much more determine one or another type of oil. Let's try to figure them out.
Viscosity is a fundamental property of motor oils. It is differentiated according to the SAE (USA) classification. Along with their classification, which is generally accepted, others are also used - operational classifications. These classifications have been developed by international automotive organizations. They set additional conditions for car oils, taking into account the results of numerous tests and advice from car manufacturers and car engine manufacturers.
Deciphering engine oil designations
The main such classifications are:
- API classification - developed by the American Petroleum Institute. He established the limits of various parameters (piston cleanliness, engine coking, etc.) using a variety of test facilities (engines);
- ACEA classification. It puts more stringent limits than the API classification. ACEA is also adapted to European vehicles and local operating conditions typical of the Eurozone;
- The ILSAC classification is the result of the efforts of several international organizations and represents the categories of the API classification.
The type of oil is determined both by its viscosity and its change with temperature. Based on this, the following oils are distinguished:
- WINTER- the low viscosity of winter oil facilitates the "cold" start of the engine at negative (and not higher than 0) temperatures. The disadvantage of this type is poor lubricating properties at elevated temperatures (in summer);
- SUMMER‒ a relatively high level of viscosity makes it possible to provide lubricating properties at elevated temperatures (including in summer). The disadvantage of this oil is the aggravation of engine operation during the cold period;
- ALL SEASON- has the best viscosity properties due to the improved composition. In cold weather, it shows the qualities of winter oils, and in summer - summer ones.
Today, it is it that is increasingly capturing the market, since this type of oil does not require a constant need for a “seasonal” change before winter or summer.
However, not only the viscosity characterizes the oil, it is also determined by its cleaning (washing) properties, preventing oxidation and corrosion. In the presence of any additives (cleaning, anti-corrosion, etc.), the final cost of motor oils changes.
SAE classification
Types of motor oils
Oils depending on viscosity are divided into:
- WINTER: SAE O - 25W (step 5)
- SUMMER: SAE 20 - 60 (step 10)
The letter “W” in the index of the winter index of use indicates the period of use of the oil, from the English Winter - winter.
Consider, using the example of 5W30 and 5W40 oils, what the SAE classification means and how these oils differ.
First, let's determine that if an oil has an indicator of summer use (for example: 5W) and an indicator of winter use (for example: 30), then such an oil is all-weather.
From this it turns out that both oils are all-weather, what is the difference between 5w30 and 5w40?
5v30 or 5v40, which is better?
Comparing the two selected oils, it turns out that the 5W40 oil has a higher summer use index (40>30) than the 5W30. This means that the protective film formed by the 5W40 engine oil will be better preserved when the engine temperature rises during the summer period. At elevated oil temperatures, the viscosity of 5W40 is 1.5 times higher than that of 5W30, which has a positive effect on engines with higher thermal stress, as it retains its properties well.
And in turn, the temperature range 5W30 is shifted lower in comparison with 5W40. This shows that the oil has a lower viscosity. Therefore, it is preferred for use when starting the engine in cold weather, and at high temperatures it becomes too liquid, accompanied by a loss of lubricating properties.
By the way, do not neglect the index of winter use of all-weather motor oils.
Therefore, when choosing engine oil, you should be guided by the recommendations of the car manufacturer, as well as the expected operating temperature of the car. In the case of comparing 5w30 and 5W40 oils, they are equally suitable for engine operation in winter conditions at temperatures up to -25 ºС, however, when the use temperature rises in summer, 5w40 oil wins.
January 2, 2017The modern market of the auto industry is so wide and varied that it is sometimes difficult to choose one or another product. Need the help of a knowledgeable consultant, or have experience behind him. This applies to any spare part for a car: brake pads, cooling system fluid, battery, type of lubricant for the motor, when choosing the latter, many motorists have the most questions. In addition to standard mineral, semi-synthetic, synthetic bases, there are many modifications according to the type of viscosity. For many car owners, it is customary to see the number 40 after the letter character. But, if the indicator is in the form of the number "30", then this causes concern due to insufficient theoretical knowledge. Not every driver will be able to give a reliable answer to the question: what is the difference between 5W30 and 5W40. We will discuss all the subtleties of this difference below.
Relevant only at negative degrees
Indeed, 5W30 is useful to a motorist only when frost sets in. It is not recommended to use the product in summer. Some geographical regions of the country are distinguished by a special climate, where temperatures start up to -60 ° C, and the average does not rise above 25 - 30 ° C. So, we know that 5W30 is intended for use at temperatures from 25°C to +20°C. While, familiar to us 5W40, calmly endures a similar frost, and heat with a mark of + 35 ° С. Both types have the letter "W", which, according to international standards, means that they can be used in winter. Sometimes even experienced specialists can get confused in modifications, not like “recruits”.
