Many car enthusiasts and owners of used cars are faced with the problem of smoke when starting the power unit, or when reaching high speeds, and do not understand where it comes from. In some cases, the engine emits white smoke or black smoke. Of course, this is an indication that there are some problems with the caps or piston rings. Below we will talk about what to do when the engine smokes, how to understand the rings or caps that are causing the smoke in the engine.
Cause of smoke in the exhaust pipe
In order to understand the question of why the engine smokes, you need to have an idea of what happens in it during operation.
A fuel mixture is formed in the combustion chamber, which is compressed by the piston and ignited by a spark from the spark plug. The mixture is supplied through the inlet valves, and the spent mixture is discharged through the exhaust valves. The pistons have special oil intake rings; they are needed to collect excess oil on the cylinder walls so that it does not enter the combustion chamber.
The engine valves also have special seals (caps), which serve to ensure that the oil located in the cylinder head does not enter the combustion chamber. In addition, spark plugs also play an important role, and if they have a weak spark, or the gaps between the electrodes are incorrectly set, then the fuel mixture in the engine will not burn completely.
Based on this, we can identify the following causes of engine smoke.
- Spark plug . If the spark plugs are faulty, that is, they produce a weak spark, or the gaps between their electrodes are set incorrectly, then the fuel mixture does not burn completely and is discharged from the combustion chamber with blue smoke. In the most severe cases it may be black.
- Piston oil intake rings. As stated above, oil intake rings perform a function related to cleaning the cylinder walls of excess oil so that it does not enter the combustion chamber. They are subject to a powerful frictional force. If they wear out, the oil enters the combustion chamber and ignites along with the fuel mixture. In this case, black smoke appears. Similar functions are also performed by engine rings, which also remove excess oil from the surface of the cylinders and can wear out over time.
- Valve caps. These are seals that serve to prevent the oil in the cylinder head from entering the combustion chamber, and are made of dense rubber. When it wears out, the lubricant enters the combustion chamber and ignites. This produces white (or bluish) smoke.
The last two reasons for smokiness will be discussed below. If a car owner notices the appearance of blue or dark blue smoke, he needs to pay close attention to the operation of the power unit’s spark plugs and have them diagnosed or replaced.
You need to remember that sometimes the cause of smoke in the exhaust pipe can be bad gasoline. It may contain various additives or additives that will create black or other colored smoke. This problem usually disappears when refueling with other fuel.
Diagnosis of faulty engine oil rings
As stated above, if the engine smokes black, then the whole problem is that the piston oil rings are worn out and lubricants enter the combustion chamber.
Ignoring this problem can lead to the fact that the rings will not remove the lubricant, and therefore it will need to be constantly refilled. In addition, the rings may become stuck and will need to be de-coked. You can learn how to decarbonize stuck rings from other publications. But it is better to do this at a specialized service station.
Now let's move on to consider the question of how to diagnose this problem.
There are two ways, the first is a compression test, which will be discussed in detail below.
Second, this is diagnostics while running power unit.
In order to determine the problem with the rings, you need to mandatory warm up the engine until operating temperature, since this problem only appears when the power unit is running hot.
Then press the gas pedal, giving standard or increased speed. If with exhaust pipe black smoke will come out, which means the problem is in the rings and they need to be changed.
How to replace the piston rings in this case. Here you will have to disassemble the cylinder head, remove the pistons, buy a new set of rings and replace them. If the car is foreign-made, then it is better to entrust such work to specialists, since doing this without removing the engine will be problematic.
It is important to remember that if the problem is in the rings, then the engine will generally have difficulty starting after a long period of inactivity.
Diagnosis of faulty valve caps
If the engine smokes white, then the problem is in the caps. White smoke can also have a bluish tint. Based on this, the car owner urgently needs to change the seals on the valves, otherwise he will experience high engine oil consumption.
This problem can be detected when the engine is running cold, or while driving.
Let's consider the first case. The car enthusiast should park the car in a garage or other place and wait until the engine cools down. After this, put it in neutral gear and start the engine, giving speed.
When starting in this way, white or bluish smoke will pour out of the exhaust pipe. This means that oil enters the combustion chamber through the valve caps.
The second method requires the driver to be observant. When the car is moving, you need to accelerate it, then brake the engine, and press the gas pedal again, giving significant speed. In this case, you need to constantly look in the rearview mirror. If a white or blue smoke, which means you can safely diagnose a malfunction of the caps.
What to do in this case. This problem can be solved in your garage. You just need to remove the old seals and replace them with new ones. This type of work does not require great skills and even a beginner can handle it.
It is important to remember that if the car still smokes with replaced oil seals, then the problem may be in other engine components, so in this case it is better to contact specialists and carry out professional diagnostics.
Diagnostics using compression
The above problems with the power unit can be identified through special diagnostics using a compression meter. This is a device that measures pressure. You can do such diagnostics in your garage.
