Any engine internal combustion needs to high-quality lubricant and cooling - it is these systems that determine how long the heart of the car will work - its power unit, which is exposed to extreme loads. The working substance in both the cooling system and the lubrication system are technical fluids, which are fundamentally different in their characteristics. Therefore, their circulation lines in the engine do not intersect, which prevents their mixing and loss operational properties. To ensure this mode of operation, the designers had to work hard, but overall this system works very well. Provided everything is in order. But the reality is that any mechanical device Sooner or later . Since a modern car engine consists of thousands of parts, assemblies and assemblies, the likelihood that over time one of them will fail increases as the vehicle ages.

Failure of certain components power plant can lead to the sealing of the cooling system being broken, in which case the antifreeze begins to leak. In certain cases, such a leak can lead to its entry into the lubrication system.

We will tell you in what cases this happens, what threatens the engine, and how to detect and fix the problem in time.

Reasons for coolant getting into engine oil

Before we begin to study the question of how to diagnose a malfunction and what to do to fix it, let’s consider the main reasons for antifreeze getting into the engine oil. This will, to a certain extent, help us correctly localize the breakdown in order to make the right decision on how to minimize the consequences for power unit.

In principle, there are few such reasons:

• loss of integrity of the gasket separating the two main parts of the motor: the upper (block head) and the lower (the block itself). In a particular case, the coolant will not flow out at all in case of such a malfunction, that is, when the antifreeze level drops visual inspection engine parts and subsystems will be unsuccessful. We have already said that the line through which antifreeze circulates is closed, separate and sealed. But since the motor consists of two parts, and its internal geometry is quite complex, there is at least one large joint (between the BC and the cylinder head), which can be considered a potential source of depressurization of the cooling system. Initially, between these halves a moderately soft gasket is installed (made either from thin sheet metal or from paronite with reinforcement and a metal edging around the perimeter), which does not allow mutual penetration technical fluids, nor their flow out. Damage to this gasket is one of the main reasons for depressurization of the cooling circuit, and in this case, antifreeze will enter the working cylinders - the responsibility of the engine oil. the reasons for damage to the gasket can be different, from burnout (due to the slightest inaccuracies when installing the gasket) to violation of the ideally flat geometry of the seat;
• the occurrence of defects in the block head. As a rule, such deformations occur mainly in the area directly adjacent to the lower part of the power unit, that is, to the cylinder block. The consequences of such defects are predictable - deterioration of the tightness of the seal to the seating planes of the gasket. At the same time, even without being damaged, it will gradually begin to leak coolant (due to its much lower viscosity than engine oil). In this case, there will definitely be no external signs of a leak, so if you find an antifreeze leak, you will definitely not be able to quickly localize the place where it is leaking. If the curvature of the seat is minimal, there will be very little leakage and the mixing of fluids will also be gradual. This is bad, because the consequences of such a mixture of oil and antifreeze will last much longer, and we will talk about them later. Such a malfunction can only be determined by troubleshooting, that is, after disassembling the cylinder head;
• Another reason why antifreeze gets into the oil is the occurrence of defects in the cylinder block body itself. These could be cracks located in areas of coolant circulation, which again occur when the engine overheats or as a result of a collision of the car with an obstacle. This malfunction is considered the most serious, since identifying it will require dismantling the entire engine.

Symptoms of coolant in oil

For the reasons given above, it is most often not possible to notice in time the loss of tightness of the cooling system in the cylinder head/cylinder head area. At the same time, problems leading to mixing of two technical fluids circulating through separate lines can be very serious. An example is the depressurization of CO in the area of ​​the heat exchanger gasket or the already mentioned leak due to a breakdown of the cylinder head gasket. In some cases, we can talk about, which also leads to mixing antifreeze and MM.

We list the main signs that allow you to determine how antifreeze gets into engine oil:

• if, during the procedure for replacing antifreeze, you find that when draining is completed, liquid flows noticeably more dark color- we can assume that this is a lubricating fluid that has a lower density and therefore rises to the upper part of the radiator. Of course, the consistency of the liquid also changes, and so much so that it flows out of drain hole hardly. That is, in a calm state, these technical fluids do not mix. Having different viscosity/density indicators, they behave differently, which is easy to notice if you are observant and unaware of possible trouble;
• Another common way to determine whether antifreeze has gotten into the oil is using matches or a lighter. The fact is that antifreeze is in pure form does not burn (although it contains ethylene glycol, it is diluted with water in a non-flammable consistency). But if motor oil gets into it, such a liquid can already be set on fire. This is what this method is based on. We take an ordinary paper napkin, dip it in antifreeze and try to burn it. If there is oil in the coolant, the piece of paper will certainly burst into flames; if the antifreeze is clean, nothing will happen. Since this method is a fire hazard, all requirements must be observed when using it. fire safety and carry out this procedure at a considerable distance from the car;
• although much lower, this does not mean that mixing always occurs unilaterally when antifreeze enters the MM. Sometimes the opposite situation occurs when oil penetrates the cooling system. In this case, depressurization can also be determined by color: the lubricating fluid should darken. This is especially noticeable if it has been changed relatively recently (old oil darkens for natural reasons - due to contamination);
• One of the simplest and most obvious ways to determine the presence of antifreeze in oil is to monitor fluid levels. If the expansion tank gradually becomes empty, and oil dipstick the level, on the contrary, increases - it’s easy to understand what’s happening. Especially if there are no visible signs of antifreeze leakage;
• When coolant enters the cylinders, it mixes with exhaust gases, passing into a gaseous state. The color of the exhaust will change to light (normally it is almost transparent) - this is the result of the presence of water vapor in the exhaust. In winter, this is not an obvious sign of CO depressurization, since moisture enters the exhaust pipe from the air, but in summer such a symptom is difficult to miss;
• a sure sign of mixing technical fluids is the presence of a whitish emulsion that appears in the area of ​​the oil filler neck, with a consistency reminiscent of whipped cream - this is the result of coolant getting into the lubricating fluid;
• You can see if antifreeze gets into the oil by unscrewing the spark plugs. If the electrodes are wet, sniff them. The characteristic smell of antifreeze is a clear indication that coolant is entering the combustion chamber;
• finally, deterioration in the performance of the power unit and the appearance of tripping is another potential symptom of oil contamination with antifreeze. True, not very reliable - many other malfunctions lead to the same result.

