Engine diagnostics based on exhaust gases and how to reduce gas toxicity on your own. Black, gray, white: What does the color of the exhaust gases mean? Malfunction by the color of the exhaust gases

Currently, there are many different devices, the purpose of which is to assist in engine diagnostics. Some of them work with the engine control unit, allowing you to use self-diagnosis and control of actuators, i.e. fault scanners. Others transmit information about the operation of ignition systems and various sensors. Naturally, an oscilloscope helps most with this. Using various vacuum gauges and compression gauges, we can obtain information about mechanical condition, i.e., about the compression and tightness of the supra-piston space. We can even evaluate the condition of the inner surface of the cylinders using an endoscope. However, the only device with which we can evaluate how the fuel combustion process itself proceeds is a gas analyzer.

There are a lot of different tabular data and instructions like: “If CH is greater than X percent, you should look here, here and there.” No doubt, this is very useful data, and in many cases it really helps. Yes, and know the specific numbers for specific car, one way or another, it is necessary, in any case, it is useful to know that for such and such a car, with a working engine and ignition and fuel supply systems, the CH content in the exhaust should not be higher than Y percent. It’s a completely different matter to know what these numbers mean and where they come from.

There is an opinion, and we support it, that conducting competent diagnostics is impossible without knowing how the engine actually works. This is much more important than the ability to work with repair equipment. After all, no device will ever tell you: “The blue-green wire is broken three centimeters from the ignition switch.” This example is given in order to show: any diagnostic device, not quite scientifically speaking, only gives a hint as to where the malfunction may be hidden. The diagnostician’s job is to correctly use this hint and find the cause. And then eliminate it. Well, it’s not so difficult anymore - fixing a problem is usually much easier than finding it. Why such a long introduction? Moreover, this article will consider issues that are more theoretical than practical.

Leak test

So, gas analysis. Before moving on to the actual story about CO and CH, it is worth recalling: any, even the most advanced gas analyzer will not display the real content of gases in the exhaust if the tightness of the exhaust tract is broken. That is, it will provide incorrect information. It would seem that if the pressure in the exhaust pipe is higher than atmospheric, how can air get there? To answer this question, we must remember that they come out of the cylinders not in a continuous flow, but cyclically: between the moments when the Exhaust valve and gases leave the cylinder, there are moments when the exhaust valve is closed and the gases move through the pipe, so to speak, by inertia. At these moments they create a vacuum in the pipe. The result is precisely the suction of atmospheric air.

The result is confusing readings and unnecessary headache diagnostician Therefore, we repeat, before carrying out the test it is always necessary to check the exhaust tract for leaks. There are two ways to do this. The first one is more innovative. As you know, there are special smoke generators similar to those used during performances by singers and artists. The point is that when the movement they create dense smoke All leaks along the highway immediately become visible. According to Ryazanov, many of those with whom he had to communicate want to use such a device in their work. Despite this, almost no one uses it.

It's hard to say why. Most likely it's a matter of price. Liquid for creating smoke is quite expensive. Therefore, the second method, which is quite old enough to be called “old-fashioned,” is used almost everywhere. Despite this, it has not lost efficiency and is unlikely to lose it until the exhaust system is made radically different. The meaning is banal to the point of triviality: one person clamps the exit hole with something exhaust pipe. Thus, the pressure in it increases. Another person simply runs his hand next to the exhaust pipe, along its entire length. If your hand feels air movement, it is very likely that there is a leak in this place. The second method, despite its archaic nature, certainly wins in the “Efficiency / Price” ratio.

What's the output

After making sure that the exhaust tract is tight, we connect the gas analyzer. The engine is started, the exhaust gases come out, and the gas analyzer diligently, forgive the tautology, analyzes them, showing various numbers. What is what? Let's start from afar. When gasoline is burned, if you look in a chemistry textbook (and combustion is nothing more than a chemical reaction), H20 and CO2 are produced. Unfortunately, this only happens with complete, ideal combustion of the mixture. There are no ideal processes in life. In engines internal combustion This unfortunate fact is further reinforced by the fact that we are dealing with a dynamic process.
During the combustion process, volume changes (because the piston moves), temperature, pressure, and even the thermal conductivity of the medium itself. It is very, very difficult to calculate the combustion process of the mixture in the combustion chamber. We owe all this to the content of all sorts of foreign substances in the exhaust. The best known of these are the good old CO and CH. What are they? CH is a general designation for all hydrocarbons that are obtained from unburned gasoline (namely all, and not any specific one, as some auto repair specialists believe). That is, we repeat, CH is simply unburned gasoline. CO is gasoline that started to burn, but for some reason it was not lucky enough to find another oxygen molecule in order to burn out (that is, oxidize) to CO2. For a better understanding, Ryazanov gives an analogy with a fire:

