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Why is the thread on the spark plug wet? Oil on candles: causes and solutions. Cleaning the crankcase ventilation system

The quality of operation of the power unit largely depends. Therefore, the appearance of problems in their operation can lead not only to incorrect operation of the motor, but also to the impossibility of starting it as a whole. What does the oil on the spark plug thread mean, the reasons for the appearance of engine fluid and what to do in such cases - read in this article.

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Causes of the problem

The appearance of oil on the spark plugs is accompanied by engine vibration during the first time after starting, as well as a bluish tint of the exhaust gases. When the engine warms up, these symptoms disappear. With such a problem, the power unit will consume more lubricant; these symptoms indicate incorrect temperature in the engine cylinders. The appearance of oily soot indicates that the heating value SZ is too high.

The problem may be due to wear on the oil seals, piston rings or valve liners. The pistons or cylinders could be worn out; if the crankcase ventilation system is clogged, excess lubricant will enter the combustion chamber.

The layer of soot on the SZ may vary depending on the degree of neglect of the power unit. Usually the problem lies in the valve stem seals, if carbon deposits appear on the top of the threads, and if at the bottom or on the electrode, then the piston rings are to blame. Such problems are accompanied by a decrease in engine power, an increase in gasoline consumption, difficult starting, and unstable engine idle speed.

If there is a layer of lubricant on the SZ with the remains of unburned fuel, this indicates the inoperability of the cylinder as a result of wear of the valve or the partition between the rings. In this case, the internal combustion engine will constantly triple, and gasoline consumption may double.

Sometimes it happens that a dismantled SZ has neither an electrode nor an insulator - this is a consequence:

  • regular engine operation with detonation;
  • use of low quality fuel;
  • factory defects;
  • incorrect ignition setting.

If this is the case, then the “best” option for the car owner would be if the remains of the insulator and electrode get into the exhaust system without getting stuck or remaining between the seat and the valve. Otherwise, you will have to carry out repairs or completely replace the cylinder head. To accurately identify the cause of the problem, it is necessary to manufacture the motor. If the situation is not advanced, perhaps decoking the piston rings will solve the problem; sometimes it is advisable to clean the crankcase ventilation system. In the worst case scenario, the engine will have to be overhauled.

How to fix the problem?

To ensure normal operation of the motor, there are several options to avoid the problem. Let's look at each of them.

Cleaning the crankcase ventilation system

The procedure is demonstrated using the example of a Lada Granta car:

  1. It is necessary to loosen the clamp and disconnect the crankcase ventilation system pipe from the air supply line. Disconnect the second end of the pipe from the fitting located on the cylinder head cover; the hose can then be removed. Carry out the dismantling of the small branch pipe in the same way; to do this, you need to disconnect it from the cylinder head and the fitting of the injection module. At this stage, you need to disconnect the supply pipe of the ventilation system, disconnecting it from the BC and cylinder head fittings.
  2. All pipes must be washed with kerosene or fuel, then blown with air and dried. It would be a good idea to clean the fitting holes.
  3. Remove the cylinder head cover.
  4. Unscrew the screws securing the oil separator device on the inside of the cylinder head cover and remove the washers. The oil separator housing must be removed.
  5. Then all the screens are removed from the cylinder head and must be washed with kerosene along with the cylinder head cover and the oil separating element.
  6. All system components are assembled in reverse order.

Engine decarbonization

For candles that are filled with oil, there are not many options for solving the problem. You can try to decarbonize the power unit, which is done as follows:

  1. High-voltage cables are dismantled and all protective equipment is removed. At this stage, it is advisable to remember their location. After this, unscrew the high-voltage cables from the reels.
  2. The consumables are drained from the motor and the drain plug is put in place. A special decarbonizing agent must be poured into the engine. The best option would be to decarbonize all cylinders of the internal combustion engine.
  3. After this, the SZ must be slightly tightened, this will prevent the evaporation of the product. So the car should be left for 6-12 hours, depending on what is written in the instructions for use of the cleaner. After waiting the appropriate time, unscrew the lock, but do it carefully, otherwise the cleaner, along with carbon residues, may splash throughout the engine compartment.
  4. Afterwards, the drain plug is unscrewed and all consumables are drained along with the remaining carbon deposits. You can pour oil into the engine and spin it on the starter for 10 seconds; this must be done without installed SZ and a connected coil. Such actions will prevent water hammer when starting the internal combustion engine. When you are sure that there is no more carbon deposits in the cylinders, the SZ must be screwed into place.