Criterias of choice:
- vehicle type;
- age;
- mileage;
- climatic operating conditions.
Oil types
- Summer: increased viscosity is characteristic, since positive temperatures contribute to an increase in fluidity. The density of the lubricant must be such that it can cover the working surface of the metal part with a film, preventing wear. Such characteristics are relevant only for the summer period;
- winter: the consistency is thinner than that of the previous species. Thanks to this, the electric starter of the car easily turns the crank mechanism of the engine, even at harsh “degrees”. The lubricating fluid in a matter of seconds will scatter throughout the motor, enveloping the surfaces of the parts;
- all-weather: the most popular option among all the others for the reason that the liquid is used all year round. Division by season does not occur. Motor lubricant performs all the same functions as the previous two types. Synthetics 5W40 is considered to be all-weather.
Properties by which classification occurs
- Viscosity: the main and important indicator for all chemicals;
- international classifier according to the API system: the chemical basis of each lubricant includes many thickeners, due to which the oil product is divided into three types according to the temperature regime. In oil products of a universal type, the quantitative and qualitative composition of additives corresponds to 50/50.
According to the digital indicator indicated after the letter symbol, you can "read" the content of thickeners in the base. In other words, to understand how long the film is held on the metal surface of the assembly. The property is important for the full performance of the motor and the duration of its operation.
Before you buy a lubricant, be sure to consider factors such as: the age of the equipment, the actual mileage. If the car is not more than five years old, and the mileage is not higher than 75,000 km, then it is better to fill in synthetics with a viscosity index of "30". But, some automakers clearly indicate the need to use 5W40. This is written in the owner's manual for the specific vehicle.
However, if the equipment has traveled more than 100,000 km in the overall standings, then fill in only 5W40 here, since there is wear on metal parts, wear in the piston group. The use of a lubricant with a higher viscosity will only increase compression, increase performance by temporarily filling holes and gaps.
Timing and replacement
There are no exceptions. Intervals as recommended by the car manufacturer. For 
synthetic bases interval is 25 - 30 thousand km. run. Depending on the specific conditions of use of the equipment, the mileage range can be reduced, but not increased in any way. It is allowed to exceed the specified limit only by 500 km. This should be strictly adhered to when the machine is under warranty service from the manufacturer.
Product protection
We do not always buy high-quality and original goods. The reasons are different: personal unwillingness to spend money, a lot of counterfeit goods, and other points. Not everyone can distinguish an original from a fake, especially when a person is inexperienced. What can I say if fraudsters manage to successfully sell banknotes to banking institutions. First of all, pay attention to the general appearance of the oil canister, the integrity of the label, the quality of the sticker, and the clarity of the image. It will not be superfluous to ask the seller to provide a quality certificate for the goods. Ask for the region of origin, the name of the supplier. Ask for recommendations in the circle of your acquaintances, friends, comrades in the garage. By combining several opinions, you can add up the big picture and make the right choice. Best wishes. See you soon. Wise decisions for you.
The question of what kind of oil to fill in the internal combustion engine of your car arises in front of almost every motorist. For example, which is more appropriate to choose - 5w30 or 5w40? What is the difference between 0 and 5w30?
Which lubricant will be more “to your taste” for a particular motor in the summer or for the winter? Can fluids of different brands or viscosities be mixed? How not to get lost in the "jungle" of an exorbitant abundance of lubricants? This article aims to answer these and similar questions.
Of course, the best choice is the lubrication option proposed by the auto manufacturer - no one argues with this. And if for some reason there are no recommendations? Or is the car not one of the latest "extra-fashionable" models? Not all old engines are suitable for modern high-tech oils.
And another very interesting moment is when the opinions of the manufacturer (official service-man), the seller of the car oil, as well as the service station specialist, radically diverge, and the car owner is lost in conjecture: which oil is better to fill.
In such situations, an independent understanding of the properties and characteristics of fuels and lubricants will serve as a good help for the right choice.
It is always easier to understand with a specific example, so let's try to make a comparison of two fairly popular lubricants and find out what is the difference between 0 and 5w40. At the same time, along the way, let's try to decide which oil is better than 5w30 or 5w40 in winter.
A tour of the main parameters of consumable liquids.
There are two key parameters for classifying oils - this is the base base (determines the basic properties of the lubricant) and additives that improve the natural characteristics of the base (in particular, they serve to provide the specified viscosity indicators in a certain season of the year).