	This is what the composition looks like exhaust gases serviceable with normal mixture formation. As you can see, the parameter values are within normal limits, but not standard.
	Here we see increased CH content. The most common cause of this is misfire. In addition to CH, an increased oxygen content is also noticeable. Oxygen enters the exhaust gases from the combustion chamber along with unburned gasoline
	In this case, there are leaks in the connections. At the same time, atmospheric air is sucked in. As a result, the oxygen content increases significantly, but the amount of other gases remains almost the same, because their content in the atmospheric air is small. Along with the increased amount of oxygen, the gas analyzer also shows an increased calculated lambda coefficient.
	Composition of exhaust gases from an engine that complies with Euro-2 standards. You can immediately feel the influence of the catalyst, which regularly burns the exhaust gases. The CO content is below the measurement limit of the gas analyzer used. CH is also very small. A high CO2 content coupled with a low oxygen content also indicates good fuel combustion. And the “lambda” parameter, accordingly, is almost equal to 1.

Once upon a time, when injectors were mostly thought of, and used almost everywhere, gas analyzers were a good match. With what could be obtained from carburetor mixture formation, these two parameters were quite sufficient for both diagnostics and adjustment of the fuel supply system. Now things have become more complicated. First, environmental regulations have become stricter.

Secondly, injection systems allow for more precise mixture formation. But to take advantage of this precise mixture formation, the two above-mentioned parameters are not enough. Therefore, other gases must now be taken into account. Which? Firstly, CO2 content is now taken into account. This is a product of complete combustion of gasoline, and it is also important. In addition, the exhaust contains oxygen and various nitrogen oxides. Where do nitrogen oxides come from? The answer is logical: they are taken from the air, because the air contains about 80% of nitrogen. And at temperatures of about 1000 °C, nitrogen quite readily begins to react with oxygen, that is, to burn.
Since a temperature of 1000 °C is not something extraordinary for a combustion chamber, the appearance of nitrogen oxides is natural and even expected. From the above, by the way, it is worth concluding that using a two-component gas analyzer is similar to hanging a sign above the entrance: “We are not professionals.” At a minimum, a four-component device is required. Quadruple gas analyzers measure the content of CO, CH, NOx, CO2.
Five-component gas analyzers also measure the amount of oxygen. The use of a five-component gas analyzer is still preferable. However, when choosing “there is no gas analyzer at all or there is a two-component one,” you should certainly give preference to the second option.
I would also like to distract myself with important nuance. If the first four parameters are measured using infrared cameras, then the oxygen sensor (for measuring the amount of oxygen) works on a different principle. Therefore, it has a certain service life and must be replaced periodically. In addition, since the air contains a decent amount of oxygen, this sensor begins to work from the moment it comes into contact with the atmosphere. Two facts follow from this: firstly, regardless of whether you used a gas analyzer or not, this does not affect the frequency of replacing the oxygen sensor; secondly, when purchasing an oxygen sensor, you need to check the tightness of the packaging. If it is leaky, then the service life of this sensor will be reduced by exactly the same number of days as have passed since the seal of the package was broken. And it is unlikely that it will be possible to establish when this happened.

CH, as mentioned, is unburned fuel. If this parameter is too high, which means that gasoline does not burn completely. This is possible in two cases:

1)rich mixture. Everything is simple here. There's a lot of gasoline. There is little air. And not every molecule of gasoline contains an oxygen molecule. The fuel would like to burn, but there is not enough oxygen. So gasoline is literally thrown out into the pipe;

2)lean mixture. Yes, it sounds paradoxical. It would seem that there is enough oxygen and not a single molecule of gasoline will leave offended. However, this does not happen, and the gasoline does not burn.