To do this, you will need the help of a friend and the presence of the device itself.
To carry it out correctly, you need to adhere to the following algorithm. First you need to put the car in the garage and warm up its engine to operating temperature.
After this, disconnect the spark plug of the first cylinder and insert a compression gauge there. Using the starter, start the engine for a few seconds (crank the crankshaft), and remember the pressure that the device shows. Next, you need to pour no more than 20 grams of oil into the cylinder chamber and turn the crankshaft again. If the pressure in the first case is low, and in the second case it increases, then the problem is in the piston rings and they definitely need to be changed.
As you can see, there is nothing complicated in such a diagnosis, but it helps to identify one of the problems with the appearance of smoke.
It is important to remember that the loss of engine power during high speed or loads also indicates that the piston rings are worn.
Cause of smoke different color from the exhaust pipe may indicate several problems in the power unit. If they are diagnosed on time, then large deviations in engine operation will not appear. If you start it, then serious breakdowns may occur, and large costs for their correction may occur.
Among possible reasons Increased oil consumption can be noted, in order of difficulty of elimination:
- oil leaks through leaks in gaskets, oil seals, as well as cracks in the engine crankcase, cylinder block, oil pressure sensor, etc.
- wear valve stem seals
- wear of the cylinder-piston group
- waste of oil due to its poor quality
The first group of reasons is determined by visual viewing. Eliminating such causes, with the exception of the BLOCK HEAD gasket and cracks in the cylinder block, is quite simple. You just need to replace faulty parts (seals, gaskets). The exception here is the head gasket and cylinder block. To replace them, it is necessary to remove the camshaft (with all the ensuing consequences), and then the head itself; or even completely disassemble the engine. Of course, such an operation will not be difficult for an experienced mechanic, but for an ordinary car enthusiast...
The second reason is wear of the low-removable caps. We will talk about the signs of the need to replace them below. This operation also usually involves removing the camshaft (one or more, depending on the car model). However, there are cars on which this is not necessary. However, these are quite rare cases.
Finally, wear of parts of the cylinder-piston group. To eliminate it, it is necessary, as they say, to overhaul the engine. As a rule, it is timed to coincide with other repair operations, namely: replacement of liners crankshaft, repair (grinding) of the crankshaft journals, replacement of valves, replacement/reaming of valve guides, not to mention the replacement of worn (by that time) valve rockers, valve springs.
Here we look at signs that indicate symptoms similar to wear and tear valve stem seals. Here is a list of them (possibly incomplete):
Alarm fault
Smoky exhaust when over-gassing
Increased fuel consumption
Drop in power and throttle response, dips in engine operation,
Oil gets dirty quickly
Glow ignition
Note that it is not necessary for all signs to appear simultaneously.
Smoke from oil filler neck*
Which can sometimes be seen, for example, if you open the oil filler neck with the engine running. On a good (i.e. serviceable) engine, air will simply escape from there (optionally, with an admixture of oil mist, which is not a malfunction). If the engine consumes a lot of oil and there is strong smoke coming from the neck, it means the engine is worn out. piston group. If the engine consumes oil, but the neck is clear, then the problem may (but not necessarily) be in the valve stem seals.
*So this sign most likely does not indicate wear of the valve stem seals.
The threaded part of the spark plugs is coated with oil
This is also one of the symptoms of the need to replace the valve stem seals. However, not always. Those. It happens that the caps already require replacement, but the threaded part of the spark plugs is still dry. Because not too much oil gets into the combustion chamber yet, it has time to burn.
Why is the threaded part of the spark plug coated with oil under the conditions when it enters the combustion chamber? It would seem that if there are gaps in the threads between the spark plugs and the block head, they are minimal and do not exceed 0.2 mm?
Let's consider the process of engine operation. The fact is that at the moment a portion of the combustible mixture is injected into the cylinder, oil enters, while a vacuum is present in the cylinder (as well as in the threaded gaps of the spark plugs). The mixture is then compressed. Naturally, it (including the oil and gasoline contained in it) begins to penetrate into all places where possible, including the threaded gaps of the spark plugs. Then the mixture is set on fire and burns. It burns out almost everywhere, except for the threaded gaps. Because they are very small (in the region of 0.1...0.3 mm), combustion, as a rule, cannot spread into such small gaps. As a result, oil accumulates in the threaded gaps. Gasoline evaporates because the spark plugs are heated.
The candles are covered with black soot. Increased smoke from the exhaust pipe
The soot may (but does not have to) be oily. As a rule, when the valve stem seals wear out, it becomes terry. Although, too rich mixture can also give terry black soot. Blue-gray, sometimes black smoke from the muffler indicates wear of the cylinder-piston group, as well as an excessively rich mixture.
