Most motorists when buying a car are interested in the consumption of lubricants. Can the answer to this common question give an unambiguous assessment of the technical condition of the "iron horse"?

It is generally accepted that increased oil consumption in the engine indicates that not everything is in order with the machine. In the case when the flow rate increases sharply, and topping up is carried out on an ongoing basis, it is clear that the cause should be looked for, inspection, diagnostics and repair should be carried out. Usually the car owner is tuned to the standard indicators determined by the manufacturer, but when he looks at the dipstick and sees an overrun, the first thing that comes to mind is the thought of a breakdown and upcoming large investments. In addition, these are additional costs for car maintenance. Periodically checking the lubrication level should be taken as a rule, but let's look at the causes of excessive oil consumption in the engine.

Where does the oil go?

Increased oil consumption in the engine does not always indicate its deplorable state, in addition, its unchanged level also does not indicate the normal state of the engine. All internal combustion engines must consume fuel and lubricants, the question is how much it takes. There are several reasons for different volumes of consumption, but they can be conditionally divided into two groups:

• Established, associated with the design feature of the engine;
• Non-standard, indicating the wear of parts and failures in the settings.

Large-volume internal combustion engines, especially V-shaped ones, are distinguished by increased oil consumption than in small-capacity single-row engines. To prevent dry friction, the autolubricant forms a protective film on the cylinder walls to lubricate the piston rings, and accordingly burns out in new engines. In general, manufacturers of engines and oils strive to provide maximum protection for rubbing surfaces while minimizing waste.

Lubricant inevitably seeps into the combustion chamber as the pistons and valves move. Inevitably, oil is wasted on the intake through the crankcase ventilation system, crankcase gases carry out a small amount of lubricant. Turbocharged engines require lubrication of the turbine parts. The most banal reason for increased waste: if the lubricant did not burn out, then it leaked out, hence the high oil consumption.

In this article, we will not delve into the diagnosis of leaks, the replacement of oil seals and gaskets, but will focus on waste.

Diagnosing Excessive Oil Burnout

The simplest diagnostic technique to assess lubricant waste is a visual assessment of exhaust gases. If car oil enters the exhaust system, then the exhaust at high speeds is a bluish smoke, the combustion of high-quality gasoline does not give such a color to the gases. For comparison, in case of failures in the injection system, black smoke is emitted from the exhaust pipe, these are already symptoms of another disease.

There is another way to detect the constant burning of the suit over a long period: a black oily formation grows on the edges of the exhaust pipe. You can more accurately determine the ingress of oil into the exhaust system by diagnosing using a gas analyzer.

Assess your driving style. The operating mode of the internal combustion engine directly affects the oil consumption in the engine. When working at high speeds, the pressure and temperature of the lubricant increase, when heated, its viscosity decreases, therefore, more lubricant seeps into the working cylinders, which entails increased oil consumption.

Many are mistakenly tied to the consumption rate per thousand kilometers. Operation in the urban cycle is marked by a constant change in speed, frequent starting and stopping of the engine, idle idle, which is different from driving on the highway. Uniform movement at a speed of about 100 km / h in fifth gear and the manner of driving at high speeds with constant overtaking will show different fuel consumption, different waste.

It is much easier to come to the conclusion that the lubricant burns out above the norm than to identify the cause that explains the increased burnout.