View 7 messages - from 1 to 7 (out of 7 total)

    Messages

    Hi all. Became the owner of a Lacetti 2009, 1.6, automatic, 118 thousand. I've driven 3000 km, managed to overhaul the zero rack, replace all filters, oils, timing belt with pump. In the mornings I noticed during the factory that it twitches for 30-40 seconds, and not immediately, but after 15-20 seconds from the factory... I thought there was moisture on the high-voltage wires, I checked everything was dry. I pulled out the spark plugs, the insulation and electrodes were dry, and the threads in oil, closer to the electrodes, were dry, before that I looked into the spark plug wells with a flashlight and couldn’t see anything. The electrodes themselves are excellent: light gray coating... I replaced the Denso k20tt spark plugs with them, but I kept these ones, in good condition, can anyone tell me what is the reason for the threads being in oil? Pah-pah-pah doesn’t eat oil. But now this thought haunts me???? Sincerely, Vladimir!

    I like 0

    Hello! If it doesn’t consume oil, and the electrodes are clean and without traces of oil, then I advise you to plug it in and not worry about it. For as long as I can remember, this carving has been in oil. And the same thing happened on Lanos. Thank God he doesn’t eat butter either.

    Twitching after the factory is also sometimes present and also not immediately. I think this may be how the transition to lambda mixture formation manifests itself. At the moment of starting, the engine works according to the table until the lambda warms up, and then switches to lambda and until it adjusts, it shakes a little

    I like 1+

    I also have oil. It doesn't eat much oil, but the valve cover gasket is leaking with varying degrees of success. I decided for myself that this was a small accumulation of emulsion in the wells. It’s quite small, and when the spark plugs are unscrewed, it naturally seeps down and gets onto the threads.

    I like 0

    And I noticed a little oil on my threads. At the service, by the way, I asked about this. The answer was this: it doesn’t eat oil, the compression is normal and the same, so don’t bother. Well, I don’t bother. Although they write on the Internet that it’s the valve stem seals that need to be changed. And they say this with complete confidence.

    But I don’t want to go there, because the oil and gasoline consumption is adequate, the car drives well and there are no other problems. What else is needed? Right?

    I like 0

    Vladimir, did I understand correctly that after the factory the car “troubles” (or very similar to that), and when it warms up a little, everything is fine? And does this manifest itself especially actively in humid weather or in winter? If this is the case, then I advise you to try cleaning the injectors with ultrasound. In this case, it is highly advisable (due to the removal of injectors) to buy O-rings for them in advance (2 pieces for each injector). It lasted me six months. True, then it started again, but my mileage will be more impressive. I cleaned it at about 150 thousand, at 185 - 190 it began to “tweak” again. I think it's time to change them.

    I like 0

One way to assess the proper functioning of the power plant is to check the condition of the spark plugs. Any disruption of the processes taking place in the cylinders will immediately leave marks on these elements. In most cases, spark plugs provide insight into the operation of the ignition and power systems. But there are also symptoms indicating problems with other components of the power plant.

One such sign is the detection of oil traces on the spark plugs. Lubricant on the spark plugs can appear due to a number of specific malfunctions. Some of them do not pose any particular danger to the engine, but others are a signal of serious problems that can lead to expensive repairs.

Causes of oil on spark plugs

If the candles are covered with oil, then first of all it is necessary to determine exactly which part has the most of it. Many car owners are faced with a situation where only the threads and body are coated with lubricant, while the electrodes are dry and have a normal color (light brown). But it also happens that the entire base ends up in oil.

At the same time, in addition to traces of lubricant, it also manifests itself in other ways with the engine - deterioration in dynamics, increased exhaust smoke, and oil burn. In order for it not to be the cause, it must be eliminated.