However, similar symptoms are also observed when the valve stem seals are worn out (blue exhaust when re-gasping), malfunction of the ignition system (ignition timing is incorrect, “broken” high voltage wires, distributor cap, slider, etc., as well as possibly a malfunction... alarm), violation of the fuel supply system adjustments (for example, carburetor, injectors, etc.).
Those. Black smoke from the muffler and spark plugs covered with black soot are not always evidence of an overly rich mixture. Both of these signs also appear when the valve stem seals are worn out, or when the ignition system is malfunctioning. Why?
Because if the ignition system malfunctions, the spark on the spark plugs will be defective, although in appearance it may be quite acceptable. Accordingly, the combustion of the oil-fuel-air mixture will also be incomplete. In particular, the oil and gasoline contained in the mixture will burn WORSE (than with a good spark), i.e. black soot will form, creating the appearance of an overly over-enriched mixture. For example, this is exactly what was observed in the case when it was “cunningly” broken through.
Alarm fault
It can also cause carbon deposits on spark plugs if ignition-related circuits pass through it. A common case is when some connectors in the alarm have bad contacts (when they are old and/or made of Chinese metal). In this case, the ignition will either be excellent, or “not very good,” or (for a fraction of a second) completely absent. And so - constantly.
There was a case when the car periodically stalled while driving after 10...20 minutes of driving. And after that it flatly refused to start. However, after parking for 10...15 minutes, it started up as if nothing had happened and drove as long as needed.
Note: exactly the same behavior of the car in another case was a consequence of a malfunction of the valve stem seals.
In addition, the car often (but not always) stalled when trying to drive uphill. The service technicians' recommendations to repair the power system, naturally, led to nothing at all. They only led to the expenditure of money and time for reflection. However, the problem was completely resolved after restoring the electrical contacts in the two alarm connectors (by removing them and lightly crimping the connectors).
Why did the car start after 10...15 minutes of parking? Because during this time the alarm unit cooled down a little, the contact parts of its connectors slightly changed in size (under the influence of thermal contraction), slightly shifted relative to each other (i.e. the male connector shifted slightly relative to the female connector "), there was a kind of scratching, sliding of their contacting surfaces relative to each other and contact was restored for some time.
Why does the engine sometimes stall when the car is moving uphill? Because in the alarm unit located under dashboard, when the orientation of the machine relative to the vertical changed, the alarm unit moved slightly to a different position, as a result, the electrical contacts were sometimes broken. And when the car moved onto a horizontal surface, the contacts were restored.
Smoky exhaust when over-gassing
The symptoms of the formation of smoky exhaust during over-gassing are similar - both in the case of a malfunction of the valve stem seals and in the case of a malfunction of the cylinder-piston group. The difference is that if the caps are faulty, then repeated re-gassing (4...7 times) usually leads to the (temporary) disappearance of the smoky exhaust. Those. As a rule, there is no constant smoking. Whereas if the cylinders and pistons malfunction, the smoky exhaust does NOT DISAPPEAR after several gas changes.
The reason is that in the first case, the oil that has accumulated near the junction of the edge of the valve stem and the valve stem, as a result of sharply pressing the gas pedal, is TEMPORARILY sucked through the gap between the valve stem and the guide bushing into the cylinder, which leads to several smoky exhausts when gas changes. When all the oil nearby has been sucked out, a smoky exhaust (until the oil accumulates again) will not form. Whereas in the latter case, oil enters the cylinder regardless of whether the gas pedal is pressed sharply or not; no matter how many times and with what frequency it was pressed.
When working on Idling when the cylinders and/or pistons wear out, the smoke will be thick and bluish (like old Soviet motorcycles, chainsaws of the “Friendship” type), whereas when the valve stem seals wear out, it will (at first) seem to be “bluish”. If you look at the exhaust pipe from above while the engine is running, it is not always visible. But looking ALONG the exhaust pipe, when looking from behind the car, sometimes (but not always) makes it possible to see such a bluish smoke.
Also, if when the engine is HEATED, white smoke comes out of the muffler, then this is also a sign of wear on the valve stem seals, but not on the cylinder-piston group. By the way, another reason for the appearance of white smoke on a warm engine is the ingress of coolant into the engine cylinders due to a faulty head gasket.
Note that the appearance of white smoke, which disappears after warming up, on a COLD engine, on the contrary, is a completely normal symptom. Indeed, as a result of combustion of the fuel-air mixture, water is formed, in particular. The vapors of which become visible until the engine and muffler warm up. For the same reason, drops of water may even fly out of the muffler. It often happens that water drips a little from the end of the muffler pipe.
When the muffler warms up, water vapor on its walls will no longer condense - and the white vapor will disappear. The water will stop dripping.
Too rich flammable mixture will also produce an exhaust with increased smokiness, including when over-gassing. Which, it seems, SHOULD NOT disappear after repeated gas changes.
