When black or white smoke is coming from your engine then it’s not good. Your car’s tailpipe though is a good place to start for figuring out the specific cause and just how severe the problem might be. Various colors of smoke often means that various regions of the engine have a problem. Here’s what you ought to know if you observe black smoke, white smoke or a burning odor originating from your vehicle, or if it is merely steam from a very hot engine on a chilly day.
If you have a car, you must have wondered why the engine is smoking. Car enthusiasts are sure: looking at the color of the smoke coming out of the exhaust, you can find out what kind of breakdown occurred in the engine. Moreover, a smoking car may present its owner in a disadvantageous light.
The main reasons why the engine smokes
When the engine is cold, heavy smoke may come out of the exhaust system. Its color is either pure white, or bluish or dark. As soon as the temperature in the engine rises, the smoke should disappear, but this does not always happen. Why does a warm engine smoke! The reason for this is a serious malfunction. Moreover, the color of the exhaust gas also depends on the extent of the breakdown.
In some situations, you can observe smoke along with symptoms such as:
- A cold motor is difficult to start.
- The engine jams not only while driving, but also at idle.
- The tachometer shows floating revolutions.
- The motor consumes a lot of gasoline, car oil.
- The power of the power plant is reduced.
In some cases, smoke is just one visible symptom of your car’s problems.
The engine is designed in such a way as to continuously emit a small amount of exhaust gas in a certain volume through the exhaust system into the air. However, if the engine smokes at startup, why this happens, you will only be able to find out in a specialized car service.
First of all, look at the color and density of the smoke that comes from the exhaust. So you can understand why the engine smokes and troit.
Most often, the color of the exhaust gas is:
- the black;
In this case, the smoke may not be pure blue or black, but any shade of the above. However, it is generally accepted to subdivide smoke into three primary colors.
There may be several reasons why the engine is very smoking. We list the most common:
- Whitish steam exits the exhaust system due to the fact that the engine has not yet warmed up. Most often this happens in the winter, and this is not considered a malfunction.
When gasoline (or diesel fuel) is oxidized, it decomposes into carbon dioxide and water. Moreover, carbon dioxide is completely transparent and cannot be seen. Water in a vaporous state exits the exhaust system, and then, cooling, turns into a liquid. Condensation of water vapor, that is, white smoke, is the reason why the engine smokes even after kapitalki (which many drivers worry in vain).
There is always water vapor in the exhaust system, although it cannot be seen. You can check this statement: take some glass jar, hold it in the refrigerator, and then lean it against the exhaust pipe when the engine is running.
After a few seconds, droplets of water will begin to appear on the walls of the vessel – condensation of water vapor from the exhaust.
It is worth noting that the water vapor coming from the exhaust is odorless and instantly disappears.
- Why does a diesel engine or gasoline smoke black! Surely you have a picture of a moving truck in front of your eyes, behind which remains a black trail of smoke. The reason for this is soot.
The engine of the car begins to smoke black when you are abruptly gaining speed or the car is heavily loaded. This is due to the fact that the fuel mixture is not formed correctly – it is re-enriched. As a consequence of any violation of mixture formation – the engine begins to expend fuel. The conclusion from the foregoing is as follows: a breakdown is most likely in the fuel system or in the engine control system.
- Why does the engine smoke blue smoke!
To make it clearer, imagine a motorcycle with a two-stroke engine. If the driver adds too much oil to the fuel mixture, the exhaust gas has a pungent smell of burnt oil. The same can be seen when working with a chainsaw, its engine is also two-stroke. In all these cases, the appearance of thick bluish smoke, which is poorly dispersed. For some reason, too much oil begins to flow into the engine cylinders of the machine. It is clear that the mode of operation of the motor, the duration of downtime, the level of heating and other conditions affect how thick the smoke will be and what its volume will be.
Of course, such smoke is not pure blue, it looks more like steam, but if you sniff, you will smell burnt oil. If you lean against the exhaust paper, it will also leave specific traces, in addition, oil consumption will increase.
The cause of the breakdown is usually the engine itself: its parts have become unusable.
- Why does the engine smoke with white smoke and stink! This situation is similar to that described in the first case, but the smoke does not disappear, even when the engine is fully warmed up, and the street is summer.
