Agree, we rarely pay attention to the smoke from the exhaust pipe, because, in fact, the pipe is needed for that in order to remove exhaust gases. However, the situation changes radically when, instead of the usual light steam, dense thick smoke appears, which persists or even intensifies after warming up. And if the exhaust has a pronounced characteristic color, this is a clear signal of a malfunction of one of the engine systems. Which one - we will analyze in this article.
What should be the normal output?
So, let's focus on the color of the exhaust. What should it ideally be? The main rule for determining the "normality" of smoke from the exhaust pipe is its invisibility. That is, relatively speaking, as long as he does not bother you, everything is in order. But as soon as the exhaust loses its transparency, and a whole smoke (and often poisonous) plume literally stretches behind the car, it becomes hard not to notice.
However, there is no need to panic ahead of time. Far from always “colored” smoke from the exhaust pipe means serious damage and costly repairs. It is likely that a small malfunction or wear of a consumable part of the engine system is to blame, and it will be enough just to replace the spare part.
Consider the main causes of smoke from the exhaust pipe: what the color of the exhaust indicates and what actions should be taken.
White smoke from the exhaust
What it looks like: thick white steam when the engine is hot.
White-gray water vapor in cold air after overnight parking is quite normal, indicating sufficient moisture in the exhaust system. It dissipates easily and quickly, and when the engine heats up, it completely disappears. Another thing is if the exhaust literally “hangs” in the air, turning into a thick cloud, and remains even after full warm-up.
Cause: coolant has entered the engine cylinders: most likely damaged cylinder head gasket or a microcrack has formed in the cylinder head or block.
Clue: noticeable antifreeze leak.
Actions: check the coolant level and contact the service - the ingress of gases into the cooling system is fraught with engine overheating and subsequent overhaul.
Important: before proceeding, make sure that it is water vapor coming out of the pipe, and not smoke mixed with oil. To do this, bring a sheet of paper to the pipe and wait a bit: the moisture will evaporate without a trace, and the smoke will leave oil stains.
Blue smoke from the exhaust
What it looks like: oil gray-blue exhaust.
Depending on the degree of illumination and weather conditions the exhaust can change shade from light blue to deep bluish. In any case, heavy blue smoke from the exhaust pipe usually indicates the presence of oil in the cylinders.
Cause: Oil can get into the engine for various reasons:
- banal engine wear, when piston rings lose their seal and compression deteriorates, and oil is consumed more;
- "Occurrence" of rings (coking, loss of mobility) due to Low quality oil and fuel or rare car operation and concomitant overheating;
- violations in the crankcase ventilation system due to excessive pressure in the cylinders, when the engine begins to "independently" remove exhaust gases, re-burning them;
- “aged” valve stem seals that have lost their elasticity and gradually let oil into the manifold and then into the combustion chamber.
Clue: significantly increased oil consumption.
Actions: produce complete diagnostics engine, measure compression, decarbonize if necessary, replace worn parts and oil.
Black smoke from the exhaust
What it looks like: toxic exhaust of a pronounced dark color.
Thick black or gray smoke from the exhaust pipe is clearly visible when daylight and contains particles of soot formed due to non complete combustion fuel.
Cause: over enrichment air-fuel mixture due to a clogged air filter or leaking injectors; low-quality fuel, causing the so-called detonation combustion; flooded candles or malfunctions in the operation of the electronics that control the mixture formation process.
Clue: increased fuel consumption, reduced engine power, starting problems.
Actions: start with affordable - update gasoline, check air filter, sensors and pressure regulators, view the spark plugs. If the smoke remains - urgently in the service.
In any case, no matter what color, consistency and saturation the smoke from the exhaust pipe is, this is the SOS signal that your car gives. Be careful, use quality parts and components, do not skimp on diagnostics and choose only proven products and brands.
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Smoke emitted from exhaust system, should be colorless. On cold days, the first few kilometers before the water evaporates from the system, the exhaust gases can be colored in White color. During intensive acceleration of diesel cars without particulate filter exhaust gases become dark in color. This is normal and should not cause concern. In turn, in cars with FAP / DPF particulate filters, white smoke can appear during the combustion of soot particles. However, if intense coloration exhaust gases observed for a long time, this is already a sign of a serious malfunction. Components such as a turbocharger, injection system components, cylinder head gasket or even piston rings can be damaged. What else can you check if you see smoke of an unnatural color from the exhaust pipe?
White smoke
If the car leaves behind a lot white smoke, then it is likely that the cylinder head gasket or even the head itself is damaged. Exhaust gases are white because coolant enters the cylinders through a crack in the head/gasket. To verify this, it is not enough just to 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 excess pressure in the system during movement. Only such tests guarantee the accuracy of diagnosis.