However, in reality, not everything is so simple. There was a case when, due to too rich fuel mixture The car engine started with great difficulty “when hot” (while “when cold” it started with half a turn). After repeated gas changes, the high smokiness (blackish) exhaust DISAPPEARED. However, there was a problem - precisely in the overly enriched fuel-air mixture.
Increased fuel consumption
The fact is that the oil that gets into the cylinders during engine operation makes it difficult to burn the fuel-air mixture. Accordingly, in order to extract the required power from the engine, a larger amount of mixture will be needed than if there was no oil in the mixture.
By the way, not only valve stem seals, but also almost all other engine malfunctions also lead to increased fuel consumption, be it wear of the cylinder-piston group, a malfunction of the ignition or alarm system, or a non-optimal composition of the combustible mixture.
Decrease in power and throttle response, failures in engine operation
This manifests itself in reduced dynamics when accelerating or overtaking. You may also experience “dips” when you press the gas pedal. Those. you press the gas, and SOMETIMES the car, instead of rushing forward, seems to slow down, the engine stalls. If you release the gas pedal or press it SLOWLY, the engine runs normally. In such cases, it is usually recommended to adjust or repair the fuel supply system. More advanced ones also recommend paying attention to the ignition system.
This is often true, but not always. Sometimes, when there is a sharp increase in vacuum during the intake stroke of the fuel-air mixture (which is the result of a sharp press on the gas pedal), this vacuum is transmitted through the valve guides to the valve stem seals. If they are worn out, then a portion of oil is sucked in, which enters the cylinder, flooding the spark plug, i.e. (at first temporarily, and then permanently) turning her off from work. This explains the “failure” in engine operation. If the car is equipped with a catalytic converter, “for some reason” it will soon fail.
Oil gets dirty quickly
Yes, this is also one of the symptoms of wear on the valve stem seals, which is not known to everyone. Why does the oil become contaminated, becoming dark, then black? There are usually two main reasons:
- wear of engine parts and the entry of wear products into the oil
- the formation of soot caused by the combustion of oil contained in the fuel-air mixture and its subsequent flushing
Well, quite banal reasons, for example, malfunction (or absence) of the air filter, as a result of which dust from the air gets into the cylinders, which causes oil contamination, or simply low-quality oil that quickly breaks down during engine operation, we will not consider here.
The first is, in principle, generally known. But, at the same time, there should be metal particles on the magnetic oil drain plug. What if there are few of them or none at all?
Then, obviously, the black particles causing the oil to darken are nothing more than coke washed off the cylinder walls. After all, most modern motor oils contain quite effective detergent additives, which help wash away carbon deposits. If not for them, the result would be that the piston rings would simply become coked. Fast. Well, their presence in the oil thereby saves the engine. True, the oil takes the full blow and quickly becomes dirty.
Since carbon deposits form GRADUALLY, its particles are very small in size and, being washed off from the cylinder walls, they freely pass through oil filter and for this reason they remain in the oil, causing the need for its rapid replacement.
However, it could also be that the mixture is too rich. Which also gives black carbon deposits on the spark plugs, as well as on the surface of the cylinder. Accordingly, after this carbon deposit is washed away with oil, it will end up in the engine crankcase.
Glow ignition
It is expressed, in particular, in the fact that the engine continues to run for several seconds, or even more, even after the key has been removed from the ignition switch. Yes, and this can also be a symptom of oil getting into the combustion chamber, including as a result of malfunctioning valve stem seals. Why?
Because modern gasoline cars, perhaps all without exception (both carburetor and injection) are equipped with a system for stopping the fuel supply when the ignition is turned off. For example, if we talk about a carburetor car, then carburetors, as a rule, have solenoid valve idle speed, which shuts off the flow of working mixture when the ignition is turned off.
By the way, for reference, modern gasoline car does not have to be injected at all. For example, many military vehicles are, as before, carburetor-powered. The reason is probably clear to you: military vehicles are required, among other things, to have increased reliability and high maintainability even in an “open field.” It is clear that a knowledgeable person can clean and adjust the carburetor quickly and in almost any conditions, while to adjust injection engines you cannot do without a computer. Well, cleaning injectors in the “field” is definitely impossible without special equipment. And, in fact, the military will not carry a diagnostic computer and other devices with them just to use an injector, when it is quite possible to get by with a carburetor that has proven its reliability and quick repairability. Well, which slightly increases fuel consumption and slightly increases the toxicity of exhaust gases. And nothing more.
Then, the more electronic parts there are in a car, the higher the likelihood of them failing, for example, when exposed to an electromagnetic pulse.
So, if even when the gasoline supply is turned off, the engine continues to run at idle, it means that there is something in its cylinders that can burn. In this case, it is nothing more than oil. Located there in SUCH a concentration at which the engine is still able (but not always) to work. It is clear that when the caps wear out even more, even more oil will enter the combustion chamber, and then the glow ignition may disappear. But at the same time it will be difficult to start the car, it will increased consumption oils, etc.