The main reasons for engine oil to burn in the engine

1. Wrong oil filled. It is not suitable for your engine. If the suit is too liquid, then its leakage into the combustion chamber is inevitable. Viscous oil will form a thicker film and remain on the inner surface of the cylinders, more "soar" and burn. They cannot boast of properties that reduce volatility, low-quality oil fakes and fakes. I am glad that flushing the engine and changing the oil will help eliminate the first cause. For DVZ with high mileage, it is recommended to change synthetic oil to semi-synthetic, often this helps to reduce consumption. Be sure to follow the recommendations of the car manufacturer.
2. Deterioration of oil seals (or valve seals) due to poor-quality rubber, temperature changes or structural failure due to the use of unsuitable lubricants. Valve seals are inexpensive, and their replacement is not very laborious, but this operation significantly reduces oil waste.
3. Wear of piston rings. The problem is eliminated by replacing them, and this is already a major overhaul. In some cases, decarbonization helps, that is, a short-term engine load at maximum speed, more often such a procedure can remove carbon deposits from the rings if the car has not been used for a long time. There is a wide offer of special auto chemicals on sale, but sellers will not be able to guarantee a positive result of decarbonization, and they will prefer to remain silent about the effect of additives on motor resources.
4. The development of cylinders, namely the wear or damage to their inner surface. In this case, without resorting to an engine overhaul, you can change the oil to a more viscous one and put up with constant topping up, still cheaper than an overhaul. This measure is temporary, and the most correct solution would be to replace the entire engine.
5. Due to the destruction of the inter-valve bridges on the piston, the sealing of the combustion chamber deteriorates, as a result of which the pressure of the crankcase gases is injected, and the oil is carried out of the crankcase through the engine ventilation system through fuel injection.
6. For turbocharged engines, there is another reason: the increased oil consumption in the engine is affected by a malfunction of the turbine, so repair or replace it.

Topping up or replacement?

Some motorists believe that with constant topping up of oil, it is updated, and you can ignore its next replacement. This is fundamentally wrong. It must be changed according to the regulations, since the filter is clogged and washed-out combustion products accumulate in the pan, which do not go anywhere.

With the beginning of spring, more and more motorists begin to drive at higher speeds. The number of car owners who complain about the increased appetite of the engine for oil is increasing. Many complain about excessive consumption of it for no particular reason. I would like to understand why the engine eats oil

After all, the appetite of the motor can be moderated or the problem of increased consumption can be avoided. You just need to know something.

All such products are divided according to their structure. Some have properties to burn, others are more resistant to combustion. The first are completely original motor lubricants, the second are derivatives of them. To determine the durability of an oil, you need to look at the additive that helps to cope with the aging of this product. However, the use of various additives entails a qualitative loss in the properties of the oil.

There may also be leaks. These are quite popular reasons for increased consumption.

Big expense: how much

Car owners often ask questions about the consumption of this product by the engine. One such issue is the consumption of one liter of oil per 1000 km. Is it a lot or maybe a little? I must say that in each case it is completely individual. For many V6 or V8 engines, a liter of oil is actually the usual consumption rate. For the bulk of cars, a liter of oil is not just a lot, it's a lot. You need to know that each motor, even brand new and just off the assembly line, eats a certain amount of product. Oil can also drip or leak, burn in cylinders or accumulate on the walls. This is directly related to the direct purpose of the product. They must create a lubricating film on surfaces, protect engine parts from dry friction. This film burns perfectly in fuel combustion chambers.

The only question is how much product will burn in any particular motor, and how to solve this problem. Many car enthusiasts, owners of used cars, argue that it is necessary to add oil to a worn engine as it is consumed, rather than spending serious sums on overhauls. It's much more profitable.

Usually, car mechanics claim that the main reason for increased engine appetites is significant wear of parts. However, there are many different reasons. It is sometimes very difficult to make a correct diagnosis.

Some causes can only be identified at autopsy. That is why at the service station, after overhaul, car owners are not told about the identified reasons. It's just not optimal in such cases to do such a repair. The way out of this situation is much easier and much cheaper.

Dripping oil and leaking oil on the engine

Everything is clear here, if it slowly drips or leaks, it can be fixed by replacing gaskets and seals. So you can get rid of the problem: oil leakage from the engine.

The valve cover gasket is located at the top of the engine. If the tightness is broken in this place, then distinct traces of drips can be observed on the side walls. Much will not be able to leak, and tightness can be easily and inexpensively restored. In this way, we get rid of smudges.

Leaks can happen from under the cylinder head gasket. The part may be damaged in various places. There are leaks in the cooling system. Why did oil leak? This can happen due to damage to the gasket in the place between the cylinders and the cooling system itself. From the outside, the walls will be dry, but the coolant will change color and become significantly cloudy. It will foam.