What to do if oil is mixed with antifreeze

Many car owners, having learned about the presence of a problem, do not always rush to fix it, believing that it is not serious enough to take urgent action. Of course, this opinion is wrong, and we will tell you why. Our advice is not to hesitate, start repairs immediately after detecting depressurization of the cooling system and antifreeze getting into the engine oil.

If the cause of the malfunction lies in the depressurization of the oil cooler gasket (in this case, oil gets into the antifreeze), it must be replaced. This is done in the following sequence:

• First of all, you should flush the cooling system line to get rid of any remaining lubricant. This procedure is performed using a special solution, which can be purchased at any auto store. The product is poured into the coolant reservoir;
• For high-quality washing we start the engine and let it run for 5, maximum 10 minutes - this should be enough to warm up the engine to operating temperature. This can be recognized by the fan turning on. We turn off the power unit;
• drain the flushing liquid;
• install an empty container under the car in the radiator area, unscrew drain plug and wait until all the coolant has flowed out;
• Now you can begin dismantling the oil cooler. It is impossible to give specific advice here, since this element of the engine design is different models removed and installed differently. How to do this can be found in the user manual;
• After dismantling the oil cooler, it can be disassembled and inspected, after which it can be thoroughly rinsed and cleaned. Worn seals should be removed, their seating area should be cleaned, and new gaskets should be installed, which must be purchased in advance for a specific car model;
• the next step is to dismantle the expansion tank and clean it. You should make sure that there are no significant defects on the body - otherwise it is better to replace the tank with a new one;
• We install the oil cooler and expansion tank in place and again flush the system with distilled water. To do this, pour it into the cooling system and start the engine, completely turning off the air flow into the cabin and using the maximum possible number of on-board electrical consumers (this will speed up the warming up of the power unit). As soon as the fan turns on, you should turn off all electrical appliances and activate the interior airflow. After about 10 minutes, the motor should cool down and the fan should turn off. We turn off the engine and wait until the distilled water cools down so that it can be drained;
• repeat the flushing procedure with distilled water again, drain it and fill in with fresh antifreeze;
• Finally, you need to try to get rid of air pockets, for which you will need an assistant. Start the engine and put him behind the wheel while you go to engine compartment. Ask a friend several times, without skimping, to “gas” it, and at this time begin to squeeze the CO pipe with the expansion tank cap closed. After this, open the cap so that the air accumulated in the tank comes out.

If after replacing the oil cooler gasket the problem does not go away, antifreeze most likely gets into the oil through a damaged cylinder head gasket.

Let's start replacing it (algorithm for VAZ-2109):

• dismantle the air filter housing;
• disconnect all the wires going to the engine, as well as the fuel supply hose;
• pour the coolant into a pre-prepared container;
• unscrew the manifold mounting bolts;
• disconnect the explosive wires;
• all we did was dismantle the so-called attachments, which will interfere with the removal of the cylinder head. To unscrew the GB itself, you need a hex wrench and a fairly thick wrench. You need to unscrew 10 bolts along with washers, then very carefully you can begin to remove the head by pulling it vertically up. It is important here to avoid distortions, so as not to bend the studs. A broken gasket can either remain on the block or stick to the seating surface of the head - it doesn’t matter. If it cannot be removed by hand, you should use a flat-head screwdriver, but be very careful not to leave scratches - these could become a source of future problems;
• We carry out a visual inspection of the head for signs of corrosion - if there are any, you need to get rid of the rust by performing milling/grinding procedures if necessary;
• clean the remains of the old gasket, degrease seat;
• carefully install the new gasket, making sure that it coincides with the guides located at the corners of the BC;
• We also carefully put the head in place, and during docking with the block, make sure that the gasket does not move;
• We tighten the bolts with the obligatory use of a torque wrench, first with a force of up to 25 Nm, then tighten them sequentially to 85, 120 and 140 Nm;
• we install back the attachments;
• We start the engine, warm it up and only after that we take a test drive.

Don’t forget that if antifreeze gets into the oil, the power unit needs to be washed. First, the cooling system is washed with a special solution (we described how this is done a little higher), then - oil channels with fresh filling lubricating fluid. This is a mandatory procedure to get rid of residual mixed technical fluids.