How can we tell if our mixture is lean or rich? This is where knowledge of the second parameter comes to the rescue. As already mentioned, CO is the gasoline that started to burn, but something prevented it from doing so. But the lack of oxygen prevented him from doing this. In the case of poor mixtures, we have an abundance of oxygen, and if a gasoline molecule bumps into an oxygen molecule, then a second oxygen molecule is probably somewhere nearby. Therefore, if a gasoline molecule begins to burn (i.e., oxidize), it will certainly oxidize. Thus, with lean mixtures the CO content approaches zero. In the case of a rich mixture, there is not enough oxygen for anyone. Therefore, along with increased CH, there will also be increased CO.
Unfortunately, even with an ideal mixture composition, ideal combustion will not be achieved and actual fuel will begin to go into the chimney, from which it is still possible to obtain useful work. It is burned in the catalyst (if available). We don’t get mechanical energy from this, but at least we don’t spoil the environment.
As you can see, already knowing only two parameters, you can draw some conclusions about how the engine works.

Gas analysis to the rescue

However, the possibilities of gas analysis are by no means exhausted here, but rather are just beginning. Let us take for consideration a malfunction such as misfire. Misfires are fundamentally divided into two cases: misfires, when for some reason there is no spark, and a violation of the formation of the mixture charge, when there is a spark, but the fuel does not burn. One of the reasons for disturbances in the formation of a mixture charge is incorrect operation of the injectors. That is, the nozzle does not spray fuel in an even spray, but simply supplies gasoline in a large drop.
As you know, gasoline itself does not burn, but its vapors burn when mixed with air. Therefore, if we have a drop of pure gasoline surrounded by pure air, it will not ignite. One way or another, if we are faced with a misfire problem, there are options. The simplest case is when the engine is tripping, that is, one cylinder simply does not work. The decision here is quite simple: check the spark, check whether fuel is supplied. All in all, standard set procedures.
It is much worse when omissions occur chaotically. Now the first cylinder has not fired, then the second, etc. That is, there is clearly no one idle cylinder, which can be clearly defined. With such a problem, an unpleasant effect appears: vibrations of the engine and the car as a whole.

It should be noted that vibrations can be caused not only by misfires. For example, the reason for this may simply be a broken belt driving the balance shaft, or simply broken engine mounting pads.
This is where a gas analyzer is practically indispensable, because it saves a lot of time and labor on testing a hypothesis. If everything is normal with ignition, then the exhaust composition will be normal. If misfires are present, this will clearly appear on the readings.
Firstly, if the fuel does not burn, it simply goes into the exhaust. This is already a sharp increase in CH. In addition, during normal combustion of the mixture, CO2 is also released. The CO2 content in the air is low; if the mixture does not burn, then the air also goes into the exhaust. Therefore, the CO2 content in the exhaust will be reduced. In addition, the air going into the exhaust sharply increases the amount of oxygen. This method, naturally, will not tell whether the problem is in ignition or in the formation of the mixture.
But it’s a sin to complain here. Connecting a motor tester and checking the operation of the ignition system is unlikely to be a problem for a knowledgeable person. And it’s much easier to search when you know what exactly you’re looking for. Moving from the specific to the general, gas analysis allows us to determine a certain general line for troubleshooting.
As an example, we can cite a very common customer complaint about high consumption fuel. It’s worth noting here that first of all you should ask the owner about his driving style. True, as the experience of a large number of diagnosticians shows, the overwhelming majority of clients say that they drive calmly. Unfortunately, the concept calm ride everyone has their own. Therefore, after questioning the client, it is necessary to trust impartial instruments. Or rather, first to one impartial device, the benefits of which we are talking about in this article.
Most likely cause high flow rate is naturally a rich mixture. But we should not forget that a lean mixture can cause the same problem. Why this happens has been said above, but we will repeat it. With a lean mixture, incomplete combustion of fuel still occurs. In this case, the engine does not develop the required power, and the driver’s instinctive action is to press the gas pedal harder. It turns out that the fuel not only does not burn, but the amount of this unburned fuel increases as a result of attempts to apply gas.