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 it is probably the fault of the injectors, which, instead of giving a small dose of fuel, pour too much and with wrong pressure. In this case, you will need to either repair the nozzles or replace them with new ones. Repair, 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 excess burned motor oil. The source of this phenomenon, as a rule, is a turbocharger (drives oil into intake manifold). But at the same time, the blue exhaust can be caused by wear and tear. piston rings. And if, after a short time, the exhaust becomes normal again, then most likely we are talking about valve guides or their seals. The elimination of such defects often requires complex repair turbocharger (about $300) or overhaul cylinder- piston group. Depending on the car, the cost of such services reaches several thousand dollars.
The color and intensity of the exhaust can be considered fairly objective indicators for assessing the condition of a diesel engine. By these signs, an experienced driver can determine its malfunction, degree of deterioration, efficiency. If the engine is serviceable and properly adjusted, then its exhaust gases are practically colorless, and thick black smoke may appear only immediately after starting the engine. In principle, this happens in almost all cars with a diesel engine, and this phenomenon is quite normal. Why is exhaust fumes this color? The main coloring element is soot, or rather its smallest particles. By the way, soot itself is not toxic, but is harmful to health. a large number of aromatic hydrocarbons that soot absorbs and retains. Another dye that gives the smoke a bluish tint is completely unburned hydrocarbon particles.
So, if the exhaust gases become colored, then you need to look for a malfunction in the engine. If the smoke is black or close to black, then the cause may be a malfunction of the injectors. It is also possible that there is a malfunction in fuel pump high pressure when fuel is overdosed or in other fuel supply elements. It's also worth checking the air filter. Black exhaust can also appear with severe cylinder wear, burnt piston rings, wear camshaft and with improperly adjusted clearances in the valve mechanism.
Sometimes the exhaust turns white. This can be considered normal only when the engine is running in winter, at low temperatures. In this case, the white color gives the exhaust gases condensed steam, which appeared as a result of a temperature difference. If the white color of the exhaust gases appears only at the time of starting, and then, after the engine has warmed up to operating temperature the color disappears, then the most likely reason is the glow plugs, which began to work poorly.
Some diesel engines during warm-up emit bluish smoke. This is possible if oil enters the cylinders, for example, due to an excess of its level in the crankcase, wear piston-cylinder group, piston rings, oil seals, guide caps. It may also be related to poor quality fuel and engine temperature, which is below the optimum.
In addition to the above methods for assessing the color of the exhaust, which is called "by eye", in car services this can be done more accurately using special devices for measuring the smoke content of exhaust gases and use this data to assess the condition of the engine.
Many experienced drivers they know that it is possible to diagnose some car malfunctions by the color of the exhaust gases. If, while the engine is running, the exhaust pipe begins to emit smoke of various colors - from white to black, this is clear sign malfunctions in the vehicle.
Photo: JT (flickr.com/photos/environmentblog/)
And here the main thing is to respond to warning signs in a timely manner, to identify and eliminate possible faults or breakdown to avoid major and costly repairs.
Today we will try to figure out what types of malfunctions can be diagnosed by the color of exhaust gases using an injection and carbureted gasoline engine as an example.
But before proceeding to the consideration of faults, it is necessary to say about some general points.
First of all, it is worth noting that at the time of the car factory in cold weather, white smoke is absolutely normal, provided that it disappears when the engine warms up properly. The cause of the whitish haze is the steam generated from the combustion of condensate formed in the car's fuel system.
Also, a barely noticeable white smoke coming out of the exhaust pipe in cold weather is not a malfunction. However, in hard frost this smoke can be quite noticeable, but this is also quite normal, just like steam from the mouth when warm air is exhaled.
It is important to be able to distinguish between steam and white smoke. It is quite easy to do this, the steam is translucent and quickly dissipates after exiting the pipe. The smoke is denser and stretches in a plume, quickly dissipating only in the presence of wind.
But the smoke from the exhaust pipe can be not only white. It can also be black, and bluish, and gray.
The color of the smoke changes depending on the quality fuel mixture(as a rule, re-enrichment with fuel), as well as from what was mixed with the fuel mixture during engine operation. And it can be engine oil or coolant. These impurities do not burn completely in the cylinders and paint the exhaust in different colors.
Obviously, the fuel supply mechanism is responsible for the poor-quality preparation of the fuel mixture. And the ingress of foreign liquids into the cylinders indicates excessive wear. individual parts piston group.
But not everything is so clear. For example, the situation may develop according to the following scenario: the engine cooling system has broken down, which begins to periodically overheat. This entails burning the piston rings, which begin to let oil into the cylinder and smoke appears from the exhaust pipe.