In addition to oil, antifreeze enters the engine cylinders. During its condensation, white vapor forms, but it disappears quickly enough. However, there is one caveat: the antifreeze used may differ in properties and structure. This means that the vapor can be any shade of white, dense and poorly dispersed. Because of this, the owner of the car may get confused about what is happening. See if the consumption of antifreeze has increased! The cause of the malfunction can be both the cooling system and the motor malfunction.
Having looked more closely at such a situation, we can conclude that in reality it is not so simple. The engine may be faulty, while the breakdown is quite serious. Determine what kind of repair is required, only by the shade of smoke coming out of the muffler, it will not work. Any suspicions should be checked at a service center.
There can be many reasons why a gasoline engine smokes white smoke. First of all, when disassembling cylinders, it is worth paying attention to glow plugs. If a scum appeared on them, it means that water has entered the engine. As soon as the cylinders and candles located in them are inspected, they should be replaced or repaired. It will not work out independently. So go to the nearest service station.
Often used antifreeze is poor-quality, and when the engine comes in contact with such antifreeze, its elements are covered with corrosion. If low quality coolant leaks, the engine will begin to deteriorate from the inside. And to repair such a motor is unlikely to succeed.
How to determine that antifreeze enters the combustion chamber! To do this, unscrew the cap from the expansion tank. If you feel a strong burning smell, and the amount of antifreeze in the tank is insufficient, an oil film is floating, then you have encountered the malfunction described above.
What causes blue smoke to come out of the exhaust!
Why does a diesel engine smoke blue! Most likely, oil has entered the engine cylinders. It begins to burn, and a bluish smoke appears, it does not dissipate and smells of burnt oil.
The bluish tint may vary: it all depends on what oil is poured into the engine, what is the temperature outside. How to determine that not a normal exhaust comes out of the pipe, but smoke, which indicates that the engine has broken! Constantly monitor the oil level: as soon as you notice that its amount has decreased, then the engine is malfunctioning.
It is possible to detect a breakdown not only by looking at the exhaust, but also by attaching a white paper sheet to the exhaust pipe. Oil stains appeared on paper! So the reason why a cold diesel engine smokes blue is because oil enters the combustion chamber.
Why the engine smokes white smoke with a blue tint
Among the reasons why the engine smokes heavily with bluish or bluish smoke, there are:
- Wear and tear of valve stem seals.
Why does a gasoline engine smoke cold! If the car owner asks this question, taking nothing to diagnose, the severity of the failure increases every day. Immediately after the engine has been started, large puffs of smoke can be observed, but as soon as the machine warms up, its quantity decreases.
The fact is that the valve stem seals begin to soften due to a rise in temperature. Caps quickly become unusable due to too much clearance in the valve sleeves, poor quality of the material from which they are made, and also a large volume of crankcase gases with severe wear of the cylinder-piston group.
The key role is played by the quality of the material used to create the valve stem seals.
- The occurrence of oil scraper rings, their wear.
With such a problem, the oil scraper rings do not remove the oil film, so too much oil enters the cylinders. That is why the engine will “eat” oil in large volumes. One of the possible solutions is to make the oil scraper rings deoxidized. However, after such a procedure, the engine requires careful attention, since the rings will lose their spring properties. As a result, the occurrence of oil scraper rings will occur again.
It is more difficult to establish the reason why the engine smokes when the lower rings lie. In this case, there will be a nominal compression, and since the upper rings are in good working order, sizing will not save you from the problem.
In particular, the CPG may wear out or occur compression rings. This happens when the oil scraper rings do not lie, but are worn in friction pairs.
All this explains why the engine smokes heavily. The volume of gas that goes through the recirculation system is much larger than expected. How to determine what the reason is! Open the oil filler neck when the machine is running and idling. If the cylinder-piston group, as well as the crankcase gas recirculation system work without breakdowns, then the air flow will enter the throat or leave it a little. You can verify this with a paper sheet. When crankcase gas exits the throat with a high speed, this means that the unit needs to be repaired. Look at the color of the gas coming from the oil filler neck. When the engine is serviceable, it should not have any shade.
- The turbine is out of order.
Why does the engine smoke hot if a turbocharger is installed on it! If the turbocharger is faulty, turbine oil is refilled. That is, the oil that must enter the turbine bearings, due to broken seals (usually turbine shaft seals), enters the inlet tract.
Identify such a breakdown will turn out quickly. Just remove the duct that goes from the turbine to the motor at the bottom. See if there is oil inside or not. Typically, a thin white woven fabric is placed in the nozzle in front of the throttle. Install the pipe. Then press the accelerator pedal several times and check the fabric. If there are oil stains on it, then the turbine has broken.