How to reduce the toxicity of exhaust gases on your own and undergo maintenance

In 80% of the toxicity of exhaust gases is influenced by several main factors:
1. Fuel (first and main factor)
2. Engine condition (wear, amount of dirt)
3. (type, quality, purity)
4. Condition (resistance)

Let's look at each of the factors.

1. Fuel. Before you go to technical inspection, a few days before, should only be filled high quality gasoline with high octane number. This approach will dramatically reduce the content of toxins in exhaust gases.

2. Engine condition. This is the most common factor that leads to changes in the composition of the exhaust. It is recommended to clean the fuel system twice a year and do not forget to periodically change fuel filter. The condition of the spark plugs greatly affects toxicity; it is recommended to replace them before maintenance.

3. Motor oil. Oddly enough, the quality motor oil also changes the composition of exhaust gases. Synthetic motor oil leads to a decrease in toxicity, while mineral oil leads to an increase. Therefore, before undergoing maintenance, it is recommended to replace the old engine oil with fresh one; you should only use quality oil, purchased from official representatives.

4. Condition air filter. Everyone knows that air filter resistance (contamination) causes a decrease in power, excessive vacuum in the intake manifold and increased toxicity. Before undergoing maintenance, it should also be replaced with a new one!

Many experienced drivers They know that some car malfunctions can be diagnosed by the color of the exhaust gases. If the exhaust pipe begins to emit smoke while the engine is running various colors- from white to black, this a clear sign presence of malfunctions in the vehicle.

Photo: JT (flickr.com/photos/environmentblog/)

And here the main thing is to promptly respond to warning signs, identify and eliminate possible malfunctions or breakdown to avoid major and costly repairs.

Today we will try to understand what types of malfunctions can be diagnosed by the color of the exhaust gases using the example of an injection and carburete gasoline engine.

But before moving on to considering malfunctions, it is necessary to talk about some general points.

First of all, it is worth noting that when the car is started in cold weather, white smoke is absolutely normal, provided that it disappears when the engine warms up thoroughly. The cause of the whitish haze is steam generated from the combustion of condensate formed in the vehicle's fuel system.

Also, barely noticeable white smoke coming out of the exhaust pipe in cold weather is not a malfunction. However, in severe frost this smoke may be quite noticeable, but this is also a completely normal phenomenon, just like steam from the mouth when exhaling warm air.

It is important to be able to distinguish steam from white smoke. This is quite easy to do; the steam is translucent and quickly dissipates after leaving the pipe. The smoke is denser and stretches in a trail, quickly dissipating only in the presence of wind.

But smoke from the exhaust pipe can be not only white. It can also be black, bluish, or gray.

The color of the smoke varies depending on the quality fuel mixture(usually over-enrichment with fuel), as well as from what was mixed into the fuel mixture during engine operation. And this could be engine oil or coolant. These impurities do not burn completely in the cylinders and color the exhaust in different colors.

Obviously, the fuel supply mechanism is responsible for poor preparation of the fuel mixture. And the ingress of foreign liquids into the cylinders indicates excessive wear of individual parts of the piston group.

But not everything is so simple. For example, the situation may develop according to the following scenario: the engine cooling system has broken down, which begins to periodically overheat. This results in burning piston rings, which begin to leak oil into the cylinder and smoke appears from the exhaust pipe.

You can replace the rings, the smoke will stop for a while, but if the root cause is not eliminated, bad job cooling system, then after a while the malfunction will make itself felt again, smoke will appear again.

That is, smoke from the exhaust pipe most often indicates that there is serious problems with the engine, namely with the fuel supply or cooling system, but in order to accurately determine what the root cause is, you will have to analyze and compare all the available facts.

As an example, let's look at a few possible situations...

Injection engine

About the presence of malfunctions or breakdowns in the engine injection type equipped with an injection system, the vehicle's exhaust system signals the output of black, blue or white exhaust.

Black exhaust

In engines of this type, as in carburetor analogues, black exhaust gases may be formed and discharged. Often this problem occurs due to the fuel mixture being supplied too rich.