The problem must be urgently resolved as soon as possible, otherwise the motor may fail.

If it flows from the crankshaft and camshaft oil seals, then it is very difficult to see it. However, from below, on the crankcase protection, an oil puddle can be observed, which indicates whether oil has flowed from the engine. The problem is easily fixed.

There may be smudges from the gaskets of the oil pan, but this is not easy to see.

At the entrance to the gearbox is the rear crankshaft oil seal. Basically you can see it only with the box removed. However, it is possible to make a diagnosis. From the side of the box, traces of smudges will be observed - this is dripping oil.

It could also be leaking from the oil filter. This often happens. It's just that the gasket is being replaced, the filter itself is also desirable to be replaced.

May result from incorrectly selected product parameters. Here it is necessary to take into account the viscosity, and all kinds of additives, and the base. Sometimes some oils can be completely incompatible with gum.

If the car has been sitting for more than three weeks, it could drain into the sump. And in the absence of oil, rubber gaskets can dry out or deteriorate, and therefore oil drips.

If the oil from the engine has completely leaked out, then it is urgent to fill it there. Working without oil is death. If it runs in a stream, you need to go to the service station. It is sometimes impossible to make a diagnosis on your own, because there are just a lot of reasons.

Burning engine oil

If blue smoke can be observed from the exhaust pipe, this is a symptom of oil burning. Here, high consumption is easy to diagnose. When normal quality gasoline burns, blue smoke does not form. If black smoke is observed, then this means that the injection is not working as it should. If it regularly burns in huge quantities, a black film will be visible on the edges of the exhaust pipe. These are symptoms that the car is smoking and eating oil.

It is much more difficult to find out for what specific reason it burns. Here it will not be possible to find out the reasons without the autopsy process. Not a single, even the most qualified, car mechanic will be able to clearly say why this is happening. But today there are fairly simple and inexpensive methods to combat oil burning. You can try to apply them before starting the process of opening the motor.

First, you need to know that oil burns in any kind of engine. It cannot fail to burn. Lubricating foam forms everywhere, and cylinder walls are no exception, and this is where the mixture of gasoline and air burns. But that doesn't matter, something else matters. What is the rate of oil for waste in the engine, and how much burns out in fact. One more detail. The volume of the product that will burn out directly depends on the mode of operation of the motor. Here is a direct dependence of the volume of burnt oil on the speed. The laws of physics work here. More revolutions - the motor heats up more, which means it liquefies, which means more oil will burn in the chambers and on the cylinder wall.

But do not prematurely arrange a funeral for the motor. Let's find out how the motor is used, in what modes, as well as its design.

Smokes and eats oil: reasons

A popular cause of oil burning is the poor quality of the combustion product. Most modern motor oils, and especially synthetic formulations, have one of the properties, namely, they reduce losses in the fuel combustion chamber. This is achieved with the help of a special composition of the base and various additives that reduce waste. Here the principle is not complicated. Major volatile compounds must be removed from engine oil. Then, as the temperature rises, the stability will increase. However, if it was cooked in a cellar around the corner, then these properties simply will not exist, and the oil will be consumed and burned in huge quantities.

The next reason that the car smokes and eats oil is the use of worn oil scraper rings on the pistons. Wear processes cannot be avoided. Wear starts at the bottom. Among the first to wear out are those parts that are affected by pressure, which are constantly moving and practically not lubricated. Under this description, those rings that are installed below the compression fit perfectly. Oil scraper rings, so they are poorly lubricated. Their task is not to let him through to the compression rings. They, of course, miss the oil, but dosed.

Wear rings must be replaced. True, often this event entails a major overhaul of the entire engine.

A possible cause of oil burning is coking of the piston rings. Rings can only work properly if they move. If the rings are coked, then it is natural that they completely lose their sealing properties. Therefore, the consumption of the product, and it is usually accompanied by a decrease in the compression level on several cylinders, is quite large. This can be caused by the use of low-quality lubricants. Usually, high-quality engine oil, in addition to directly lubricating properties, also has the ability to flush out combustion products from the engine and cylinders. And cheap products do not have this ability. Sometimes the rings may be in a normal condition. It is treated with disassembly and decoking, but you can do without it. To decoke the rings, you need to use special chemicals.