Why does the engine (diesel or gasoline) still smoke with bluish smoke!
- The crankcase recirculation system is clogged.
The engine is designed so that there is always a vacuum inside it. It is provided due to vacuum in the throttle region, as well as by vacuum pumps (in some cases). One way or another, but crankcase gases that have been pumped out are sent to the intake manifold. However, in the crankcase there is not directly gas, but a peculiar fog with oil droplets. Therefore, prior to the discharge of gases into the intake manifold, they are separated. The crankcase gas recirculation system is designed for this. When it is faulty, together with crankcase gas, oil microparticles enter the inlet. This is the answer to the question of why the engine smokes a lot.
- Poor quality oil.
The quality of the oil used plays a key role. If you purchased a fake oil, then its characteristics will be impossible to determine. Nobody knows how it will behave during separation in a crankcase gas recirculation system, how it will respond to elevated temperatures in the cylinders.
In addition, it can simply overheat. And if this happens, it will lose its lubricating properties. Professional racers understand this, so they install oil temperature sensors in the engine, additional coolers and the like. It is clear that such elements are absent in the factory equipment. An ordinary car is not designed for ultra-high loads. And, as you know, the cooling of the bottom of the pistons occurs precisely due to oil.
Of course, during quiet operation, the oil will not overheat. But imagine: in the thirty-degree heat you will go to the cottage. Your whole family will sit in the car, and the trunk will be full. At the same time, the engine is hidden under protection (after all, in some regions it is impossible without it), which will not allow the oil in the crankcase to cool. In addition, you will go uphill, then all of the above 100% will lead to overheating of the oil. Now it is necessary to fill in new engine oil.
- Candle wells are located deep.
If the engine of your car is 16-valve, then its main drawback is deep candle wells, in which there are many joints of connected parts. Moreover, one joint goes clockwork, the other – through the air. Sometimes oil is thrown from the well into the suction pipe of the motor. Ultimately, the engine begins to smoke. How to make sure that this is the reason! Remove the candle tips. Did you see the oil on them! It follows that the laying of candle wells does not fulfill its purpose. Add to this that the intake manifold is leaky and you will answer your question why the engine is smoking.
In addition to all of the above, the appearance of smoke can occur due to not quite standard breakdowns. For example, why else does the engine smoke white and stink of oil!
The reason is a small crack in the motor, which is not easy to detect. Through it, oil flows into the inlet or into the cylinder, an oil leak occurs.
It also happens that the owner of the machine uses fuel for two-stroke engines (with the addition of oil). And then he asks why the engine smokes on cold or hot.
Why does a diesel engine smoke black smoke! Such a sign indicates that the engine is operating on a re-enriched fuel mixture. Moreover, the shade of smoke is both dark gray and deep black. The blame for all is soot, formed due to inefficient combustion of fuel. Most likely, a breakdown occurred in the fuel supply system.
In addition to black smoke, there are a number of signals that indicate this malfunction:
- engine starts with difficulty;
- increased fuel consumption;
- power is reduced;
- catalysts burn and the like.
Why does the engine on which the carburetor injection is installed smoke at idle! This happens due to overflow in the float chamber. To fix the problem, you need to clean the nozzles on the carburetor. It is through them that air is supplied. In addition, it is recommended to inspect the needle valve.
If the engine is injector, it can smoke with black smoke when electronic sensors cease to function properly. Depressurization of injector nozzles may also occur. As soon as the nozzles begin to pour, an excess of the fuel mixture is observed, it enters the combustion chamber. Excess fuel takes part of the lubricant from the cylinder walls and enters the crankcase.
How to determine that fuel has fallen into oil! In this case, you will smell a strong gasoline. Sometimes there is an increase in the oil level in the engine, as gasoline gets into it.
Why is the diesel engine still smoking black smoke! This is often due to low quality fuel.
The following damage may also occur:
- the nozzles are worn out;
- the air filter is dirty;
- the speed control in the fuel injection pump is broken;
- high pressure fuel pump is faulty;
- the turbine is out of order.
The high-pressure fuel pump is considered the most complex element of the fuel supply system installed on diesel engines. For this unit to function properly, lubrication in a diesel engine is required. If the fuel is of poor quality, then the fuel pump will fail before the due date.