Most often, the appearance of grease marks occurs due to wear and damage:

  1. Valve guides.
  2. Oil seals.
  3. Valves.
  4. Cylinder head gaskets (cylinder head).
  5. CPG elements (cylinder-piston group).

Traces of lubricant on the body and threads are mentioned for good reason, since oil can get onto the spark plug not only from the cylinder, but also due to external leaks. So, on some cars, a loose fit of the cylinder head cover gasket is considered a “disease”. As a result, candles seep through leaks and get into the wells. Thus, oil accumulates in the wells of the spark plugs and when unscrewing the spark plugs, both the body and the threads are simply smeared in the accumulated lubricant. The problem is “treated” by replacing the gasket and coating it with sealant.

It is much worse if oil is found in the lower part of the thread on the skirt (while the rest of the candle is clean). This indicates a malfunction of the elements installed in the cylinder head - valves and related elements.

Valve guide with seal

So, oil may appear due to wear on the valve guides. As a result, a gap appears between the guide and the valve, through which the lubricant flows down and enters the cylinders, where it partially settles on surfaces, including the spark plug skirt.

Valve stem seals

Lubricant can also get into the cylinders due to worn oil seals. Due to aging and tanning of rubber, jumping off of the pressure spring and cracks, these elements are simply not able to hold the lubricant, and it gets into the cylinders.

Burning and scuffing on the valve plates and their seats also gives this result, since this causes the tightness of the combustion chamber to be compromised.

Oil on the spark plugs may appear due to a breakdown of the cylinder head gasket, but only in one case - if it connects the oil channel with the cylinder. But it also happens that a breakdown occurs between the cylinder and the channel of the cooling system. In this case, the removed spark plug often looks like new (the coolant washes the base) and there are traces of liquid on it.

Grease on the base and electrodes usually indicates problems with the rings. Due to their severe wear and entrapment, they are no longer able to remove lubricant from the cylinder walls, and it enters the combustion chamber.

There are also more specific reasons, but they are much less common. Such, for example, are an excessive amount of lubricant and a clogged breather (engine ventilation duct). In both cases, excess pressure causes oil to break through the rings into the combustion chamber.

Video: Attention!!! Oil in the cylinder!!! Impact on SPARK PLUGS!

Consequences of a malfunction

If you ignore the problem of lubricant getting into the cylinders, which is indicated by traces of oil on the spark plug, the consequences will be very serious. The lubricant is not able to completely burn out in the cylinders, moreover, the part of it that does burn out becomes the cause of a large amount of soot.

This carbon deposits on the internal surfaces of the cylinder, which affects the processes taking place inside it, and also leads to the occurrence of rings. Because of this, the amount of oil entering the combustion chamber increases sharply. As a result, the engine power drops significantly, and it begins to intensively consume lubricant and fuel. Restoring the engine after this is quite difficult and financially expensive, since a major overhaul is required.

Video: Oil in spark plug wells, ICE 3S FE, eliminating the cause!

What can be done

If the spark plugs are filled with oil, then identifying the cause is not so difficult, but eliminating it can be a troublesome task.

If we talk about the case of a leaking valve cover gasket described above, then everything is very simple - oil is noticed in the spark plug wells - sealing element.

It’s worse if grease is found on the bottom of the spark plug (and it can be on one, several or all spark plugs).

A compression test will partially help here. If the rings are stuck or the valves do not fit tightly, it will certainly decrease. If there are traces of lubricant on the spark plugs, but the compression is fine or even increased (which happens due to the oil present in the combustion chamber, which acts as a seal in the existing gaps), you will have to disassemble the cylinder head to assess the condition of the oil seals and valve guides. In general, it is the last two elements that are the most common reasons for lubricant getting into the cylinders, including spark plugs.

Do not forget that the engine itself has a certain resource. If it is noticed that all the spark plugs are in oil, and the compression has dropped significantly below normal, it may be worth considering a major overhaul, since the degree of engine wear has reached critical levels.