Consequences of oil contamination with antifreeze for the engine

The coolant is a mixture of alcohol and distilled water. If such liquid gets into the engine oil, it is quite obvious that the lubricating properties of the latter will deteriorate as a result of dilution with antifreeze. The longer this mixing lasts, the worse the MM will lubricate the rubbing parts of the power unit.

It is not difficult to predict that the consequences of antifreeze getting into the oil will be far from optimistic: accelerated wear of engine parts will lead to the need for premature engine overhaul, which is complex and expensive. If for owners of cars with high mileage and the age of the “capital” - it’s fashionable to say, a routine operation, then the need to restore a fairly fresh engine can turn out to be a very unpleasant surprise for the car owner.

Now let's move on to specifics.

If there is a depressurization of the cooling system, in which coolant penetrates into the cylinders, and the driver did not notice this (which is quite likely), then with further operation of the car, quite soon clearly audible knocking noises will begin to be heard in the engine area. This is the result of wear and tear.

The mechanism for the occurrence of knocking is as follows:

If antifreeze begins to leak from the oil through the cylinders, the first to feel the deterioration in the lubrication properties of the MM are the liners, which are essentially slightly modified, highly loaded plain bearings. They are available both at the distribution and at crankshaft power unit. Poor quality lubrication will lead to the formation of inner surface liners are scuffed, which will only increase over time. They are the source of bearing knocking.

If you disassemble the engine and remove the liners, you will find that the friction layer on their surface is practically absent, but there are enough deep scratches and scuffing (bulges). Due to overheating, the color of the liner changes from gray to mottled brown.

If you continue to examine the surface of the bearings under a microscope, which provides a very high (thousand-fold) magnification, you will notice microscopic white balls with diameters of about 25-35 microns on the surface of the bearings. It is these particles that are responsible for the formation of scratches: when high speed rotation of the shafts they. Like a plow, they bite into the surface of the bearings, leaving grooves and burrs of appropriate sizes.

With such aggressive behavior, the friction layer’s chances of remaining unharmed tend to zero. You may ask, where did these balls come from, since at first they were not there? Let's figure it out.

According to spectrographic studies, these round abrasive particles consist of a mixture of sulfur, phosphorus, calcium and other elements. Although it is not a metal, the hardness of these particles is higher than that of the friction layer. So he is the one who suffers first. Over time, the balls, which also experience heavy loads, become so compact that they become harder than the material used to make the liners. Then they attack the bearings themselves, destroying their surface.

Where did the particles come from? It turns out that from the additives contained in all modern oils. But the catalyst for their precipitation and grouping into large formations is antifreeze. Plus, of course, high temperature.

A verbal description of this process is not very informative, since we have little idea at what speed all these metamorphoses occur on a running engine, to what temperatures its rubbing parts heat up.

The second most important consequence of mixing oil and antifreeze in the engine can be called, which is facilitated by the active mixing of these two liquids at high speeds. Why is this happening? As we already know, the coolant contains a considerable amount of water. And if oil is practically insoluble in water, then the same cannot be said about additives. This means that by partially dissolving in antifreeze, they reduce their concentration in the lubricating fluid. It is noteworthy that a minimum amount of coolant is required to start such a process.

Let us recall once again that all these processes occur when high temperatures Oh. As they know in chemistry courses, thermal energy promotes the occurrence of various reactions between substances. That is why it does not take much time to form sufficiently strong compounds of phosphorus, sulfur, potassium, and zinc in the oil. The main condition is that antifreeze gets into the MM.

We hope that our readers (or at least part of them) understood the danger of a situation when depressurization of the cooling line occurs, localized in the area of ​​the cylinder head or the very side of the cylinders. And if you don’t want the engine to knock, and this will inevitably happen if you do not act, you should be very careful about such actions recommended by all automakers, such as checking the oil and antifreeze levels daily - this is what will tell you about a potential threat that should not be eliminated hesitating.

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During the next check of the coolant level in the system, you can sometimes detect a strange phenomenon: antifreeze in expansion tank darkened. There may be several reasons for darkening of the coolant.

Firstly, any antifreeze is designed for its limited service life. Often it does not exceed 5 years. After this period, the additives and coolant base begin to degrade. This often causes the antifreeze to change color.

Secondly, rubber, plastic and metal elements, when using low-quality coolant or one not intended for a specific system, they can dissolve under its aggressive influence. Particles of rubber or plastic circulate through the system and float up in the expansion tank, which looks like darkening of the liquid itself.

And thirdly, the cause of darkening may be oil in antifreeze. It is this most unpleasant reason for the change in coolant color that will be discussed in the article.

Why does oil get into the cooling system?

Oil in the coolant expansion tank can appear for several reasons. And each of them indicates serious malfunctions, which must be eliminated as quickly as possible.

Let's look at the main reasons why and how oil gets into antifreeze or any other coolant.

Violation of the integrity of the gasket under the cylinder head (cylinder head)

This malfunction, in turn, can be caused by three reasons.