Another cause of oil burnout is worn cylinders. The larger the product burns, the larger quantities it re-enters the cylinders through the seals. Seals are two units: rings and cylinders. If the working surfaces of the cylinders have significant wear, then the oil waste will be large.

Worn-out cylinders freely pass it, and it burns out there in large quantities.

Whether to change the oil at high consumption

Car enthusiasts often ask themselves the question of the need to replace the product with the problem of increased consumption. You can not change, because the engine receives the same amount of oil that would be without consumption during replacements.

Most motorists when buying a car are interested in the consumption of lubricants. Can the answer to this common question give an unambiguous assessment of the technical condition of the "iron horse"?

It is generally accepted that increased oil consumption in the engine indicates that not everything is in order with the machine. In the case when the flow rate increases sharply, and topping up is carried out on an ongoing basis, it is clear that the cause should be looked for, inspection, diagnostics and repair should be carried out. Usually the car owner is tuned to the standard indicators determined by the manufacturer, but when he looks at the dipstick and sees an overrun, the first thing that comes to mind is the thought of a breakdown and upcoming large investments. In addition, these are additional costs for car maintenance. Periodically checking the lubrication level should be taken as a rule, but let's look at the causes of excessive oil consumption in the engine.

Where does the oil go?

Increased oil consumption in the engine does not always indicate its deplorable state, in addition, its unchanged level also does not indicate the normal state of the engine. All internal combustion engines must consume fuel and lubricants, the question is how much it takes. There are several reasons for different volumes of consumption, but they can be conditionally divided into two groups:

• Established, associated with the design feature of the engine;
• Non-standard, indicating the wear of parts and failures in the settings.

Large-volume internal combustion engines, especially V-shaped ones, are distinguished by increased oil consumption than in small-capacity single-row engines. To prevent dry friction, the autolubricant forms a protective film on the cylinder walls to lubricate the piston rings, and accordingly burns out in new engines. In general, manufacturers of engines and oils strive to provide maximum protection for rubbing surfaces while minimizing waste.

Lubricant inevitably seeps into the combustion chamber as the pistons and valves move. Inevitably, oil is wasted on the intake through the crankcase ventilation system, crankcase gases carry out a small amount of lubricant. Turbocharged engines require lubrication of the turbine parts. The most banal reason for increased waste: if the lubricant did not burn out, then it leaked out, hence the high oil consumption.

In this article, we will not delve into the diagnosis of leaks, the replacement of oil seals and gaskets, but will focus on waste.

Diagnosing Excessive Oil Burnout

The simplest diagnostic technique to assess lubricant waste is a visual assessment of exhaust gases. If car oil enters the exhaust system, then the exhaust at high speeds is a bluish smoke, the combustion of high-quality gasoline does not give such a color to the gases. For comparison, in case of failures in the injection system, black smoke is emitted from the exhaust pipe, these are already symptoms of another disease.

There is another way to detect the constant burning of the suit over a long period: a black oily formation grows on the edges of the exhaust pipe. You can more accurately determine the ingress of oil into the exhaust system by diagnosing using a gas analyzer.

Assess your driving style. The operating mode of the internal combustion engine directly affects the oil consumption in the engine. When working at high speeds, the pressure and temperature of the lubricant increase, when heated, its viscosity decreases, therefore, more lubricant seeps into the working cylinders, which entails increased oil consumption.

Many are mistakenly tied to the consumption rate per thousand kilometers. Operation in the urban cycle is marked by a constant change in speed, frequent starting and stopping of the engine, idle idle, which is different from driving on the highway. Uniform movement at a speed of about 100 km / h in fifth gear and the manner of driving at high speeds with constant overtaking will show different fuel consumption, different waste.

It is much easier to come to the conclusion that the lubricant burns out above the norm than to identify the cause that explains the increased burnout.