You can replace the rings, for some time the smoke will stop, but if the root cause is not eliminated - bad job cooling system, then after a while the malfunction will make itself felt again, the smoke will appear again.
That is, the 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 determine exactly what the root cause is, it will be necessary to analyze and compare all the available facts.
For example, consider several possible situations ...
injection engine
The presence of malfunctions or breakdowns in an injection-type engine equipped with an injection system, the car's exhaust system signals the output of black, blue or white exhaust.
black exhaust
in engines of this type, as in carburetor counterparts, the formation and removal of black exhaust gases can occur. Often this problem occurs due to the supply of too rich a fuel mixture.
Such a malfunction manifests itself due to the breakdown of any sensor or the failure of the control unit of the fuel supply system. IN this case it only takes simple replacement sensor (if it turned out to be faulty) or replacing the entire control unit (a more complicated and expensive operation).
Additional reasons for the appearance of a black exhaust may be the needle hanging in the nozzle on the intake system, the constant supply of a small voltage to the working injector, or the appearance possible problems in the operation of the control unit (for example, changing the frequency of pulse transmission).
White or blue (gray) exhaust
Often white or gray exhaust appears due to the ingress of water into the fuel or the 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 due to breakdowns in the main boost turbine.
carbureted engine
In a carburetor-type engine, the appearance of malfunctions is manifested by the output of exhaust gases, which also have white, gray and black colors.
white exhaust
As in the case with injection engines, in this type of internal combustion engine, white exhaust indicates the presence of water in the fuel. Causes of water in fuel tank quite a lot - the formation of condensate in the tank and in pipelines; high air humidity when refueling; water ingress from the cooling system.
Other reasons for the appearance of white exhaust include a decrease in the tightness of the block head gasket, the ingress of refrigerant liquid into fuel cylinders, water leakage from the system that is responsible for heating the carburetor.
In some cases, thick white smoke is caused by the engine not warming up to the correct temperature, which can leave some water in the exhaust system (this is why short trips are very harmful to the car, especially in cold weather).
gray exhaust
Blue exhaust or of blue color appears as a result of some oil entering the combustion chamber. Often this may be due to the wear of the cylinders and pistons of the internal combustion engine fuel system.
The degree of wear of parts is determined by measuring the level of compression. If the compression level corresponds to the set values, therefore, valve seals - bushings and cuffs - are responsible for the formation of a blue exhaust.
Often, a blue exhaust is manifested due to occurrence, breakage or wear of oil scraper piston rings.
The most likely reasons for the withdrawal of blue exhaust gases can also include a decrease in the elasticity of the cuffs and rings in the bushings and valve plates; a high degree wear of valve seats and main parts of cylinders and pistons; high oil level in the crankcase; as well as the use of low quality fuel with oil impurities.
black exhaust
Exhaust in black carbureted 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 fuel mixture to the carburetor.
TO additional reasons removal of black exhaust gases from the exhaust system can be attributed high level fuel in a float-type chamber; poorly open damper for air supply; the presence of blockages in the jet; wear of the holes of the jets; the use of jets of inappropriate sizes and types; system valve failure idle move; faulty spark plugs.
Of course, these are just a few probable reasons for which smoke may appear from the exhaust pipe, but the main thing is that now you know in which direction you need to dig in order to get to the bottom of the true cause of the malfunction.
The exhaust gases of any car contain quite a lot of information about it. And you can find this information different ways. The scientific approach is common in perfect laboratories automotive industry or in modern and well-equipped workshops. And complex and smart devices stuffed with modern electronics are able to determine the condition of the engine literally by smell. A modest ordinary driver has a very modest arsenal of instruments, and most drivers have nothing, not even an ancient gas analyzer. But still, if smoke comes out of the exhaust pipe like a steam locomotive, any driver will understand that something is wrong. And each malfunction has its own color in the smoke, which can be quite easily determined by eye.
black exhaust indicates a problem with the power supply. After all, only correctly cooked burns normally. working mixture. And if fuel prevails over air in it, then the exhaust will contain under-oxidized carbon particles, that is, soot (normal combustible mixture consists of 1 kg of gasoline and 15 kg of air, theoretically necessary for the complete combustion of gasoline). Most often, clogged air jets or a leaky float chamber valve are to blame for such a malfunction, which increases the level of gasoline in the float chamber, and thereby constantly enriches the combustible mixture in all engine operating modes. A clogged air filter can also be the cause of over-enrichment. Many drivers change it according to the instructions of the factory, for example, after 10,000 km. But not many take into account the fact that this prescription (especially for foreign cars) is valid for clean European roads who wash frequently special formulations. But if you drive on the roads of Russia or the CIS, then you need to change the air filter not after 10,000 thousand km, but after 5,000. And rural drivers should change the filter even more often.
white exhaust speaks of excess moisture. Not many people know that water is one of the combustion products of gasoline. When the engine is cold, the vapors have traveled a long way from the combustion chamber to the tailpipe before condensing into a mist. So if in cold weather you have dripped from the muffler after starting the engine, don’t worry - this is normal, and your car’s engine, or rather its power system, is normally configured. And as the engine and its muffler warm up, foggy condensate ceases to fall out and the exhaust becomes colorless, because water vapor, unlike fog, is quite transparent.