Such a malfunction occurs due to the breakdown of any sensor or failure of the control unit of the fuel supply system. In this case, you will only need to simply replace the sensor (if it turns out to be faulty) or replace the entire control unit (a more complex and expensive operation).

Additional reasons for the appearance of black exhaust may be the needle hanging in the nozzle on the intake system, the constant supply of low voltage to the working injector, or the appearance possible problems in the operation of the control unit (for example, changing pulse transmission frequencies).

White or blue (gray) exhaust

Often white or bluish exhaust appears due to water getting into the fuel or an oil mixture into the combustion chamber. For internal combustion engines equipped with a turbocharging system, the appearance of white or bluish exhaust gases is often caused by breakdowns of the main boost turbine.

Carburetor engine

In a carburetor-type engine, the appearance of malfunctions is manifested by the output of exhaust gases, which also have a white, gray and black color.

White exhaust

As is the case with injection engines, in an internal combustion engine of this type, white exhaust indicates the presence of water in the fuel. The reasons for the appearance of water in fuel tank quite a lot - the formation of condensation in the tank and in the pipelines; high humidity air when refueling; water ingress from the cooling system.

Other reasons for the appearance of white exhaust include a decrease in the tightness of the head gasket, the ingress of coolant into the fuel cylinders, and water leakage from the system, which is responsible for heating the carburetor.

In some cases, thick white smoke appears due to poor engine warming up to the desired temperature, which may result in some water remaining in the exhaust system (this is why short trips are very harmful for the car, especially in cold weather).

Blue exhaust

Exhaust blue or of blue color appears as a result of some oil entering the combustion chamber. This can often be due to wear on the cylinders and pistons of the internal combustion engine fuel system.

The degree of wear of parts is determined by measuring the compression level. If the compression level corresponds to the set values, therefore, valve seals - bushings and cuffs - are responsible for the formation of a bluish exhaust.

Often, blue exhaust appears due to the occurrence, breakage or wear of oil scraper piston rings.

The most likely reasons for the release of bluish exhaust gases also include a decrease in the elasticity of the cuffs and rings in the bushings and valve plates; high degree of wear of valve seats and main parts of cylinders and pistons; high oil level in the crankcase; as well as the use of fuel Low quality with oil impurities.

Black exhaust

Black exhaust carburetor engines is formed as a result of insufficient combustion of the fuel mixture with the formation of thick soot. The main reason for this phenomenon is the supply of too rich a fuel mixture to the carburetor.

TO additional reasons removal of black exhaust gases from exhaust system can be attributed high level fuel in a float-type chamber; poorly opened air supply damper; presence of blockages in the nozzle; worn out jet holes; use of jets of inappropriate sizes and types; idle air valve failure; malfunction of the spark plugs.

Of course, these are just a few probable reasons why smoke may appear from the exhaust pipe, but the main thing is that now you know in which direction you need to dig to get to the bottom of the true cause of the malfunction.

Analysis of the color of diesel engine exhaust gases is one of the control methods normal operation power unit. By the color of diesel exhaust, you can accurately assess the condition of the engine, localize faults in engine systems and structural components, identify wear, malfunctions of diesel injectors, etc.

Smoke diesel engine is a product of combustion of the working mixture in the form of gas. Optimally configured with working systems, it does not smoke after warming up; emissions into the atmosphere are visually noticeable only in the cold season and represent white water vapor. A change in the color of diesel engine exhaust gases indicates a number of specific malfunctions. In different cases, diesel exhaust often occurs:

white (with a shade of gray);
grayish (grayish-blue);
thick black (smoke with soot);

Read in this article

Diesel smokes white exhaust

Fuel injection diesel unit means supplying fuel to the cylinders under high pressure through a diesel injector. As diesel fuel passes through the nozzle, a so-called spray pattern is formed, due to which the supplied fuel is evenly divided into small drops in the diesel cylinder. Next, the sprayed fuel particles inside the cylinder are heated, and their active evaporation begins.