The car is difficult to start when hot
If it is difficult to start “cold”, then the reason is often not at all in the valve stem seals. There are most likely more obvious reasons, such as wear of the cylinder-piston group, fuel supply failure, ignition malfunction, including, as already mentioned, alarms. And also - a malfunction of the battery, starter.
But if “when cold” the engine starts with half a turn, but when hot, paradoxically, you have to spin it with the starter for 5...10 seconds or even more (or even the car engine stalls as soon as it warms up properly), then the reason for this may well be be wear of the valve stem seals.
The fact is that in a cold engine the oil is also naturally cold. And it has a high viscosity, and therefore reluctantly seeps into the gap between the valve stem and the working edge of the oil scraper cap. When the oil warms up, its viscosity decreases (sometimes by several orders of magnitude), and it is much easier for it to pass into this gap.
However, a violation of the composition of the combustible mixture, ignition malfunctions, and alarms are also not excluded, of course.
The exhaust gas has a very disgusting, suffocating smell
It is clear that the smell of exhaust gas cannot be called natural, pleasant and safe.
However, having sniffed, say, the cars driving in the Arab Emirates (UAE), I concluded that the situation with exhaust gases there is MUCH(!) better than in Russia. It seems like there is a continuous stream of cars, but the exhaust smell is insignificant... Sometimes, even leaning close to the exhaust pipe, you somehow don’t catch that nasty smell that comes from Russian cars. One of the reasons for this, of course, is more high quality gasoline. Which, by the way, also cost much less than in Russia, at least until the ruble exchange rate sharply dropped against the dollar and many other currencies.
Yes, yes, after all, it’s exhaust gas, what can you expect from it? However, when the combustible mixture is of poor quality, incorrect (in particular, as a result of large amounts of oil getting into it), then, naturally, the smell of the exhaust becomes much, much more disgusting. In such cases, it’s worth standing near the exhaust pipe for a while while the engine is idling, and you want to get away from this smell somewhere. The neutralizer, we repeat, fails very quickly.
Therefore, if your car’s exhaust has become particularly unpleasant, suffocating, and not what it was before, you should pay close attention to engine parts through which excess oil may enter the combustion chamber. In particular, these are valve stem seals.
However, the cause of such a smell can also be a very rich combustible mixture.
Worn valve guides, valve stems
Of course, the wear of their working surfaces in itself does not indicate wear of the valve stem seals. It simply speeds it up, and significantly. It also makes it useless to replace the caps with new ones.
The fact is that if the holes in the guide bushings and/or valve stems are heavily worn, during engine operation even a new high-quality valve stem seal will be unable to fully retain oil. Which will enter the combustion chamber, as with worn caps.
So if after replacing the valve stem seals there are still symptoms of wear, then you should think about repairing (replacing) the valves and their guides. And even about major renovation(replacement) of the engine, because, as a rule, by this time its other parts also partially exhaust their service life. There is no point in changing only the bushings and valves, if in another 20...30 thousand the chain, sprockets (pulleys), rockers, pistons, rings will have to be replaced, as well as cylinder boring and crankshaft journal grinding.
How to measure play in valve guides? Roughly and approximately, the play can be considered large if, when rocking the valve stem from side to side, it feels much higher than it was on a new (repaired) engine. If it is much higher than the typical perceived play for a particular engine model. Well, for a more accurate measurement, of course, it is necessary to remove the cylinder head, remove the valves, etc.
Quite often you notice that increased smoke appears from the exhaust pipe of a car. Sometimes situations get to the point where the car is literally shrouded in clouds of thick smoke. It is quite obvious that for every car enthusiast, the appearance of excessive smoke indicates the appearance of certain problems with the car.
Let us immediately note that not always, but often, increased smoke indicates serious problems. At the same time for experienced drivers It will not be difficult to determine the cause by the color and composition of the exhaust. However, for beginners it is not always easy to understand why the engine smokes, as well as to determine the cause and identify the rings or caps. Let's figure it out.
Read in this article
White or black smoke appears from the exhaust pipe
Let's start with the main types of smoke to better understand the problem. So, white smoke from the exhaust pipe is quite normal for warming up a cold engine. Moreover, it is a mistake to believe that it is smoke. It's actually steam. Water in vapor form is a natural product of the engine.
In unheated exhaust system this vapor partially condenses and becomes visible, and water usually appears at the cut of the exhaust pipe. As the engine warms up, condensation decreases.
The colder it gets environment, the denser the steam turns out. At temperatures below 10 ° C, steam is formed even on a well-warmed engine, and in frosty temperatures of minus 20 - 25 degrees it acquires a thick white color with a bluish tint. Air humidity also affects the color and saturation of steam. The larger it is, the thicker the steam.