1. Thermal destruction. Overheating of the engine can burn a corridor in the body of the gasket that connects the circuit of the cooling and lubrication systems. Moreover, for oil to penetrate into antifreeze, and not vice versa, antifreeze into oil, the oil supply channel must be connected to high pressure, that is, coming from the pump. If the drain oil circuit is connected to the liquid circuit, the coolant will begin to flow into the oil. It's all about the pressure difference.
2. Caused by engine overheating. But here the cylinder head is already deformed. The mating surfaces are no longer plane-parallel to each other, and the gasket between the head and the block no longer ensures tightness. The lines of the lubrication and cooling systems are connected.
3. Destruction of the gasket over time. If the motor is more than 10 years old, then cylinder head gasket During this period it may simply decompose. Under the influence of high temperatures, pressure and time, the gasket material degrades with all the ensuing consequences.

Crack in the cylinder head or cylinder block

This is also a common malfunction leading to oil penetration into the antifreeze. Stresses in the metal of the cylinder head and cylinder block, with the assistance of temperature, pressure, vibration and other mechanical influences, sometimes develop into cracks.

Diagnosing such a malfunction is not always easy, and often it is confirmed with one hundred percent probability only after complete disassembly of the internal combustion engine. It is classified as irremovable. If a crack has formed, you will have to replace the cylinder block or head.

Heat exchanger damage

Some cars use a heat exchanger to maintain the temperature of the automatic transmission or variator oil in the operating range. This is an effective solution. The engine, warming up to operating temperature, is much faster than the box gears, heats the oil in the automatic transmission through a heat exchanger with antifreeze.

In the same way, the coolant removes heat from the gearbox oil when it warms up above operating temperature. If the tightness of the heat exchanger circuits is broken, automatic transmission oil may enter the cooling system line.

Oil entering the cooling system circuit during repair work

For example, when the cylinder head is removed, oil may partially enter the cylinder block jacket. If oil gets into antifreeze, the negative consequences will appear quite quickly. First, the heat dissipation efficiency will decrease.

This will affect the operating temperature of the engine. Over time, the coolant can turn into an emulsion, which will lead to clogging of the cooling system and radiator lines. The pump may fail. As a result, it will only be a matter of time before the engine overheats and fails.

How to solve a problem

First of all, it is necessary to find out the reason for the appearance of oil in antifreeze. If the lubricant has penetrated into the cooling system line through a crack, then there is nothing special to advise car enthusiasts.

In any case, the engine will have to be overhauled by replacing the damaged element. Or search and install new motor, which often turns out to be a more rational option.

Once the cause is found, you will need complete replacement lubricants and antifreeze. This is almost always mandatory. It rarely happens that mixing of working fluids occurs in only one direction. To some extent, antifreeze will penetrate into the oil. And this will lead to a decrease in lubricating properties.

Oil in the coolant leaves a residue on the walls of the radiator, pipes, cooling jackets, as well as the pump and thermostat. This introduces some peculiarities into the troubleshooting procedure.

What you need

Oil getting into the engine cooling system is a very unpleasant problem that will require labor-intensive operations. To properly restore engine performance, regardless of the source of the problem, you will need the following:

In addition to this set, the degree of reverse penetration must be taken into account. Definitely need to drop valve cover and look at the condition of the oil underneath. If there is an emulsion, even in small quantities, we additionally purchase a flushing composition for the engine lubrication system.

With automatic transmission everything is a little more complicated. Here, in the event of abundant water entering the gearbox lubrication system through the heat exchanger, it is advisable to rinse the valve body not with a passing stream, but directly by disassembling it. And these are serious operations that require high qualifications.

Step-by-step instruction

First of all, after identifying the source of the problem, we decide on an action algorithm. There will be one for each case. Of course, the problem itself is eliminated.

If oil appears in the engine cooling system due to a damaged cylinder head gasket or after a repair error, then all old antifreeze is completely drained.

Each car has its own draining algorithm, so you need to know it exactly. The upper part of the expansion tank and its plug are wiped. These are the only areas of the system that are not completely washed by antifreeze.

If oil has entered the system through the oil cooler gasket, the algorithm, list and sequence of actions depend more on the degree of contamination of the lubricant.

If there is a sufficient amount of coolant in the gearbox to form an emulsion, then automatic transmission flushing will be added. If the emulsion is not detected, then the ATF fluid is replaced with a new one. After this, the above algorithm of actions is performed to clean the cooling system.

Bottom line
There are not many reasons for oil getting into the cooling system. But each of them entails a considerable amount of restoration work. And if problems are not corrected in a timely manner, this can lead to serious damage.

Therefore, in order to timely detect oil in the engine cooling system and promptly eliminate this problem, it is necessary to monitor the condition and level of antifreeze in the expansion tank at least 2 times a month.

Learn more about the reasons for the appearance of oil in the coolant and how to eliminate it - video

Sometimes motorists try to check whether the fluid level in the expansion tank is normal, but suddenly they see changes in the color and consistency of the antifreeze. This may also be accompanied by an oily residue remaining on the plug or neck.

Such symptoms indicate the presence of motor oil in the antifreeze, which means the problem requires an immediate solution. Oil and refrigerant are substances of different types and effects; in addition to their different purposes, they also have different effects on vehicle systems. Therefore, the oil and antifreeze circulation systems must be sealed and under no circumstances depend on each other.

The first and most well-known reason for motor lubricant getting into the refrigerant is depressurization of their circulation systems in the car.