On a basic basis lubricants have three categories: mineral, synthetic or semi-synthetic. In the modern market, 5w30 engine oil, as well as 5w40 oils, can be found in any of three classifications.
Synthetic materials have higher quality indicators than semi-synthetic ones, and the latter, in turn, provide better operating conditions than mineral ones. In this classification, it is impossible to determine which is better - 5w30 or 5w40 - only by a numerical designation.
Here, the category it belongs to, as well as the specific manufacturer and the quality of the additives used, will play a big role. By the way, both 0 and 5w30 are universal lubricants and are suitable for both diesel and gasoline engines.
In addition, they are completely interchangeable from different manufacturers and can be mixed if both oils are suitable for the design features of the engine in terms of viscosity, since both options meet all international standards.
According to seasonal preferences, lubricating fluids are usually classified according to the internationally accepted international system SAE (Society of Auto Engineers of the USA), which offers tables for a clear separation of lubricants depending on the change in viscosity from temperature changes.
According to SAE classification There are three classes of motor oils:
- summer, have a high viscosity index, are designed to provide a sufficient thickness of the lubricating film on the parts of power units (inside the assembly), high-quality wear protection and normal operation of oils during engine overheating, in conditions of positive outside temperatures. Designated only by numbers (SAE 20,30,40, 50,60);
- winter, are characterized by low viscosity, which allows such a product to be poured into the engine in winter and the engine will start unhindered at sub-zero temperatures. At the same time, due to the low viscosity, a thinner film will remain on the engine parts at high speeds, which significantly reduces the wear-resistant properties of the power unit. They are designated by numbers and the letter "W" (from the English "winter" - winter), an example of SAE 0W, 5W, 10W, 15W, 20W, 25W);
- All season, meet the requirements of the summer and winter period and are used at any time of the year, because capable of maintaining good performance over a wide range of temperatures, this grease performs without the need to change it at the end of the season. They are designated by two digital values and the letter "W" between them (0W20, 5W30, 10W40, etc.).
Despite the fact that seasonal oils exist, in practice they are in consumer demand, and, accordingly, they are offered for sale, mainly all-weather oils. Let's figure out how to decipher 5w30, 5w40 oils? What class of characteristics do 5w30, 5w40 oils have? Which one will be thicker, and which one will be thinner?
What does the label say
So what is similar and how does 5w30 oil differ from 5w40? Let's start by deciphering these two marks. In the marking of both there are two numbers and the letter "W". This means that by belonging to the seasonal class there is no difference between 5w30 and 5w40 - both oils are all-weather fuels and lubricants.
The number "5" in front of the "W" shows the winter parameter, which allows you to calculate the minimum allowable cold start temperature of the engine. For the calculation, it is necessary to subtract the number 35 from the number before “W”, in our case, subtract the number 35 from 5: we have 5−35 = −30 - this is the minimum allowable temperature for free cranking of the crankshaft by the starter and pumping lubricant with an oil pump under pressure during a safe cold start.
And although in the circle of motorists there is an opinion about the number 40 (and not 35), then in this case we will no longer talk about the “permissible”, but about the “critical” engine start temperature. As we can see, 5w30, 5w40 oils do not have differences in the first digit, therefore, the substances in question will behave identically in frosty weather.
If we consider 5w30 and 5w40 oils: what is the difference when used in the summer, then by the difference in viscosity indexes at high temperatures, we can say with confidence that 5w40 engine oil is more viscous.
We see summer indices on the marking after the letter “W”. This means that a thicker film will remain on the surfaces of rubbing parts in an engine where 5w40 is used than when filling with 5w30 oil. Here you will have to rely on the recommendations of the manufacturer.
A few words about the interchangeability of 5w30 and 5w40 oils.
If both oils are indicated in the user manual, then you can choose any of the expediency of use. But is it possible to fill in 5w30 instead of 5w40 and vice versa?
Consider what this can threaten for the motor:
- recommended 5w30, filled in 5w40 - due to the increased one, it may not “push through” through all channels, which will force the internal components of the engine to work in conditions of “starvation”, and most likely will lead to premature wear, an increase in the operating temperature of the engine, a decrease in engine life;
- recommended 5w40, poured 5w30 - too thin film remains on the rubbing surfaces of internal parts due to increased fluidity of the lubricant, which can lead to wear of piston rings and cylinders.