Note that if steam is visible in the warm season, it is quite possible that this is due to. Its shade depends on the composition of the coolant, weather, lighting, and also on the amount of coolant in the combustion chamber. Sometimes it can take on a bluish tint, resembling “oily” smoke. But, unlike oil smoke, which leaves a bluish mist in the air for a long time, steam quickly dissipates.
It is quite difficult for an inexperienced motorist to appearance determine what is the source of the smoke. In this case, you can use a proven verification method. To do this, on a well-warmed engine, it is necessary to briefly cover the cut of the exhaust pipe with a sheet of white paper, while condensed steam in the form of drops of water, when it hits the paper, will gradually evaporate and will not leave obvious greasy marks.
If this simple test confirmed that exhaust system It is steam and not oil smoke that comes out, it is necessary to take measures to eliminate the malfunction that allows coolant to penetrate the cylinders.
Most often, liquid can enter the cylinders through insufficient broaching (in winter period Often there is a leak of coolant at the junction of the block and the head), burnout and, less often, as a result of the formation. By opening the radiator cap or, it is easy to identify the smell exhaust gases and a film of oil on the surface of the coolant.
All problems associated with white smoke from the exhaust pipe require elimination of not only the direct causes, but also a mandatory check of systems that can affect their occurrence: the activation sensor, the clutch or the fan itself, the condition of the radiator, its plugs, hoses or connections. If white smoke and accompanying defects are noticed, then the car cannot be operated, as the defects progress quickly.
- Let's move on. Black smoke from the exhaust pipe indicates an over-enrichment of the fuel-air mixture or a deterioration in fuel combustion conditions. Therefore, we are talking about malfunctions. Such smoke is usually clearly visible against a light background and represents soot particles - products of incomplete combustion of fuel.
Black smoke is accompanied by high fuel consumption, often poor starting, unstable engine operation, high toxicity of exhaust gases, and often loss of power due to a non-optimal composition of the air-fuel mixture.
It is important to understand that monitoring symptoms and quickly identifying the problem will further reduce the cost of repairs and avoid serious and rapidly progressing damage to the internal combustion engine.
Read also
Why do piston rings stick? The main signs for independently identifying a malfunction, diagnostics. Do-it-yourself decarbonization of piston rings.
Good day everyone
I have a 99 premaska. I bought it in February - this is my first car :) So far I've invested a lot of money in it, starting from all the consumables/seals and suspension parts, ending with sound insulation and replacing all the acoustics around. Literally all this time, the machine was regularly in service, because... I did it for myself and literally worked for her. I left the oil change until the very last moment, because... the owner reported that the oil is not eating up, and the planned (every 10 tons) replacement will be after 3 thousand. Having traveled a little less than a thousand kilometers during this time (I didn’t travel much, periodically on business), I drove the gearbox knob to adjust the loose rocker, and at the same time, earlier than the 2 thousand indicated for me to replace it. oil, because I was impatient to change it, I even bought 8 liters from the dealer, so that without counterfeits, and rinse it first, filling in the second “set” next for the summer. They changed it with a complete drain of the old one at my request. Judging by the remainder in the canister, they filled it with 3.5 and replaced the filter, which is the norm.
When I picked up the car, returning it backwards in the box, I noticed that the entire repair bay was filled with white exhaust smoke. Standing nearby, I went out to observe the exhaust. The smoke was no longer strong, and then it seemed to go away completely. Having calmed down, I took it to the painter for minor touch-ups (scratches, scratches).
I was able to pick it up only after 3 days. As I pulled away from the parking lot backwards, I noticed the smoke, that smoke again! Finally starting to understand that something is wrong here, I again watch the exhaust. It's warm outside, about +20 in the sun, noticeably warmer than the day I picked it up from the service center. Meanwhile, the smoke began to subside again as the engine warmed up. I ran my finger and there was condensation at the end of the pipe. Everything seems to be fine. The smoke is barely visible.
I decided to drive home around the city, bypass. During the route, I periodically turned off the music and listened to the engine. Turnovers are as usual. The liquid temperature is in the middle of the scale. The oil pressure indicator and other things related to the engine on the dashboard do not light up. The sounds are all normal. Everything seems ok.
arrived, installed. Today I started googling and asking questions to experienced motorists. There were speculations about a breakdown of the cylinder head gasket and etching of coolant into the cylinder. The serviceman who serviced the car (he was not in the box when I picked up the car) suggested over the phone that it could be worn out valve seals. The only question is that this smoke did not exist before.