The main reasons for engine oil to burn in the engine

1. Wrong oil filled. It is not suitable for your engine. If the suit is too liquid, then its leakage into the combustion chamber is inevitable. Viscous oil will form a thicker film and remain on the inner surface of the cylinders, more "soar" and burn. They cannot boast of properties that reduce volatility, low-quality oil fakes and fakes. I am glad that flushing the engine and changing the oil will help eliminate the first cause. For DVZ with high mileage, it is recommended to change synthetic oil to semi-synthetic, often this helps to reduce consumption. Be sure to follow the recommendations of the car manufacturer.
2. Deterioration of oil seals (or valve seals) due to poor-quality rubber, temperature changes or structural failure due to the use of unsuitable lubricants. Valve seals are inexpensive, and their replacement is not very laborious, but this operation significantly reduces oil waste.
3. Wear of piston rings. The problem is eliminated by replacing them, and this is already a major overhaul. In some cases, decarbonization helps, that is, a short-term engine load at maximum speed, more often such a procedure can remove carbon deposits from the rings if the car has not been used for a long time. There is a wide offer of special auto chemicals on sale, but sellers will not be able to guarantee a positive result of decarbonization, and they will prefer to remain silent about the effect of additives on motor resources.
4. The development of cylinders, namely the wear or damage to their inner surface. In this case, without resorting to an engine overhaul, you can change the oil to a more viscous one and put up with constant topping up, still cheaper than an overhaul. This measure is temporary, and the most correct solution would be to replace the entire engine.
5. Due to the destruction of the inter-valve bridges on the piston, the sealing of the combustion chamber deteriorates, as a result of which the pressure of the crankcase gases is injected, and the oil is carried out of the crankcase through the engine ventilation system through fuel injection.
6. For turbocharged engines, there is another reason: the increased oil consumption in the engine is affected by a malfunction of the turbine, so repair or replace it.

Good luck, driving without breakdowns and smooth roads!

Many motorists, for one reason or another, do not attach much importance to periodic. At the same time, one of the most important conditions for the operation of a car is to control the level of engine oil in the crankcase.

It is important to understand that a critical drop in the oil level and the consequences for the vehicle engine can be catastrophic (increased wear of the rubbing parts of the engine as a result, and complete failure of the internal combustion engine). In this article, we will look at malfunctions that cause a sharp and intense drop in the oil level in the engine crankcase, as well as ways to eliminate them.

Read in this article

Why is oil leaving the engine

So, if the driver regularly monitors the level of lubrication, then it will immediately be noticeable that the oil has left the engine. In this case, oil consumption is usually affected by two factors: engine oil leakage and its burnout.

• Let's start with the most common reasons. For example, it occurs in case of incorrect assembly of the motor and incorrect crimping of the cylinder head. The result is that the head through the gasket is not evenly pressed against the cylinder block, which leads to breakdowns in places where the tightening is loosened. The car owner can determine this malfunction with the naked eye by smudges of engine oil from under the head of the block.

Also, a breakdown of the cylinder head gasket can also be fraught with coolant entering the crankcase. In this case, the appearance will signal this. When removing the dipstick from the crankcase, one can observe an increase in the oil level and a whitish shade (emulsion) that is uncharacteristic of the oil.

In this situation, in no case should the engine be started, in order to avoid the appearance of wear on the crankshaft liners, increased wear of the camshaft cams and scoring on the mirror surface of the cylinder liners.

To solve the problem, it is better to deliver the vehicle by a tow truck to the place of repair and replacement of the cylinder head gasket. It is also a mistake to believe that without replacing the gasket, an additional broach of the block head will give a result. The fact is that since the BC head gasket is already deformed, there will be oil leaks at the places of deformation.

A mandatory measure in this situation is to remove lubrication lines from emulsion residues, after which oil recommended by the engine manufacturer is poured into the engine.

For the information of car owners, motor oils of not expensive brands can be used as flushing oil, but with an appropriate viscosity coefficient. This will not harm the internal combustion engine, since the duration of the engine operation on cheap oil is not significant, the loads are minimal, and the task of such lubrication is to flush the engine from the emulsion. At the same time, the savings of the car owner's budget are obvious.