Viscosity at high temperatures is a measure of the minimum and maximum viscosity at a particular shear rate specified in the SAE table. So for 5w40 oil, its minimum value reaches 3.5, and for 5w30 K - 2.9. The maximum (kinematic) viscosity for 5w40 is 12.5-16.3 cSt, and for 5w40 it is 9.3-12.5 cSt.
To the above, we can add that there is another criterion by which to compare - this is the oil change interval. The greater the spread between the extreme figures (winter and summer parameters) indicated on the label, the more often you have to change. From which it follows that the 5w40 oil change interval is shorter.
In conclusion, I want to wish everyone who is driving that his “iron horse” is always in good condition and brings only joy to the owner. And I think you will definitely take care of it.
Sometimes the manufacturer in the technical documentation supplied with the car does not indicate the specific SAE viscosity that is recommended for use in a particular engine, but several acceptable options. For example, 5W-30 and 5W-40.
What is the difference between 5W-30 and 5W-40 in practice and how to choose the optimal viscosity without harming the engine?
To answer this question, it is necessary to consider in more detail what SAE viscosity indicators include, how they are calculated and what semantic load they carry.
How 5W-30 and 5W-40 are deciphered
Before delving into technical and physical details, let's recall what the SAE viscosity rating means, if we take into account the knowledge of a wide range of motorists. For ordinary car owners, the SAE engine oil class indicates the temperature ranges in which it is used.
SAE classification revised
The viscosity parameter includes 2 indices: summer and winter. The first, which with the letter "W", determines the winter viscosity properties, the second, which is written with a hyphen - summer. There are tables in which, according to the SAE class, the ambient temperature range acceptable for car operation is indicated.
- winter -30 °C;
- summer +35 °C.
For lubricants of the 5W-40 category, this range is somewhat wider:
- winter -30 °C;
- summer +40 °C.
However, all of the above assumptions are conditional. That is, the SAE viscosity indicators themselves and their interpretation in relation to ambient temperature are very superficial characteristics that do not carry a really significant semantic load.
And these temperature limits are not rigid and can shift in one direction or another, depending on a large number of factors.
Moreover, the real, operational difference between 5W-30 and 5W-40 can be both quite large and insignificant. Let's take a deeper look at how these viscosity parameters are determined and what they affect in practice.
Methods for determining viscosity
The category to which this or that oil belongs according to SAE includes a whole range of indicators. For example, for winter viscosity, there are two main criteria that determine the index before the letter "W":
- cranking viscosity;
- pumping viscosity.
The cranking rating means how easy it will be for the starter to turn the crankshaft in winter, immersed in frozen oil.
This parameter is measured in a special device - a rotational viscometer (CCS). The essence of the device is to simulate the conditions of cold cranking in the engine and measure the resistance of the lubricant to cranking. For the 5W-30 and 5W-40 oils under consideration, the difference is small or almost non-existent.
The pumping rate indicates how much resistance the thickened oil has to the pump's attempt to drive it through the system. Measured on a mini-rotational viscometer type MRV.
It also creates conditions that resemble the process of pumping oil through the system. Lubricant under pressure is driven into the channel and the resistance to this process is evaluated. Between the oils discussed in the article, the difference in this parameter will also be small.
It is important to understand that for lubricants with an index of 5W there are no strictly defined viscosity values for pumping and cranking.
There are certain values, beyond which the measured values should not go at the regulated temperature.
That is, different lubricants with an index of 5W-30 or 5W-40 may differ in low-temperature viscosity, but in any case ensure the normal operation of the motor at the temperature indicated by the standard.
For example, for 5W, the low temperature viscosity when measured for pumpability should not exceed 60,000 mPa s at -35 °C. When measured in rotation, the value of viscous resistance should not be less than 6600 mPa s at -30 °C.
This indicator can be as close as possible to the border indicated by the standard, or be much lower.
High temperature viscosity is measured at 100 and 150 °C. The priority is the indicator calculated for 100 ° C, that is, at normal operating temperature. It is measured in cSt (centistokes).
There is a significant difference between 5W-40 and 5W-30 oils:
- for 5W-30, the value of high temperature viscosity, measured at 100 ° C, is in the range from 9.3 to 12.5 cSt;
- for 5W-40, this figure is limited to 12.5 and 16.3 cSt.
That is, a 5W-30 oil with a minimum threshold of 9.3 cSt is almost 2 times more liquid at 100 ° C than a 5W-40 oil with a value of 16.3 cSt.
Based on these values at 100 °C, one of the key indicators of lubricant stability is calculated - the viscosity index.
What SAE classification means in practice
In practice, the complex characteristic embedded in the SAE classifier means not just the temperature range in which the lubricant in question can be operated. 