And finally, almost the end - in the evening, having accumulated the theoretical course of a young fighter, I come to my Masa, check the coolant level, which is 2 centimeters in the tank, and under the radiator cap - under the neck, which seems to be excellent, I make sure that there are no whitish streaks on the oil filler cap engine neck and camshafts, I start Masyanya’s heart. The plant started in a split second, then about seven seconds of quiet, flawless operation, which seemed like an eternity. And suddenly! - as if fresh grass was thrown into a fire - thick white smoke begins to pour out and slowly rise into the air. Dense smoke, obviously not condensation, and what the hell is condensation when it’s already over 20 degrees outside and in such conditions the activity of the exhaust should already be indistinguishable. Half a minute passed (no less), the density of the smoke decreased several times, becoming an exhaust that was clearly visible to the eye. My father, who volunteered to help, at my request, adds gas to idle, and the smoke screen spreads across the yard with renewed vigor, hiding everything from view. While gasping I tried to see the bubbles in expansion tank, which would indicate etching by the exhaust into the cooling system. NOTHING! The liquid, perhaps not having time to warm up, did not even move anywhere for the entire 5 minutes of engine operation, no bubbles, no twitching, no oil stains on the surface of the liquid. Nothing: (When I turned off the engine and opened the radiator cap, I also didn’t see any oil there. Under the oil filler neck, everything is also in normal mode, there is no emulsion on the cooler, the oil level is closer to the maximum. Only the yard of 100x50 meters is half hidden in the smoke. And it has a little smell it smells like gasoline, not very reminiscent of oil, and the color is not gray or black, but white. And I didn’t see any traces on the white sheet of paper attached to the exhaust.
In general, I'm completely confused.And finally, introductory (sorry, it's at the end of the topic):
engine- fp-de 1.8 petrol injector, mileage 178t
oil before change 5w-40 castrol synthetics http://castrol.com.ru/castrol/magnatec_sae40c.php
oil after change 10w-40 liqui moly semi-synthetic http://catalogue.liquimoly.ru/index....talogue_id=424
(the seller claimed that he didn’t wind it up, he didn’t need it). By indirect signs I believed him then, but now I don’t even know.
Antifreeze - blue. Just blue :) the only thing I didn’t have time to change.
I chose the oil by studying the forums, since the engine was already running, semi-synthetic should be indicated for use. I switched despite the seller’s assertion that he doesn’t eat butter. It's calmer this way. The low-temperature density figure is due to the coming summer here in Krasnodar (temperatures from 30 to 43 in the shade), I think it’s what we need. I bought Liquimoli through a friend, from a supplier, so that there were no counterfeits.
I confess, I didn’t measure the coolant level after purchase, how would I know. Maybe the antifreeze was leaving - but as I wrote above, I did not see this based on indirect signs. Option to unscrew drain plug crankcase and look for the presence of a heavy water fraction at the bottom of the oil? or again unscrew the recently replaced spark plugs and try to find “cleaner” ones that, in theory, could be “eaten up” by the coolant. Would you have time? Moreover, while replacing the old spark plugs, I noticed that almost everything was fine with them. “Almost” - because the end is slightly coked, but the terminals of the arresters are clean and reddish, I looked at the edges of the thread - well, the mixture was over-enriched, I changed it because of this fuel filters(both) in the tank, and air filter. I wanted to clean the injectors with ultrasound this week myself or at a service center. So all these metamorphoses with the engine began to occur after changing the oil at the service center. Did the cunning owner really use an anti-smoke additive in the old oil? But damn it, the smoke is now pouring out so much that it can only be calmed by a young tree if it is driven into the exhaust.
Help, good people. It’s a pity for the machine, it’s scary to say how much I invested in it: (Ask questions, maybe I didn’t take something into account in my story. I’ll try to answer. Maybe someone I know has come across this. I’m really looking forward to advice. Of course, I’ll write about it if I can (and have enough money) solve it this problem.
They are also called valve seals. What are these very small parts needed for? Their purpose is to prevent oil from leaking from the cylinder head into the working cylinders through the valve stem. The design of the product is a steel bushing “wrapped” in rubber with a twisted spring. Today, acrylate rubber is used to make valve seals - a durable and reliable artificial material.
Timely replacement of valve stem seals prevents increased oil consumption and falling performance characteristics engine caused by mixing the air-fuel mixture and lubricant.
Why are valve stem seals needed and how do they work?
The valve reciprocates due to direct contact with camshaft Timing belt When it spins, an oil mist is created. In this case, the valve periodically enters the combustion chamber area, where the presence of a lubricant is unacceptable. Valve seals remove oil from the valve stem without allowing it to enter the cylinder block.
Over time, they age: the rubber loses its elasticity, the parts become hard and the lubricating fluid begins to leak into the combustion chamber. To avoid excessive wear of the oil seals, they must be replaced in time.
Signs of worn valve seals
If you manage to recognize the failure of these parts in time, you will be able to avoid more serious damage engine (cylinder-piston group parts). Main symptoms:
- Thick smoke with a white or bluish tint is visible from the muffler pipe: it appears for a short time when starting the engine.
- The concentration of smoke increases when you sharply press the accelerator pedal or change gears.
- Consumption lubricant increases noticeably (more than 1 liter per 1000 km).