There are some problems that lead to this, including:

• oil cooler malfunction;
• cylinder head failure;
• worn out pipes of the engine cooling system;
• failure of the gasket in the heat exchanger;
• presence of cracks in the expansion tank;
• damage to cylinder head liners due to corrosion;
• hydraulic pump failure.

As a result of breakdowns and depressurization in pipes and gaskets, motor lubricant at the same moment the refrigerant begins to penetrate. In some cases, oil penetration may be caused by poor quality coolant that is not suitable this car. To avoid the problem, it is advised not to use antifreeze mixtures and to purchase only high-quality brands.

Consequences of oil leakage into antifreeze

A widely known problem is when the oil cooling system, designed to maintain a constant level of operating oil temperature, breaks down. If the mechanism's pipes are damaged, oil can penetrate through the cracks into the antifreeze.

If you find oily bubbles on the surface of the liquid in the expansion tank or a change in its color, you should immediately check the pipes and, if necessary, replace them with new ones. In this case, you should clean all cooling system, completely replace the antifreeze, as well as the oil. Most likely, this will solve the problem.

Statistical data confirms that at least half of all failures car engines, especially in cases with diesel engines, occurs precisely due to the penetration of oil into antifreeze, or vice versa.

It is worth noting that diesel engines are the most sensitive and very often find themselves inoperative. They are most often damaged due to thermal damage to the cylinder head, as a result of which the seals and gaskets are displaced. Since lubricating and cooling fluids cool under different, but high pressures, they enter each other’s systems through the cracks that form.

Sometimes cavitation damages the liners, which can also cause two fluids to mix. Cavitation leads to chemical and mechanical damage and occurs due to vibration inside the motor and adjacent systems. This vibration is caused by the movement of the pistons, and protective film, formed on the walls of the sleeve sometimes does not withstand it.

Molybdenum, phosphate and sodium nitrite additives as coolant additives help provide this protection by imparting coolant antioxidant properties. Their excess or deficiency leads, respectively, to corrosion or chemical damage.

What threatens the engine as a result of mixing oil with antifreeze?

The main component of antifreeze is active alcohol. It also contains water. Together they are insoluble in mineral environments and contaminate important engine parts. Lubricant and coolant additives, when reacting, lead to the appearance of new compounds that have destructive or neutral properties, but at the same time precipitate.

The corrosion that occurs after these reactions jams all mechanisms, entering them as a result of the formation of black soot deposits. Soot can be identified by changes in the color of engine parts.

Also, after mixing, the oil filter may become clogged. When changing oil and antifreeze, it is very important to completely clean the system. It is worth remembering that about 10% of the oil remains in the engine after draining, so you need to completely clean the system with by special means, otherwise additives fresh oil accelerate the unwanted effect and further damage the engine.

» Antifreeze gets into the oil: possible reasons and their elimination

A car engine has a lubrication and cooling system. These are two irreplaceable components of any internal combustion engine. These systems use different fluids, which during normal engine operation should not intersect with each other. However, if any element fails, oil appears in the antifreeze. The reasons may vary. Well, let's take a closer look at this problem.

Signs

If antifreeze gets into the oil, how can you tell? There are several signs to look out for:

• Coolant level. On a serviceable engine, it should not be changed during operation. However, if the level decreases, albeit slightly, this may indicate that antifreeze is getting into the engine oil.
• Traffic fumes. The exhaust becomes whiter and thicker. When the engine operates, a specific steam is generated. But you need to understand that such a phenomenon is considered normal in severe frost. However, if the temperature outside the window is above zero, this a clear sign that antifreeze gets into the oil.
• Candles. The electrodes of the spark plugs will be filled with antifreeze and will emit a characteristic odor.
• Oil. If antifreeze gets in, it changes its color and structure. Usually the oil turns almost white.
• Emulsion on the oil filler neck. It may resemble a thick “mayonnaise”.

About the white coating on candles

If formed white coating on spark plugs, the reasons may be different. First of all, this indicates problems with fuel quality. But if it is a rough white coating on the spark plugs, the reasons are due to overheating of the engine. Also, similar soot forms if:

• The candle does not fit this engine(by heat number or other parameters).
• The inlet pipe is leaking. Here air will be taken in from outside.
• Poor ignition calibration.
• There are problems with the cooling system (for example, a faulty radiator).

Why does coolant seep into the oil?

Experts identify several reasons for this phenomenon:

• Deformation of the gasket that separates the block and cylinder head. This is the answer to the question of where the antifreeze goes if it doesn’t leak anywhere. The internal combustion engine has separate channels for coolant. But their isolation is incomplete due to the presence of breaks at the junction of the block and the cylinder head. To ensure a seal, a gasket is installed. This also prevents oil leakage. But if the cylinder head gasket is broken (the symptom is an emulsion in the oil), then antifreeze will penetrate the lubrication system. The element breaks due to burnout. Also, if the cylinder head gasket is blown, the symptoms will be as follows: a drop in coolant level and a characteristic White smoke from the exhaust.
• Defects on the cylinder head. The key role here is not played by the head itself, but rather by the area adjacent to the cylinder block. If there is deformation in one of the areas, the tightness of the gasket will deteriorate. Even if the latter is not damaged, due to insufficient sealing, antifreeze enters the oil. This problem is complicated by the fact that it cannot be noticed immediately. Where does antifreeze go if it doesn’t leak anywhere? It is mixed in small quantities with oil. And head deformation can be detected only after troubleshooting. This requires a specialized tool. The head is placed on the edge and the evenness is determined with a metal ruler. If a defect is detected, the head is ground.
• Defects in the block body. This applies to sections of channels where antifreeze circulates. This problem is the most serious, since the engine has to be removed from the car.