• Worn crankshaft oil seal (front or rear) is also a fairly common cause of engine oil leakage. This problem can sometimes be easily diagnosed by an oil puddle under a car or drips. However, in some cases, obvious leaks are not always visible without inspecting the lower part of the car.

The crankshaft oil seal is made of rubber, but it is not durable and is subject to various influences (elasticity is lost, wear appears, rubber is subject to mechanical wear by abrasive debris contained in engine oil, etc.). In this situation, the solution to the problem is obvious. The crankshaft seal needs to be replaced. It is also recommended to fill in fresh engine oil and change the oil filter.

• An oil leak is also on the list of possible causes for a low oil level in the crankcase. The problem occurs as a result of incorrect installation of the oil filter (undertightening or constriction, as well as abrasive dust on the filter gasket). A factory defect of the oil filter is still possible (oil may leak in the places where the filter housing is rolled).

The problem is solved by replacing the oil filter. If the filter is not tight, then you need to try tightening it more. By the way, in order to avoid deformation of the rubber gasket of the oil filter, experts recommend lubricating this gasket with oil before installing it.

As a result, the tightness of the gas distribution valve seal is lost and the engine oil flowing through the leaky valve seal flows down the guides and enters the internal combustion engine cylinders. The grease then burns along with the fuel. Engine oil combustion products adversely affect the performance of piston group parts. The problem can be fixed by replacing the valve stem seals.

• The occurrence of oil scraper rings leads to poor removal of the oil film from the inner surface of the cylinder during the piston stroke. As a result, the oil remaining in the combustion chamber actively burns out, forming coke deposits.

Such deposits lead to coking and bedding of the rings. The result of this is a drop in the power of the internal combustion engine and uneven development of the working surface of the cylinders (ellipse), which entails expensive repairs, as well as the need to replace piston rings.

Where does engine oil go: hidden reasons

Let's start with the fact that in addition to the obvious reasons for the increase in lubricant consumption (oil leakage), there are also indirect ones. For example, .

In simple words, a number of malfunctions in the engine cooling system, insufficiently efficient operation of this system can also lead to the so-called "oil burner".

The reason is that an insufficient amount of heat is removed from the engine, the engine, in turn, becomes more “hot”, i.e. its operating temperature is forcibly raised by several degrees and the internal combustion engine operates at the upper temperature limit.

Accordingly, being constantly exposed to extreme temperatures, the oil intensively “burns out”, and waste products clog the oil channels, reducing the efficiency of the entire engine lubrication system.

• Oddly enough, but malfunctions in the engine can also indirectly provoke increased consumption of engine oil. The problem lies in fuel injectors, which, without proper maintenance, eventually begin not to spray the fuel mixture, ensuring uniform ignition in the cylinder, but pour fuel in a jet.

As a result, uneven combustion of fuel and an increase in fuel begin. In turn, increased detonation leads to the appearance of microcracks in pistons and piston rings, as well as cylinders (liners). Due to these defects, oil scraper rings do not effectively remove the oil film from the working walls of the cylinders. It turns out that the oil breaks into the combustion chamber with all the ensuing consequences.

What is the result

Given the above information, it becomes clear that when the first signs of an increase or a clear overrun of engine oil appear, the car owner must take immediate measures to diagnose malfunctions in the lubrication system. This approach often avoids costly repairs.

It is important to understand that an internal combustion engine (gasoline or diesel) is a complex mechanism in which one minor malfunction leads to more serious problems, up to.

Finally, we note that increased engine oil consumption can not always be affected by breakdowns directly related to the ICE lubrication system: oil seal leaks, gasket leaks, questionable quality of engine oils, factory defects in oil filters, unskilled maintenance, etc.

Causes indirectly related to the lubrication system should not be excluded. We are talking about a violation of the temperature regime, as well as problems with the fuel system, which lead to malfunctions in the internal combustion engine itself.

Read also

Engine oil consumption is increased, but the engine does not smoke oil smoke. How to find the cause and determine where the lubricant goes, recommendations.

