Oil in antifreeze - unpleasant consequences for the engine. Oil in antifreeze - the reasons for getting into the cooling system How to find out that oil is being added to the expansion tank

Car owners are often faced with the problem of hitting engine oil into the cooling system of the car. Oil in antifreeze is a bad sign, such a mixing of oil and antifreeze is unacceptable. Inside the car, their movement takes place along independent sealed and isolated systems.

Why is this happening

Signs are different: damage to the oil cooler or a malfunction of the cylinder head. The contact between the cooling and oil systems occurs only at these points. Some cars need to maintain a specific oil temperature from seventy-five to eighty-five degrees. Such vehicles are equipped with an oil cooler that interacts with the cooling system, and the coolant is antifreeze.

Oil in antifreeze indicates that it will be necessary to sort out the oil cooler and fix the problem, or you will have to change everything completely. Lubricating properties are lost, there is a heavy load on the engine, which eventually fails. The composition of antifreeze contains glycol with toxic indications, therefore, when it enters the engine lubricant, the potential is destroyed. This leads to blocking of oil molecules and lubricating properties.

Causes and solutions to the problem:

• the block head gasket is punctured - remove the head and replace the gasket;
• deformation of the plane of the head - grinding (milling work);
• poor tightening of the bolts - tighten with a torque wrench;
• microcrack in the cylinder block - seal with epoxy paste, clean the surface, weld, weld steel.

The reason for the oil getting into the antifreeze is the gasket burned out or the block head itself is faulty. This problem comes up when drivers start checking the fluid level. The color and density of the coolant changes, the coolant has a pungent odor... This is the “first call” for the driver of the car.

Ethylene glycol is used today as the basis for coolants. It is diluted with water in certain proportions, but has a toxicity disadvantage.

Lower boiling point, but better quality for propylene glycol fluids, although their production requires more costs.

If the system is depressurized or the pipes are damaged, the engine fluid instantly appears in the cooling system and vice versa. There are many factors behind this problem. One of the most important is the mismatch of the refrigerants used by the vehicle driver.

Defining the problem

It can be quite difficult to determine exactly why the oil gets into the antifreeze. Basically, this problem is identified by white smoke from exhaust pipe... The quality of the oil is of great importance. If the oil dipstick has a white coating, this indicates the presence of this problem. The best way out for drivers is, of course, to turn to specialists.... A special luminous additive is used to identify the problem. It helps to identify the exact locations of cracks, leaks and other imperfections. When the problem is not solved in this way, there is a gradual disassembly of the entire cooling system and some engine parts. All parts are diagnosed for all kinds of breakdowns and malfunctions.

After detecting oil in antifreeze, you need to determine the cause of its appearance, do testing and eliminate this deficiency. In order to prevent oil from getting into the antifreeze, it is necessary to regularly monitor the liquid level, color and its condition. When a breakdown is detected, it saves on repairs and minimizes all the consequences. Sometimes the situation can still be saved by independently replacing the gasket, pressing and grinding the cylinder head, as well as replacing the valve stem seals.

What can happen:

• decrease in the throughput of filters;
• the formation of beads with ethylene glycol and oil;
• the formation of acids that cause chemical destruction, corrosion;
• decrease in antifriction properties;
• worn out bearings.

The ingress of oil into the coolant is associated with the cylinder block. An experienced motorist immediately determines that this is a burnout of the gasket.

Consequence - change in color and saturation exhaust gases, decreasing the level of the coolant liquid in the distribution tank.

The above information suggests that there are few reasons for oil getting into the antifreeze. Though the consequences can be disastrous for the vehicle engine... It is necessary to carry out a visual inspection of parts and regular maintenance of the vehicle every day. Don't ignore the problem and the alarms from the insides of your vehicle. The slightest defects and breakdowns must be eliminated immediately by contacting specialized service centers or at a service station.

As you know, any modern engine internal combustion requires good lubrication of those parts that experience friction, as well as high-quality cooling, which ensures timely removal of excess heat. For this, the motors are equipped with oil and antifreeze systems, and they are arranged in such a way that the liquids circulating through them do not mix.

Nevertheless, it often happens that when checking the level of the coolant, motorists find a serious change in its consistency and color. This suggests that grease has got into it, and the problem requires an early solution. In order to eliminate it, first it is necessary to establish exactly why the oil gets into the antifreeze.