What to do if coolant gets into the oil?

So, having determined the cause of the problem, you can begin repairs. The easiest option is to replace the head gasket. But this is only done if it burns out. To do this, the cylinder head is removed, the area is cleared of the old gasket, a new one is installed and the bolts are tightened to the appropriate torque. As practice shows, antifreeze no longer gets into the oil. In this case, repair costs will be minimal.

But the most difficult stage in the work is the removal and subsequent installation of the cylinder head. IN in this case You will need a torque wrench. The bolts must be tightened in accordance with the diagram (usually crosswise). The tightening torque is individual for each vehicle.

It would be useful to troubleshoot the head. If there are imperfections on the surface, sanding will be required. But it is performed only on specialized equipment. You can’t do this without the help of a master. If the head is “sick” (for example, due to severe overheating), then grinding may not help. In such a situation, you only need to install a new head. The same goes for the block. If there are cracks on it, the block needs to be replaced.

How to change the gasket?

Let's consider the replacement procedure using the example of a VAZ-2109 car. To do this we need:

• Remove the air filter housing.
• Disconnect all fuel supply hoses and power cables.
• Drain the coolant.
• Unscrew the manifold.
• Disconnect the high-voltage wires.

In this way, we free the head from everything unnecessary, so that nothing gets in the way when removing. To unscrew the head itself, you need a powerful wrench and a hexagon. A total of ten bolts need to be unscrewed. The latter are removed along with the washers. Next, the head carefully rises up. It is important not to distort it. The gasket itself may remain on the head or stick to the block. You can remove it with your own hands or pry it off with a minus screwdriver. The surface of the cylinder head is inspected for corrosion. If there is rust, it will need to be milled and sanded. If all is well, you need to remove traces of the old gasket. Having cleared the surface of its residues, degrease the area.

What's next?

Install a new gasket. When installing, you need to pay attention to the fact that the gasket coincides with the guides that are on the corners of the block itself. Next, the block head is mounted. It is important that the gasket does not move during this process. Next, tighten the bolts with a torque wrench in three stages:

1. 20-25 Nm.
2. 70-85 Nm.
3. 120 Nm. Afterwards the bolts are tightened with a force of 140 Nm.

At the next stage, all attachments are assembled, and the car will be ready for use. When starting for the first time, you need to warm up the internal combustion engine to operating temperatures, and only after that make the first trip.

Washing features

If antifreeze gets into the oil, you need to understand that the engine will need to flush the systems. The first step is to rinse the circle through which the coolant moves. To do this, you need a special solution, which can be found in auto stores. The product is poured into the expansion tank and the engine is started for 10 minutes. When the fan turns on, you can complete the flushing.

After this, the old antifreeze is drained. Pre-prepare a container with a volume of at least five liters. Next you need to remove the oil cooler (if one is provided in the car). On different cars it is filmed in different ways. After dismantling, you need to thoroughly clean it and install new seals.

Next, the expansion tank is removed. It needs to be washed. Distilled water is poured into the motor and the engine starts. After the engine has warmed up, you need to turn on the interior airflow. The stove should work for about 10 minutes. Then the engine is turned off. Drain the liquid. After this, you can already fill in fresh antifreeze. Sometimes the system produces airlock. To remove it, you need to open the expansion tank cap and squeeze the SOD pipe.

Please note that flushing the system is carried out after installing the new gasket. At the same time, the oil also changes.

Consequences of driving with a broken gasket

It is prohibited to operate a vehicle where antifreeze gets into the oil. What is the reason? The liquid itself, despite its toxicity, does not harm the engine. But the danger is posed by ethylene glycol, which is contained in the coolant. If it mixes with oil, it creates abrasive particles. Because of this, there is a risk of scoring.

What happens when antifreeze gets into the cylinder block? Then it interacts with the oil, and deposits are formed in the form of an emulsion. This leads to a decrease in the diameter of the channels. Lubricant and antifreeze are not able to circulate normally. As a result, the motor runs with insufficient pressure oil and overheats. The oil filter also becomes significantly dirty.

The oil itself, diluted with coolant, loses its lubricating and protective properties. This reduces engine resource and faces high repair costs.

Let's sum it up

So, we found out why antifreeze gets into the oil. As practice has shown, this problem can be identified in time by the car owner. The main features are the characteristic white exhaust and a drop in the level of antifreeze in the tank. If liquid penetrates oil, the latter changes its structure. This is determined by the probe. In addition, suspicions may be reinforced by the wet electrode on the spark plugs and the characteristic sweet smell of antifreeze on them. We looked at the reasons for antifreeze in oil. Should not be used further similar car. This type of engine overheats easily. In addition, it will work with bad oil, which has lost all its positive properties. The cost of repairs will depend on the nature of the problem. This could be a gasket, head or block. In the latter case, the cost of rebuilding the engine will be the most significant.