Should the engine consume oil and what oil consumption is the norm for the motor. Increased lubricant consumption, main causes, frequent malfunctions.

Not so long ago, a familiar semi-oligarch complained about the exorbitant oily appetite of a new toy. Say, he bought Cayenne Biturbo, and he eats two liters of good expensive synthetics per thousand kilometers ...

The toad seems to have won: the semi-oligarch sold his Porsche. But the question remains: where and why does the oil go? And how to choose one that is not spent so zealously?

The main reason for the loss of oil is its waste (details - in the column on the right). It is influenced by the design and condition of the engine, operating mode, air temperature overboard. And, of course, the properties of the oil itself.

None of the parameters directly tells how fast it will fade. But indirectly this is evidenced by two quantities: the volatility of the oil and the flash point. If the first parameter practically does not appear anywhere and it is difficult to find out, then the flash point is indicated in all specifications. At this temperature, vapors ignite from the surface of the oil film when exposed to open fire (in our case, the flame from fuel combustion). It depends on the composition of the oil: the more light fractions it contains, the lower the flash point.

For testing, we took seven oils of different types, but one viscosity group, corresponding to the "forties" according to the SAE classification. Mineral oil "LUKOIL-Standard" 10W-40 has a flash point of 217 °C. It will go as a base one: we will compare others with it. Three semi-synthetics from the 5W-40 group - ZIC A + hydrocracking oil with a flash point of 235 ° C, Castrol Magnatec (232 ° C) and RAVENOL (224 ° C). Synthetics with the highest flash point were represented by our TOTEK-Astra Robot based on polyalphaolefins (PAO), categorized by the manufacturer as Full Synthetic (246 °C), and ester Xenum X1 with a record 247 °C. Well, to find out if those who believe that synthetics burn out less than other oils are right, they took another oil - Neste Oil, also positioned as full synthetics, but with a relatively low flash point - 228 ° C. Viscosity indicators for all oils are close, but the bases are completely different: mineral waters, simple and advanced hydrocracking semi-synthetics, good PAO-based synthetics, and even the most advanced ester-based synthetic oils.

Strictly measured 3 liters of oil are poured into the bench motor, after which - a 30-hour "check-in" at a conditional speed of 120 km / h. The engine is simple, VAZ-21083: for such a run, almost 4000 km at a constant speed is a serious test. After the “arrival”, we drain the oil to the drop according to a strictly defined ritual. It remains to compare the rest.

It is known that the products of oil combustion affect the toxicity of exhaust gases - but is it strong? To determine this, we measure the amount of residual hydrocarbons in the exhaust during the fixed mode tests. Since the fuel is the same, all differences beyond the measurement error can be attributed to the so-called non-fuel SN, generated by the evaporation and combustion of oil in the cylinders.

The result confirms our assumptions: oil with a higher flash point burns less. So, "TOTEK-Astra Robot" showed one of the best results; the Belgian XENUM X1 was also within the measurement error. Indeed, their flash point is over 245 °C. Among all semi-synthetics, the Korean ZIC A + showed the best result in waste with a declared 235 ° C. And the worst result is in an ordinary mineral water with its 217 ° C. The SN measurements also indirectly confirm these results.

You can object: they say, and so it was clear that synthetics are better than all other oils! But no: compare the results of the semi-synthetic ZIC A + and the full synthetics of Neste Oil - the Korean product has them, albeit not much, but better. It is understandable, the motor does not read the stickers on the canisters, the properties of the hydrocarbon liquid poured into the sump are important to it.

So what to look for when choosing oil based on its minimum consumption? The question is especially relevant for engines beaten by life, for which one oil filling from shift to shift is no longer enough. It is also asked by those who like to drive fast and far, as well as the owners of powerful supercharged engines. The easiest way to navigate is the flash point, since it is given on the sites for all oils. The higher the better. As our tests have shown, a figure above 230 °C promises relatively low waste consumption. And if it climbs over 240 ° C, then it’s very good. True, for the entire time of working with oils in the “magpies” group, only two brands could boast of such values: XENUM X1 and TOTEK-Astra Robot.