The lubrication and cooling systems of internal combustion engines are not only unconnected in any way, but also sealed. Therefore, if it is found that there is still oil in the coolant, then it is quite logical to assume that it got there due to depressurization. In practice, this is how it happens in the overwhelming majority of cases, but the immediate reasons for hitting lubricating fluid in the coolant fluid are:

• Cylinder head malfunctions;
• Pump worn out;
• Cracked heat exchanger gasket;
• Cracked expansion tank;
• Oil cooler problems;
• Failure of branch pipes of the cooling system or lubrication system.

Since there are channels in the cylinder head through which the coolant flows, due to microcracks that appear in it as a result of impacts or for other reasons, the oil can easily penetrate into the antifreeze. The deterioration of the pump manifests itself, among other things, in its depressurization, which can also lead to the ingress of lubricant into its interior. Cracks in the gasket of the heat exchanger, oil cooler and expansion tank also serve as places for the "expansion" of oil outward, as well as failure of the pipes of the cooling and lubrication systems.

How to identify antifreeze in oil

Oil in antifreeze

As mentioned above, most motorists find that oil has got into the antifreeze when they check the coolant level. However, there are other symptoms that such impermissible confusion has occurred. One of them is that when the antifreeze is drained, the last few milliliters of it turn out to be too dark, they have a thicker consistency and it is not so easy to drain them from the tank. The fact is that since oil and antifreeze have different indicators of viscosity and density, they do not mix with each other. The lubricating fluid is lighter, it floats to the top and therefore flows out last.

Another sign that antifreeze is grease is that it becomes flammable. It is very simple to check this: you need to soak a regular paper towel in antifreeze and try to set it on fire. If this succeeds, then oil has got into the antifreeze, since it does not burn by itself. It goes without saying that, when conducting such an experiment, you need to move a considerable distance from the car.

Quite often, the fact that oil has got into the antifreeze can be determined by the condition of the oil filter. It breaks down faster than usual, its capacity decreases, and the car begins to experience "oil hunger". The fact is that when antifreeze enters the oil, rather dense small balls are formed that "clog" the filter.

Possible consequences of oil getting into antifreeze

If it is found that oil gets into the antifreeze, then this problem must be eliminated as soon as possible, since it can lead to very serious consequences. Since the tightness of the lubrication and cooling systems power unit is broken, then the antifreeze is contaminated with oil, and the oil is contaminated with antifreeze.

Both fluids contain many different additives, most of which are reactive. It is impossible to predict which reactions will occur between them, but it is absolutely unambiguous that they will lead to a significant decrease in the quality of both oil and coolant. As a result, the performance of both the lubrication system and the cooling system is seriously impaired. As practice shows, bearings suffer the most from this, in addition, the risk of engine seizure increases significantly.

It should be noted that the penetration of oil into antifreeze and antifreeze into the oil is most dangerous for diesel power units. The fact is that this leads to corrosion of the cylinder walls, and as a result, when the engine is off and cooling down, sooner or later antifreeze penetrates into the combustion chambers. Further, when the engine is started, the so-called water hammer occurs, the power unit jams and it requires complex, expensive and rather lengthy repairs.

What to do if oil is found in the antifreeze?

In the event that it turns out that oil has got into the antifreeze, it is best to contact a service station. Its specialists will diagnose, determine the exact cause and eliminate it. However, whatever it is, the masters will certainly merge both liquids, since none of them will be able to fully perform their functions.

After that, both the engine cooling system and its lubrication system must be flushed. This is necessary to remove those contaminants that they probably have. In addition, the oil filter is being replaced. In the process of eliminating this problem, it is almost always replaced with a new cylinder head gasket, the pump, thermostat and pipes are thoroughly washed. If it turns out that the heat exchanger is to blame for the mixing of the cooling and lubricating liquid, then it is also washed out. In addition, the oil pump gaskets are replaced.

Thus, the ingress of oil into antifreeze requires a whole range of repair and preventive measures. It is imperative to carry out them in order to avoid the occurrence of truly serious problems with the engine.

Video on the topic

Engine oil and coolant, with the correct operation of all vehicle units, should not intersect. They circulate in vicious circles, each doing their job. But if some elements fail, the driver may, during the next check of the antifreeze level, find that there are traces of oil in the tank. Oil getting into antifreeze is not a normal situation for a car. If a similar problem occurs, you need to find out what it is associated with, and then fix it.