Tricky car owners who know why a car’s engine is idling is hoping to sell it by first adding an additive. The engine temporarily stops smoking, and a reckless buyer can fall for the trick, becoming the new owner of a broken car. The fact is that not one additive can cure a faulty engine.
If the engine smokes at idle and you know why, the additive “Wynn’s Stop Smoke” will eliminate the largest amount of exhaust, make the motor work almost silent. But pouring an additive is not the same as repairing it. Such manipulation will hide the malfunction of a used machine.
When should you use an anti-smoke additive:
- If the engine is broken, and you need to hide this fact.
- Slow down motor wear.
- Extend the time of his work without contacting a car service center for global repairs.
Knowing the true reason why a diesel engine smokes, you can use an additive that will reduce gas emissions by 30%. Sometimes during the testing of additives it turned out to reduce the amount of exhaust smoke by as much as 70%. However, it is worth remembering that this indicator is determined by how much the engine is worn out and what is the methodology of its functioning.
The additive consists of substances such as barium and calcium. Their use will be advisable in harsh climates, as well as when the engine is operating in forced mode, and its work is not well organized. Using such additives, you will get an increase in the cost of fuel by only 3-5%.
Additives based on alkaline earth metals act comprehensively:
- The diffusion flows in which the reactants are located become more intense.
- Carbon microparticles begin to burn instantly in cylinders.
What is the main advantage of using smoke additives!
Poisonous substances are neutralized, therefore, the exhaust gases become cleaner. At the same time, the engine not only does not smoke, but there is practically no environmental pollution.
But you can only use additives when you know exactly why a diesel engine or a gas engine smokes white smoke.
By and large, smoke additives simply make the oil thicker. The viscosity of the lubricant increases, so only a small amount of it enters the piston, where it is burned. But since there is little lubrication in the motor itself, the leakage is insufficient, the elements of the motor begin to wear out quickly. The power unit functions practically unlubricated, overheats. It is clear that such exploitation reduces its resource. Of course, the additive will help temporarily get rid of smoke, but in the end it will just kill the engine of your car.
Basically, all anti-smoke additives contain the same substances and act on the engine similarly, and it does not matter which brand you choose. Typically, they contain molybdenum disulfide, ceramic microparticles, detergent components, that is, all known surfactants (surfactants), as well as other additives. Such a composition has been developed so that the additive:
- created a polymer film on the treated surface of the motor to protect it. Due to this, the resource of the power unit increases;
- filled small microcracks, sinks, places of wear, supporting the geometry of the motor elements. As a result, backlash is reduced, smoke from the exhaust pipe disappears;
- cleaned oil, as well as contaminated motor surfaces.
Most companies producing such additives claim that their product will help save on fuel, improve compression, and increase engine life. In practice, no noticeable changes for the better usually occur. However, the amount of smoke leaving the exhaust is reduced due to the action of the chemicals that make up the additive. It is worthwhile to soberly assess the possibilities that an anti-smoke additive gives. Restore the engine with it will not work. And smoke neutralization is also a short-term effect.
Before pouring any additive into the engine, evaluate all the advantages and disadvantages of using this product.
The main advantages of using an anti-smoke additive:
- friction between working surfaces in the motor is reduced, which means that engine life is increased;
- the smoke emitted through the exhaust system is neutralized;
- the engine starts to run less noisy;
- a positive effect will occur as soon as you fill the additive in the oil.
Among the disadvantages of using additives are:
– to predict what will be the result of the application of the additive is impossible. It may happen that a tired engine after you add “Antidym” will stop working at all;
– the positive effect of using the additive is short-term;
– the chemical components of the additive contribute to the formation of soot on the working surfaces of the motor. It will be difficult to eliminate it at best, at worst it will not be possible to remove it at all;
– The chemical composition of the additive can adversely affect the engine. Unfortunately, after such an additive, engine parts cannot be restored.
Of course, everyone determines whether or not to add the additive to the engine. One way or another, but Antidym really helps to temporarily get rid of the appearance of smoke, while not eliminating the true cause of the malfunction. Treat all kinds of additives carefully, not forgetting the disadvantages of using such formulations.
For some reason, there is no way to go to a car service to determine the cause of smoke! Then the additive “Antidym” will help to temporarily mask a brewing problem with the power unit.
Dmitry Petrov is an engineer who specializes in materials science, and has a deep passion for all things related to automotive technology. He is a true motorhead at heart, and spends much of his free time tinkering with engines and studying vehicular dynamics.