If, after warming up the engine, white smoke comes out of the exhaust pipe, then things are bad. Most likely, that broke through the gasket between the cylinder head and the engine block. And if the gasket is torn, then the cylinder is choked with coolant and, like a pump, drives it into a hot exhaust manifold. The result of this malfunction is clearly visible, and comes out of the exhaust pipe in the form of puffs of white smoke. And if you dismantled the engine, changed the gasket, and then starting the engine saw the same picture, then do not rush to panic. This itself will pass gradually, since all the shkers and nooks and crannies exhaust system, are literally soaked in coolant, and it takes some time for them to dry.
Exhaust blue tint. This color is given to it contained in exhaust gases tiny particles of oil. And if a car that has run a lot begins to eat oil in liters, then it becomes clear to anyone, even a novice driver-teapot, that a major overhaul of the engine is simply necessary. But you should constantly monitor the oil level, even when the engine is in in perfect order and also check if oil is leaking from the outside. And if after parking the car at night, you do not observe oil stains under the engine, then everything is in order with the tightness of the oil seals and gaskets of the engine of your car.
If the engine of your car is covered with a layer of greasy dirt, then do not be alarmed. There is no serious malfunction here, most likely you will just need to clean the crankcase ventilation system. If it is clogged, then the pressure in the crankcase is constantly increased and the engine sweats oil from this. The system should be cleaned approximately once every 40 thousand mileage. Otherwise, it will come to the point that the oil will spurt, and normal and quality oil worth the money (o right choice oil, I advise you to read). After cleaning the ventilation system (you can find out where it is in the manual of your motor), it is advisable to wash the engine, because a clean motor cools well. Moreover, with a clean and normally working ventilation system crankcase gases, your engine will stay clean for a long time.
And also, on a fairly run car, engine oil(and therefore your money) can literally fly out the pipe. Any driver can see it in the rear view mirror worn out car when you step on the gas pedal. And the calculation is quite simple - the denser the bluish exhaust, the more money it will take to repair the engine. And attempts to fill in the oil thicker, and make the ignition point later, will not give anything, except for unnecessary gestures on the hood. After all, you or the car service repairmen will still have to climb the hood (and not for one hour). And many often ask the question: what to change the rings or valve seals? I will say that there is nothing to guess here - everything needs to be changed (although more often, of course, it is a matter of worn rings, it all depends on the mileage of the car). Who will have to repair the engine, I advise you to read, and it will not hurt.
IN different modes engine operation, engine oil enters the cylinders in its own ways. For example, when abrupt start cars, both throttle valves carburetor open and the economizer and accelerator pump are activated simultaneously. The charge density increases and the combustible mixture is enriched, and the pressure in the combustion chambers increases accordingly. But while the speed of the pistons in the cylinders is relatively small, then with worn rings, hot gases break through into the engine crankcase. Then, having captured oil vapors, they return to the carburetor through the crankcase ventilation system, and then are naturally sucked back into the engine cylinders. Here, the combustible mixture burns together with the oil (as in two-stroke motors, which constantly smoke) and we observe the result at the outlet of the muffler. And if the car smokes with bluish smoke during acceleration, then, of course, worn rings are to blame in most cases. And if the driver has achieved a mileage that adds about 200 - 300 grams of oil for every 100 km of run, then not only worn rings, but also worn pistons can already be the culprit.
Now consider a situation that will determine that the cause of excessive oil consumption is due to valve seals. If we brake the engine, then the throttle valves are closed, and the speed is still high. And as a result of this, on the intake stroke in the engine cylinder, the maximum vacuum. Oil from the engine head through a worn oil seal (or maybe through a worn valve guide and the valve stem itself, it all depends on the mileage) is sucked into the combustion chamber and exits through the muffler. The same thing happens at idle.
And the last. Replacing rings or valve stem seals, you will definitely eliminate oil consumption and engine smoke. But this can only be achieved if your engine is not very high mileage(every car is different). But with more significant runs, when, in addition to the valve seals, the guides and valve stems themselves are also worn out, replacing the seals will not work. The same applies to piston rings. With significant runs, when both the piston and the cylinder wear out, naturally replacing the rings will not bring anything useful.