Antifreeze in engine oil may be due to various reasons - failure of the cylinder head gasket, damage to the plane of the cylinder head, damage to the heat exchanger, etc. However, in any case, the result of the antifreeze going into the oil will be very unpleasant consequences, consisting in the fact that the normal process of lubrication of individual engine parts will be disrupted with all the ensuing consequences.

Likewise, if oil penetrates into the antifreeze, the function of the engine cooling system will be disrupted. Accordingly, if the above malfunctions are detected, it is necessary to carry out diagnostics as quickly as possible and renovation work in order to minimize their negative impact and prevent costly repairs.

How to determine antifreeze in oil

Many, especially novice, car enthusiasts are interested in the question of how to find out that antifreeze has entered the oil system of the car’s engine. In fact, there are a number of typical signs by the presence of which one can judge the occurrence of this malfunction. Among them:

• An emulsion appears on the neck under the cap. made directly from oil and antifreeze, usually white or yellowish in color, similar in appearance to cream (sour cream, mayonnaise). Accordingly, the more antifreeze or antifreeze that has leaked into the oil system, the more such a mixture will be in its composition. It is not difficult to check the presence of an emulsion; to do this, you just need to look at the condition of the engine oil on the dipstick. There will be a similar emulsion on the oil filler neck, just open the cap.
• Coolant level drop. This sign is indirect, since antifreeze can leave the system not into the oil, but simply into engine compartment. Therefore, in this case, additional diagnostics are necessary.

• Engine overheating. This symptom is also indirect, since it can be caused by other problems. However, if antifreeze and oil are mixed, then, accordingly, the cooling and lubrication systems will stop working normally, which will also lead to rapid overheating of the engine, especially when it operates at significant loads (speeds).
• Presence of oil in antifreeze. As a rule, when one (or both) systems depressurizes, mutual mixing of these process fluids occurs. At the same time, the antifreeze turns black and begins to smell like burnt oil, and the cooling system does not work well. You can look at the condition of the antifreeze by opening the cap of the expansion tank of the cooling system.
• Engine power drop. This factor is a logical result of the deterioration of the cooling and lubrication systems. Often the motor “troits”. Additional diagnostics must be performed as other problems may be causing the loss of power.
• White smoke from the exhaust pipe. This is true for both gasoline and diesel engines, however, the reasons why this phenomenon is caused differ in the first and second cases. If white smoke comes out of the exhaust system, then there is antifreeze in the engine elements. For gasoline engines Coolant enters the cylinders, and in diesel engines it enters the manifold.
• Spark plugs will have a light tint(color of burnt antifreeze). True, this is only an indirect sign; a number of other reasons will need to be considered.
• Air bubbles in the expansion tank cooling systems. They can be seen through the transparent tank body or by opening the cap (at high engine speeds). The higher they are, the more air will leave the system. This sign directly indicates depressurization of the system.
• Coolant leaks from under the cylinder head gasket on the body of the block itself. At the same time, regardless of their color, it is necessary to check the condition of the engine oil and antifreeze in the engine to ensure they are mixed with each other.

If a car owner encounters one or more of the symptoms listed above, then it makes sense to check the condition of the engine oil, coolant, and also perform additional diagnostics of individual engine parts, which will be discussed below.

Causes of antifreeze in oil

There are a number typical faults, through which the engine oil and coolant are mixed in the internal combustion engine. Among them:

• Cylinder head gasket burnout. According to statistics, this reason is, firstly, the most common, and secondly, the easiest to eliminate. Burnout of the gasket can be caused by various factors, in particular: overheating of the engine, which causes the head to “drive”, incorrectly selected tightening torque of the fixing bolts, natural aging of the material from which the gasket is made. The described breakdown can be repaired by the car owner himself if he has the appropriate tools. As for financial costs, you will only have to spend money on a new gasket.
• Violation of cylinder head geometry. Another popular name is “moved its head.” Most often, this malfunction occurs as a result of significant overheating of the engine, and is more typical for engines that are small in both power and size (for example, city runabouts).
• Heat exchanger failure(oil cooler) and/or its gaskets.
• Damage to the cylinder block. Occasionally (usually as a result of damage or defects) there are microcracks on the block liners, which leads to mixing of oil and antifreeze. Here we can also note such a phenomenon as corrosion of cylinder liners.
• To throttle valve. This is a fairly rare reason, but it occasionally occurs on used cars, whose previous owners or craftsmen incorrectly connected the mentioned cooling system pipes. In this case, the antifreeze goes directly into the engine oil, and from there into exhaust system(collector and beyond).

For clarity, the reasons listed above and brief information Methods for eliminating them are summarized in the table.

Cause	Troubleshooting methods
Cylinder head gasket burnout	Replace the broken gasket with a new one. It is important to observe both the tightening torque value and the sequence of tightening the bolts.
Violation of cylinder head geometry	Crimping, milling, grinding of the head. Performed in specialized workshops. Checking its tightness.
Failure of the heat exchanger and/or its gasket	Replacing the gasket, repairing or replacing the heat exchanger.
Damage to the cylinder block	Repairing the unit in a car service center or replacing it with a new one.
Corrosion of sleeves	Boring or replacing sleeves with new ones.
Incorrect cooling system connection	Revision of the connection diagram. The problem is often relevant for cars purchased secondhand.