If everything is more or less clear with the winter part of the designation of universal oils 5W-40 and 5W-30, then how to interpret the summer designations 40 and 30? Here the answer will be the most general and meaningless: temperature limitation during summer operation.
In fact, the summer viscosity limit is very conditional and indirectly related to other, more understandable reasons:
- thicker lubricants are better retained on the surface of rubbing parts at a higher temperature, while low-viscosity oils in the summer heat when the car is idle in a significant amount drain into the sump;
- in summer, the overall oil temperature is slightly higher in the engine, as the heat rejection gradient is lower in summer due to the smaller difference between engine temperature and ambient temperature.
That is, thick lubricants in summer, in theory, have higher protective properties. However, everything is not so simple here either. Almost everything is linked to the design features of the motor.
Engine oil splash lubrication
For example, if the design clearances in the engine are larger initially, then thicker oils will work better in the engine at the same ambient temperature.
The film will be thicker and more reliable. For small gaps, on the contrary, too thick lubricants can not penetrate into the gaps intensively enough and thereby expose the engine to the risk of dry friction.
Therefore, the difference between the viscosity of 5W-40 and 5W-30 oils in relation to each individual motor can be both significant and play practically no role.
What is the difference between 5W-30 and 5W-40
The difference between 5W-40 and 5W-30 oils in practice comes down to high temperature viscosity. That is, at engine operating temperature, 5W-30 grease will be more liquid than 5W-40.
Whether this is good or bad, only the engine manufacturer knows for sure. It all depends on the design features and the nature of the load in the surfaces protected by the lubricant.
The thicker 5W-40 oil generally performs better where clearances are larger and contact loads are higher. Also, for hot climates, 5W-40 grease will remain in the working interfaces in the amount necessary for a safe start-up longer.
5W-30 engine oils are thinner at operating temperature. This allows the lubricant to better and faster reach the rubbing surfaces through the channels of the oil lines.
On the other hand, when using a liquid lubricant in engines that are not intended for this, especially in the southern regions, a drop in oil pressure in the system may be observed.
Insufficient pressure is fraught with a sharp decrease in the amount of oil supplied to the rubbing surfaces and, as a result, the appearance of metal-to-metal contacts.
In general, 5W-30 lubricants, unlike 5W-40, have a higher viscosity index. An oil with a higher viscosity index is more stable and behaves predictably with changes in operating temperature. Today, this factor, especially for modern forced motors, plays a significant role more than ever.
What viscosity oil to choose
Today, many motorists, answering the question of what viscosity to choose a lubricant, strictly adhere to the manufacturer's recommendations. In general, this is the correct strategy.
The manufacturer conducts a large number of tests before releasing the engine into mass production with the oil recommended by the designers. And during these tests, it is determined which viscosity will be most favorable for any possible operating conditions.
How to choose oil based on the marking of the canister - video
This is where the so-called “fool-proof” works. After all, it is obvious that cars manufactured by well-known automakers drive both in hot deserts, where the temperature rarely (or never) crosses the zero mark, and in the conditions of the far north.
And it becomes clear that from the available range of lubricants it is impossible to choose the oil that would equally well meet the requirements of a hot, desert climate and at the same time the conditions of the Far North. Greases of the 0W-60 class, covering all possible conditions, do not exist in nature.
However, automakers usually do not include huge instructions in the auto service book with an algorithm for selecting lubricants for various operating conditions. As a rule, they are limited to one or two suitable SAE classes and make a reservation for "special operating conditions".
Oil 5w30 or 5w40 what is the difference expert video will tell
Even when choosing a lubricant, such a factor as the degree of engine wear indirectly affects. If a new motor from the conveyor definitely has fixed gaps for which oil is selected, then after a run of 200-300 thousand, these gaps can increase significantly.
And the initially recommended lubricant, for example, 5W-30, can no longer create a reliable film in these conditions. Here it will not be a mistake to choose one point thicker oil: 5W-40. Especially if the car is operated in the middle or southern lane.
Therefore, when choosing between 5W-40 and 5W-30 oils, consider:
- first of all - the recommendations of the manufacturer;
- in the second - climatic conditions;
- in the third - the degree of engine wear.
Sometimes car owners consciously, even for relatively fresh cars, select a less thick oil. This is done to remove additional power from the engine or some fuel economy.
After all, a less thick oil requires less energy to overcome the forces of internal friction. However, such a solution may result in accelerated wear of the parts of the cylinder-piston group.
Any experiments with engine oil viscosity should be well thought out and strictly verified. And it is best to seek the opinion of an expert in this matter.