A fully serviceable four-stroke diesel engine in any operating mode (at Idling or under load) of the unit receives an effectively atomized portion of fuel at a clearly defined moment after the compression stroke in the engine cylinder. Next, the mixture self-ignites due to heating. Afterwards, the fuel-air working mixture of diesel fuel and air burns completely, giving maximum useful energy to the piston. The result is the release of exhaust gases from the cylinder. White smoke from a diesel engine pipe occurs for the following reasons:

increased humidity in the exhaust system during warm-up;
fuel may not burn completely in diesel cylinders;
coolant entering the internal combustion engine cylinders;

Condensation in the exhaust system

For the warm-up mode of a cold engine, white exhaust from a working diesel engine is normal. In fact, White color produces water vapor in the vehicle exhaust system. Water condenses from the air after the machine is idle. After starting the engine, part of the condensate flows out in the form of water droplets and collects at the end of the exhaust pipe, while the other part of the water begins to evaporate. After heating the exhaust system of a diesel or gasoline engine water and condensing steam usually disappear. The exception is winter period. The lower the temperature outside, the longer and more intense the vaporization occurs. The reason is that the exhaust system heats up noticeably slower in cold weather.

Diesel does not burn completely

Also, white exhaust during warming up of the diesel engine occurs due to untimely self-ignition of the working mixture in the cylinder. The whitish-gray color of the exhaust indicates the presence of gases that should have pushed the piston in the cylinder, but ended up in the exhaust.

Note that this phenomenon is characteristic of both a serviceable diesel engine during the warm-up process in winter and a faulty diesel engine. In the first case, diesel fuel enters the cylinder and evaporates, but complete combustion of the mixture does not occur, taking into account the fixed angle of fuel supply. This is caused by insufficient temperature inside the cylinder for timely ignition, which immediately goes away with the heating of the internal combustion engine and is not a malfunction.

The appearance of white exhaust with a grayish tint on a fully warmed-up diesel engine indicates deviations from the norm. The reason is the same delay in self-ignition of the fuel in the combustion chamber as a result of an impaired fuel supply angle, but this occurs after the engine has reached operating temperature.

If diesel smokes white, this indicates that diesel injectors They normally serve and spray diesel fuel. Flash delay leads to a decrease in the temperature in the cylinder, the speed and uniformity of combustion of the mixture decreases, regardless of the efficiency of fuel atomization by the nozzle. In this case, the white color of the diesel engine exhaust indicates:

problems with glow plugs;
compression drop in cylinders;
wear of injection pump plunger pairs;
increased injection pressure of injectors;

With such malfunctions, the diesel engine begins to experience difficulties with power; the diesel engine may stall and operate unstably. idle speed and under load. The power unit loses power, acceleration dynamics decrease, fuel consumption increases noticeably, and the internal combustion engine’s response to pressing the gas pedal becomes less clear.

Coolant in cylinders

The presence of very thick white smoke in the exhaust of a heated diesel engine can be caused by coolant entering the engine cylinders from. The color of the exhaust may change, since the presence of antifreeze or antifreeze in the combustion chamber causes the diesel engine to smoke white, grayish or white-blue smoke. This depends on the components that make up the coolant in the cooling system. The density of the smoke is also affected outside temperature air (at negative values, the exhaust becomes thicker).

The main cause of diesel smoke in this case is the water contained in the coolant. It actively evaporates from contact with heated components. The result is copious amounts of fog from the exhaust pipe. This malfunction is especially dangerous for diesel engines compared to petrol car. The sulfur content in diesel fuel is increased, the temperature in the cylinder is high, and the ingress of water from the coolant leads to the active formation of sulfur oxide. The presence of sulfur dioxide has a detrimental effect on the service life of the diesel engine and associated systems.

Coolant will enter the cylinders as a result of the fact that the gasket may be punctured, deformed or burnt out. Also common cause there is a crack in or in the cylinder block itself. Liquid may penetrate into internal combustion engine cylinder also through the intake system. This is caused by a leaky gasket. intake manifold, if on a particular motor this is structurally possible.

Additionally, liquid penetration into the cylinders can be diagnosed by monitoring the condition of the cooling system, checking the coolant level, as well as by the presence of exhaust gases (gas plugs) in the engine cooling system. To do this, simply unscrew the radiator cap or expansion tank. The smell of exhaust gases and/or an oil film on the surface of the coolant will indicate the diagnosis. When liquid enters the cylinders, the level will naturally decrease. If cold engine start, without tightening the expansion tank plugs, then the pressure in the cooling system will increase, the coolant level will increase expansion tank will rise, but will be unstable. Gas bubbles will also appear in the tank, coolant may spray out of filler neck tank.