A fairly common phenomenon is the appearance of oil on the spark plugs, which negatively affects the operation of the engine, ranging from unstable starting to a decrease in dynamics, fuel consumption and a general decrease in the power of the power plant.

In addition, the waste of motor oil can increase quite significantly, which, as is known, is more expensive than gasoline and significantly “hits” the pockets of car enthusiasts, plus a constant and unstable engine cannot but stress the owner.

What are the reasons for the appearance of oil on candles? In this article, we will analyze the main ways oil gets into the engine combustion chamber and, as a result, onto the spark plugs.

Possible reasons for oily spark plugs:

2. Valve seals;

4. Piston rings;

5. Increased oil level in the engine crankcase;

6. Crankcase ventilation duct clogged.

1. When the inner surface of the guides wears out, a large gap appears between the valve stem and the guide sleeve, which allows oil from the cylinder head to enter the combustion chamber and onto the spark plugs.

Rarely, but there is also a situation when the guide sleeve comes out of the head body. This usually happens if the bushings have been replaced several times and instead of repair bushings (with an increased outer diameter), standard bushings were installed.

2. Valve seals can leak oil into the combustion chamber for several reasons.

It could be:

“Tanning” of the crimping part of the oil seals, which usually occurs when the engine overheats;

The crimp spring has stretched or jumped off the oil seal body;

The oil seal has risen from the guide bushing body;

When the bushings are heavily worn, the valve works with pressure on one side, pressing the edge of the oil seal, which allows oil to get into the combustion chamber and onto the spark plugs. Therefore, there is no point in replacing valve seals if there is significant wear on the valve bushings or valve stems, since the seals will quickly fail. The valve guides must be replaced immediately.

Signs that they are worn out are the presence of oil at the beginning of the spark plug thread near the spark plug ring, as well as a smoky exhaust when starting the engine, which disappears as the engine warms up.

3. Valves are also subject to wear, especially in this case the valve stems. When they wear out, a large gap appears between the guide and the valve stem, which also leads to oil leakage into the combustion chamber and onto the spark plugs. Replacement of valves and, as a rule, guide bushings is required.

4. When the piston rings, as well as the cylinder bore, wear out, oil is sucked into the combustion chamber, this is the so-called pumping effect. Replacement is required, and possibly the pistons themselves when they are worn out. In such cases, cracked partitions under the rings on the piston are also possible.

Signs of piston ring wear are the presence of oil at the end of the spark plug threads and on the insulators themselves. It is necessary to check the engine cylinders with all spark plugs turned out.

5. An increased oil level can be caused by a banal overflow of oil during replacement, or when coolant gets into the engine sump. It is treated by draining excess oil, or by repairing the engine if antifreeze gets in.

6. When the crankcase ventilation is clogged, the pressure of the crankcase gases increases, which also causes excess oil to enter the combustion chamber, since the piston rings are unable to cope with the large amount of oil in the cylinder.

Engine detonation may also occur (often when using low-octane and low-quality gasoline), which during long-term operation sometimes ends with the fact that when the spark plug is removed, there are no electrodes or the insulator on it. If you are lucky, these parts of the spark plug will “fly out” into the muffler, otherwise, if they get between the seat and the valve plate, complex and expensive engine repairs will be required.

If oil gets into the combustion chamber and, as a result, misfires are observed in individual cylinders, and if the spark plug is heavily oiled, one of the cylinders may stop working altogether.

When the spark plugs are oiled, the engine starts unstable (sometimes even impossible to start), this is especially critical in winter. In this case, removing the spark plugs and cleaning them can help, but, as a rule, this procedure does not last long, since you need to find and eliminate the cause of the appearance of oil on the spark plugs.

Many car enthusiasts put off solving problems with the appearance of oil on the spark plugs by installing new spark plugs and operate the car until the spark plugs are re-installed. However, this approach has an extremely negative impact on the “well-being” of the engine, since such a situation causes increased wear of both valve seats, valve plates, and the cylinder-piston group, against the backdrop of constant topping up of expensive oil.

Our advice is to take care of the engine, your finances and nerves and, without delay, install and repair the engine malfunction.