- The spark plugs are oily and have black carbon deposits. This is due to the fact that when creating in the combustion chamber high pressure Oil particles are literally squeezed out through micro-gaps (0.3 mm is enough) in the spark plug threads and traces of lubricant consumables are visible even around the screwed-in spark plug.
Wear on the valve stem seals cannot be avoided: these components of the gas distribution mechanism operate in increased load. In just one minute, the valve manages to make 150-1200 “stroke” (cycles). Plus, the products are exposed to an aggressive environment: exhaust gases.
The question arises, when to change valve stem seals? If you bought a new car, then you need to do this after about 50-70 thousand kilometers (on imported cars, the mileage can be 180 thousand km or more).
If you ignore the above signs of oil seal wear, you should expect problems with the engine, namely:
- reduction in power (the car will pull worse) due to poor performance of oily spark plugs;
- “floating” speed at idle;
- When the speed drops, the engine may stall.
It is also worth paying attention to dynamic characteristics car - for example, acceleration and fuel consumption. If these two parameters have not changed, then we can speak with a high degree of confidence about wear of the valve seals. The same is indicated by normal compression in the engine cylinders.
Replacing valve stem seals
The duration and complexity of this process depends on the make of the car and the specific model. But general principles replacements can be outlined. To successfully replace valve stem seals without removing the head, you must:
- Cool the engine completely and remove the valve cover.
- Make sure the marks on the pulley, distribution and crankshaft.
- Loosen the drive and remove the camshaft.
- “Dry” the valve springs (it is better to use a puller).
- Using pliers or a special collet, remove the valve seals.
- Take new products and lubricate their inner surface motor oil. The same needs to be done with their seat.
- Place the valve seals onto the stem and press them in using gentle blows with a rubber hammer.
- Put the springs back and “dry” them.
If there are suspicions that the valve stem seals have not been changed for a long time, you will have to remove the cylinder head and clean the elements of the cylinder-piston group from carbon deposits.
Replacing caps on a VAZ 2121 (16 valves)
It is best to carry out this operation on removed head cylinder block. But if this cannot be done, you can replace the valve seals with your own hands on the spot. You need to prepare in advance:
When everything is ready, you can proceed directly to the process. The algorithm of actions is as follows:
- Disconnect the positive terminal from battery, remove the high-voltage wires and unscrew the spark plugs.
- Set the top dead center as you do when changing the timing belt (the marks on the camshaft, pulley, and crankshaft must match).
- Take a 12 mm socket wrench and remove the valve cover.
- Pull out the plugs connected to the blocks.
- Remove the ignition coil.
- Remove the throttle (if it is dirty, take the opportunity to clean it).
- Remove the valve cover and remove the screws that secure the rocker arms (pull them out too).
- Take the compressor and “dry” the valves, first wrapping the device in a rag so that the valve retainers do not fly apart in different directions. One part of this device is stationary, and the other presses on the valve plate, simultaneously compressing the spring and releasing the “crackers”.
- If the valve goes into the combustion chamber when a tool is applied to it, then a wooden block or similar device will have to be inserted into the spark plug hole to stop the valve.
- Remove the worn oil seals from the bushings and press on new ones. Reassemble in reverse order.
It is worth taking seriously the choice of valve stem seals for the VAZ2112. Experts recommend the following kits:
- 2112-1007026: these are original products produced by AvtoVAZ and installed on the conveyor - ideal for Russian cars;
- setMaster-sport;
- Herzog;
- Trialli;
- STD "Reserve";
- Goetze: It’s worth taking a closer look at this manufacturer. Most experts prefer these products, despite the more high cost. The fact is that valve seals from this company are easier to install (the risk of damage is minimized) and they last longer even than the original VAZ ones.
When purchasing oil seals for a foreign car, you need to take into account the design of the caps. For example, on Japanese products there is a protrusion inside that matches the corresponding groove on the sleeve.
It is clear that such valve seals cannot be installed on European, American or Russian cars. It is worth noting that removing and installing valve stem seals with your own hands will cost less, even taking into account the purchase of a desiccant, than a trip to a car service center. If it is not possible to immediately replace the valve stem seals, then you can try to delay the inevitable repairs by using special additives. They are able to temporarily seal the gaps between the valve and its seal. Car chemicals of this kind will be cheaper than replacing caps (even on your own): it allows you to continue to use the car for some time. The most commonly used additives include:
- Wagner (USA);
- Liqui Moly (Germany);
- "Lavr" (Russia).
Why you shouldn't drive with worn valve seals
When lubricant enters the combustion chamber, fuel and lubricants are mixed, as a result of which the oil begins to turn into a combustion product and settle on the electrodes of the spark plugs in the form of black soot. As a result, sparking becomes unstable, the engine operates unstable and does not develop full power. Contaminated spark plugs will sooner or later lead to failure of one of the cylinders. Another impending problem is burnout of one or more valves. This is also fraught with cylinder failure and a sharp increase in oil consumption.