It should be remembered that the flash point is different for oils of different viscosity groups. Viscosity, of course, is primary, so first we select the required oil according to SAE, and only then, within the selected group, we will refine our choice, looking for the highest flash point.

WHY AND HOW DOES OIL BURN

There is an opinion: all the oil that gets into the cylinder inevitably and irretrievably burns out. Is it so? Not!

The oil is in the cylinders in the form of a film left by the first piston ring. Its average thickness is 10-20 microns, depending on the operating mode, engine wear, oil viscosity and a bunch of other parameters. If we take a typical one and a half liter engine, it is easy to calculate that with an oil film thickness of 10 microns, approximately a cube of oil enters the cylinders in one cycle. Estimate: if it all burned out, then at 3000 rpm per minute ... 1.5 liters of oil would fly into the pipe! This means that not the entire oil film burns out for each cycle, but only a small part of it.

Remember how oil behaves in a pan when you heat it. First, it spreads over a hot surface, then, as it heats up, it begins to boil and stink. And if you splash cold oil immediately on a hot frying pan, you risk burning your face with splashes. Now about the same, but scientifically. When the oil is heated below its boiling point, it evaporates slowly from the heated surface into the atmosphere. When it boils, evaporation increases dramatically. And at very high temperatures, microexplosions throw oil drops from the pan.

In the engine cylinder, everything is the same. According to our estimates, the first regime of oil evaporation should prevail, when it does not reach its volumetric boiling. It would seem that at the enormous temperatures of fuel combustion in the cylinders, the oil should at least sizzle! But the fact of the matter is that it lies with a thin film on the relatively cold surface of the cylinder, cooled by antifreeze, and therefore does not warm up so much. Only when the pedal is pushed to the floor, the surface layers of the oil film begin to boil. Therefore, when driving fast, you have to add oil more often.

WHERE THE OIL GOES

If there are no drops of oil on the pavement under the car, that is, all the seals are intact, it can be argued that the oil is consumed mainly for waste. In turbocharged engines, it is also spent on lubricating the turbochargers, so the total oil loss there is greater. Next - oil leaks through the oil seals. This expense can become the main one if they are completely worn out or completely dry. Some escapes in the form of oil vapor through the crankcase ventilation system.

By the way, in addition to the fact that money is flying away with oil, its high consumption is fraught with other problems. This is an increased rate of contamination of the internal surfaces of the engine, because the oil burns badly and dirty. This is a decrease in the resource of converters that are not able to digest the products of incomplete combustion of heavy oil hydrocarbons. This is an increase in the toxicity of exhaust gases: it is not without reason that now the "ce-ash" in them is divided into fuel and non-fuel, that is, oil.

ABOUT OIL EVAPORATION

The evaporation rate of the oil should depend on its initial boiling point, fractional composition and the thickness of the oil film formed by the first piston ring on the cylinder wall, which, in turn, depends on the high temperature viscosity of the oil. All this is good, but descriptions of oils usually do not contain such parameters. There is, however, the so-called oil volatility according to NOACK - the lower it is, the less the oil's tendency to waste. The principle of determining this parameter is simple: the oil is heated for one hour at a temperature of 250 °C, after which the weight loss is estimated. Minerals with this torture lose up to 22-25%, good modern synthetics - less than 8-10%. The higher the class of the base oil, the lower the loss of oil for volatility. Unfortunately, most companies do not indicate this parameter in the descriptions of their oils.

In a real engine, everything is much more complicated. There, at sharply variable temperatures and pressures, a thin film of oil evaporates, which cannot be measured by any model installation. Hence the possible errors: it follows from the method that the volatility of more viscous oils is lower, and in practice, with an increase in the viscosity of the oil, its consumption increases. The reason is simple: the thickness of the oil layer on the cylinder walls, and hence its passage into the heating and evaporation zone, increases sharply with increasing viscosity.

THE HIGHER THE CLAIMED FLASH POINT, THE LESS THE BURN OFF.