If the engine is turned off, liquid from the cooling system will begin to enter the cylinder, pass through the piston rings and end up in. This is how antifreeze gets into the engine oil pan. Gradually the oil will mix with the coolant. The result will be the appearance of an emulsion. The engine oil itself becomes visually lighter and loses its luster upon contact with the liquid. Beneficial features oils are lost. Penetration of the emulsion into the lubrication system will cause the appearance of a characteristic light brownish-yellow foam. This foam will be deposited on the valve cover and oil filler plug.

Small microcracks mean that there may be no signs of gases and oil entering the cooling system. The amount of coolant in the engine oil with such damage is not large, the oil may look clean, the process of foaming under the plug valve cover is present, but it is not intense.

More serious damage leads to active accumulation of coolant in the space above the piston, which makes it difficult engine start(heavy rotation of the crankshaft by the starter). Excessive coolant leaks into the cylinder can lead to water hammer, bent connecting rods and major repairs.

It should be added that such problems are often associated with previous overheating of the diesel engine. In parallel with eliminating the main problem, the cooling system may also require a thorough inspection. It is necessary to ensure the functionality of the thermostat, radiator, radiator and expansion tank caps, cooling fan, serviceability of the fan switch sensor, integrity of the pipes and reliability of connections.

Conclusion

The presence of white smoke, with the exception of cold condensation, in the exhaust of a diesel engine indicates a malfunction of the engine. In the last described case, the need for urgent repairs is obvious. diesel internal combustion engine. If you notice signs of coolant getting into the cylinders or other symptoms described above, then further operation faulty engine is strictly prohibited. The problem can quickly worsen due to the fact that the emulsion in the oil significantly increases wear on both cylinders. piston group(CPG), as well as other systems and components of a diesel or gasoline engine.

White smoke

If your car leaves a lot of white smoke behind, it is likely that the cylinder head gasket or even the head itself is damaged. The exhaust is white because coolant is leaking into the cylinders through a crack in the head/gasket. To verify this, it is not enough to simply check the fluid level in the tank. The defect is confirmed using a test plug, which allows you to determine the tightness of the system and the appearance of overpressure in the system while driving. Only such tests guarantee diagnostic accuracy.

Black smoke

Black smoke primarily affects vehicles with diesel engine and indicates incomplete combustion of fuel. If this is accompanied by a drop in power, then the problem is probably faulty injectors, which, instead of giving a small dose of fuel, pour too much and with the wrong pressure. In this case, you will need to either repair the injectors or replace them with new ones. Repairs, depending on the car, will require from several hundred to several thousand dollars. Black smoke can also be the result of unprofessional chip tuning or a clogged air filter.

Blue smoke

Blue smoke indicates an excess amount of engine oil is being burned. The source of this phenomenon, as a rule, is the turbocharger (drives oil into the intake manifold). But at the same time blue exhaust may be caused by worn piston rings. And if, through for a short time If the exhaust becomes normal again, then most likely it is the valve guides or their seals. Elimination of such defects often requires a comprehensive repair of the turbocharger (about $300) or overhaul cylinder-piston group. Depending on the car, the cost of such services reaches several thousand dollars.

Car owners know that sometimes their favorite vehicle suddenly starts to behave “wrong”. One of the symptoms that is detectable with the naked eye and may bother a sensitive owner is smoke from the exhaust pipe. This article, of course, is not intended to be a comprehensive guide to troubleshooting, but it can give at least some idea of where to start worrying.

Smoke from the exhaust pipe can be divided into white, blue and black. To produce smoke of other colors, you will need not an internal combustion engine, but some other unit.

White smoke is not actually smoke, but water vapor. When fuel burns in an engine, a certain amount of water vapor is always formed, which partially condenses in an unheated exhaust system and becomes visible. How colder car, the more dense the steam turns out. This is a completely normal phenomenon: who hasn’t seen how cars are shrouded in a whitish cloud in winter?