It is interesting that many novice car enthusiasts confuse slightly frozen oil during frosts and the antifreeze emulsion itself. It is important to understand that when the machine is idle for a long time in the winter with significant frosts, the oil thickens and may take on a yellowish tint. Therefore, it is necessary to perform additional diagnostics with a warm engine in order to find out what the car owner is dealing with - frozen oil or emulsion.

Antifreeze in oil consequences

If you do not attach due importance and do not fulfill timely repairs car engine, then the reasons why antifreeze gets into the oil can not only significantly reduce engine performance, but also lead to complex and expensive repairs. In particular, this is due to the following factors:

• Reduced efficiency of lubrication and cooling systems. So, if the oil contains coolant, the lubrication efficiency will sharply decrease with all the ensuing consequences. That is, this will lead to excessive wear of the engine’s rubbing parts (which the oil is designed to protect). On the other hand, antifreeze can also be mixed with oil. This will have two consequences. The first is that the coolant will also lose its performance characteristics(heat capacity and its boiling point decrease). Second - decrease general level antifreeze in the cooling system, which in itself reduces its efficiency.
• If there is deformation of the cylinder head, a situation may arise where problems arise with the pistons and rings. In particular, scuffing may appear on the piston body (several pistons) (due to overheating and changes in geometry). As for the rings, compression and oil scraper rings(occurrence of rings).
• General reduction in engine efficiency. This is expressed in loss of power, unstable operation of the motor, it can “sneeze” and “triple”. In any case, operating the car in this condition is extremely undesirable, since it is not only harmful to the engine, but also unsafe from the point of view of driving on the road.

Many car enthusiasts are interested in the question of whether it is possible to drive a car when there is antifreeze in the oil? Ideally, the answer is simple - you can’t! However, in practice, everything depends on the amount of antifreeze in the oil, the availability of a workshop, as well as general condition engine and the machine as a whole. So, if the mixing is minor, then you can drive a car to a garage or service station, where the repair work can be carried out directly. However, in the long term, using the machine is definitely not possible! This can lead to very complex and expensive repairs.

What to do if there is antifreeze in the oil

What action should you take if antifreeze is mixed with engine oil? The answer to this question depends on the reason that caused this malfunction. We list the actions in the same order in which the above reasons were listed.

• Cylinder head gasket failure. In this case, it is necessary to replace the gasket itself. To do this, you need to dismantle the block head. During installation, it is important to be careful to carefully place the gasket in its seat. The second important nuance is that it is very advisable to use a torque wrench when tightening the mounting bolts. Do not tighten them “by eye”, since there is a high risk of exceeding the tightening torque, which will lead to damage to the gasket and premature exit it is out of order. The value of the clamping torques and the bolt tightening sequence are given in the repair manuals for the specific car model.
• Violation of the geometry of the block head. In particular, as a result of overheating or other mechanical damage, the cylinder head can occasionally “lead”, that is, its lower plane is deformed. The solution to this problem is to grind the head on special machines, in particular, crimping and/or milling (grinding). This should only be done in specialized workshops. After carrying out repair work, it is necessary to check its tightness (presence of cracks).
• Damage to the heat exchanger and/or its gasket. Most often it is the gasket that fails due to its normal wear and tear. The only solution in this case is to replace this element. If it is the heat exchanger that is damaged, you can try to repair it (solder it), but this is not always possible. Accordingly, if it cannot be repaired, it should be replaced with a new one.
• Incorrect connection of the cooling system line. In this case, it makes sense to check the correct connection of the pipes, as well as the gaskets (in particular, the manifold gasket).
• Damage to the cylinder block. This is a rather complicated case, and to eliminate the malfunction you need to dismantle the unit. Repair work is carried out at a car service center, where the block is bored out and new liners are installed into it. In the very difficult case The entire cylinder block is replaced.
• Extraneous leaks. In some cases, antifreeze leaks occur on the pipes and/or at various connections. For example, on a temperature sensor (in particular, relevant for some Opel models, on the liquid supply tube to the stove). It is better to diagnose such leaks when the engine is running at high speeds, since in such conditions antifreeze leaks out at excess pressure, which means it’s easier to notice the location of the leak.

Regardless of the reason for which the antifreeze got into the oil (or vice versa), after eliminating the causes and performing the appropriate repairs, it is necessary to also replace the coolant. Before that, flush the cooling system and engine.

How to flush the engine when antifreeze gets into the oil

You need to start flushing the engine by removing old oil from it, which contains some amount of antifreeze. Then fill in a special one instead flushing oil. U different manufacturers There are similar compositions, so it makes no sense to advertise them. Or simply take several cans of the cheapest motor oil (you will still have to drain it after 100 km), you can also take the most affordable oil filter. So change the oil several times and therefore fill in the new oil required for the engine, and do not forget to install a new good oil filter.

Often when flushing oil system to remove the emulsion, use special oil system flushes or even diesel fuel (it works well with condensed milk from oil and liquid). But after such a product, you should still use flushing oil.

Conclusion

Mixing antifreeze and engine oil causes significant negative consequences for the engine, especially in the long term. Therefore, when this phenomenon is detected, it is necessary to find out the cause as quickly as possible and carry out the appropriate repair work. The most common cause of antifreeze and oil mixing is a blown cylinder head gasket. It is quite possible to change it yourself. To perform more complex repairs It is advisable to seek help from specialized auto repair shops.