An alarming symptom is visible white steam coming from the car pipe when warm weather and a well warmed up engine. This may be due to coolant getting into the combustion chambers. Sometimes such steam becomes bluish in color and resembles “oily” smoke. However, unlike it, steam quickly dissipates in the air. You can make sure that it is steam by placing a sheet of white paper on the pipe: any moisture that gets on the paper will gradually dry out without leaving an oily residue.

Coolant can enter the fuel combustion zone in different ways: through the head gasket, through microcracks in the cylinder block, and others. The same way in reverse side exhaust gases enter the cooling system. All this is reflected in the coolant: its level in the expansion tank is low, and when the engine is running, gas bubbles can be seen floating in the tank.

In case of some malfunctions, for example, if liquid enters the cylinders due to a leak in the intake manifold gasket, gases are not formed in the expansion tank. However, in any case, the coolant enters the oil and gradually turns it into an emulsion, which, of course, does not improve its lubricating properties.

All of the above means that it’s time to show the car to repair specialists. The described defects quickly progress as the vehicle is used, deteriorating the properties of the oil, which in turn leads to destruction various nodes engine and ultimately to its failure.

The black color of the exhaust occurs when soot particles appear in large quantities, which in turn are formed due to incomplete combustion of fuel in the engine. Such smoke is especially clearly visible against a light background (try to ensure that this background is not the snow-white side of your neighbor’s SUV).

Incomplete combustion is a consequence of oversaturation of the air-fuel mixture. This may be confirmed by symptoms such as increased consumption fuel, unstable engine operation, loss of power.

This can happen for different reasons in different engine designs. In carburetor engines, this may be a malfunction of the needle valve or air jets. In engines with electronic injection - incorrect operation of fuel system control sensors or leaking injectors. In diesel engines - pump defects high pressure or incorrect fuel injection settings.

A common cause of over-richness of the mixture may be a decrease in engine compression. In this case, it does not enter the mixture sufficient quantity air, which means the specific amount of fuel increases, which leads to the fact that part of it does not burn in the engine cylinders.

Pollution environment and fuel consumption are not the only consequences of incomplete combustion of fuel. This has an extremely negative impact on the condition of the engine oil. It is saturated with soot particles, which, spreading through the lubrication channels, actively pollute the engine and oil filters, which leads to disruption of heat exchange. And this, in turn, is fraught with burnout of pistons or valves, and therefore much more serious repairs. How faster car with a black smoky tail will head for repair shops, the cheaper the owner will get off.

Finally, blue smoke, in the entire spectrum of shades from gray to pale blue, indicates that not only fuel is burning in the engine cylinders, but also the oil penetrating there. The same simple test with a sheet of paper near the exhaust pipe can confirm your guess: this time oil stains will appear on it.

The causes of oil leaks into the fuel combustion chamber are mainly related to wear of parts: changes in the shape of the cylinder liner, damage to the piston rings, increased gaps between the valve stems and guide bushings, and so on. It is better to entrust it to a specialist to figure out what exactly needs to be repaired. It is only important to pay attention to the smoke that appears in time.

If not large wear Smoke can only appear when starting a cold engine. With subsequent heating, the parts expand and the gaps return to normal and the engine runs normally. With great wear, the opposite happens; as it warms up, the smoke becomes denser. This is explained by the fact that hot oil has a lower viscosity and more easily penetrates through “abnormal” gaps, which can no longer return to normal only due to the expansion of the metal.

In all the cases described above, the car can continue to move for some time, the duration of which depends on the nature of the malfunction and many other conditions. This period can be extended by treating the engine with agents that restore the surface layer of parts under friction conditions, primarily in the cylinder-piston group. Products such as geomodifiers help protect the oil from fuel, coolant or soot particles getting into it. In addition, the restored surface is able to retain a denser oil layer, which to some extent compensates for the decrease in oil performance properties. And this, in turn, protects other components and mechanisms from damage.

Such remedies are not a panacea and cannot replace the repair of a malfunction leading to smoke from the exhaust pipe, but they can help avoid more significant troubles.

As you plow the roads, don’t forget to look behind you to see what color the trail is following your miracle bird!