How to determine if oil has got into antifreeze

More often than not, drivers find out late that oil gets into antifreeze in their car. At the same time, the problems due to which the liquids circulating in closed circles mix are very significant. For example, such a problem can be observed due to damage to the cylinder head gasket or due to depressurization in the area of ​​the heat exchanger gasket. Also, oil in antifreeze may indicate that the oil cooler is damaged and needs to be urgently replaced or repaired.

The following symptoms indicate that oil particles are present in the antifreeze:

It is worth remembering that not only oil enters the antifreeze, but also, conversely, coolant particles flow into the lubricating element. This leads to the fact that, together with the oil, small particles of antifreeze are sent into circulation in a circle, which can accelerate the formation of corrosion on the engine elements. Also, due to mixing of liquids, the oil will partially lose its properties.

What to do if oil gets into antifreeze

If coolant and engine oil mix, act immediately after detecting a problem. Most often it is associated with wear or damage to the oil cooler gasket. It is not possible to restore the sealing element, therefore, it needs to be replaced.

To replace the oil cooler gasket, do the following:

If replacing the oil cooler gasket did not help and oil continues to get into the antifreeze, you can try or contact the service center.

The penetration of engine oil into the coolant in a car is a fairly common phenomenon. If you find such a problem, you need to contact a specialist to fix it.

The devices, through which the two components pass - oil and coolant, are completely sealed and independent of each other, therefore the presence of oil particles in the cooling system is not the norm. Wherein Special attention need to be reversed, if there is oil in the cooling system of the diesel engine, find out the reasons.

First signs of engine oil and coolant leakage

Vehicle owners, periodically servicing their car, may encounter some problems, indicating the fact that liquid is leaking in the car. These include:

• the presence of dense smoke;
• if the color of the engine fluid or cooling element has changed;
• when checking the cylinder liners, their curvature was found;
• the volume of the coolant has decreased;
• on oil filter clots are observed;
• there was a rather unpleasant smell in the coolant.

If such signs are found, then you need to find the reason for the engine oil getting into the cooling elements.

Why does oil get into the engine coolant?

After detecting the first signs of a leak, it is necessary to determine the problem that led the corresponding devices of the car to such a state. For the presence of oil in the cooling system car engine the following reasons affect:

• there is mechanical damage in the radiator or oil cooler;
• The cylinder block or oil cooler gasket is worn out and loses its elasticity or is cracked.

The cooling system and the oil cooler are completely sealed, but their constituent elements (hoses, pipes) are in contact with each other. In places of friction of hoses and gaskets of systems, cracks may occur, as a result of which the engine fluid immediately enters the cooling system of the vehicle or vice versa.

A separate reason for the ingress of oil into the antifreeze should be noted the use of a coolant that is not suitable for a particular vehicle. It is not necessary to add any antifreeze to the required level. Different refrigerant manufacturers use a variety of additives to maintain a protective oxide layer on the cylinder liner.

Using refrigerants with different additives can damage the cooling elements. An insufficient amount of additives in the used refrigerant will lead to acceleration of chemical reactions and deformation of the system, and an excessive amount will increase the likelihood of premature corrosion of the system surface.

Reasons for engine oil entering the diesel engine cooling system

Particular attention should be paid to a diesel car engine. The diesel engine becomes more contaminated when out of service. During the cooling process of a diesel engine, thermal changes in the cylinder head occur, leading to a change in the location of the gaskets and seals. All these are the reasons for the oil getting into the diesel engine cooling radiator and vice versa.

Experienced drivers can correctly determine the cause of the leak. But they sometimes need the help of a specialized service company. In such services, a special luminous liquid is added to the cooling system to locate leaks in the cooling system, which allows you to accurately determine the place of the leak.

But it is not always possible to find cracks or a place of depressurization of the system in this way. In this case, specialists have to disassemble the entire structure and determine the malfunction by elements.

How do you know if engine oil and coolant have mixed?

It is necessary to contact a service company to diagnose a car for an oil leak in antifreeze, if the motorist understands by certain signs that this has happened. So, if in the process of getting rid of the coolant in the car, a rather thick dark liquid is found, the particles of which are on the surface of the coolant, then most likely the oil got into the antifreeze.

If you dip a regular napkin in the particles floating on the surface of the antifreeze and set it on fire, the napkin will burn. The presence of soot particles in the engine oil also indicates a leak. Another problem is possible here, when soot particles get clogged into the filter. This can lead to a complete lack of oil passage through the filter and, consequently, to cylinder failure.

The coolant is based on an alcohol solution, therefore, when oil enters it, a certain chemical reaction takes place with additives of oil and antifreeze. This is subsequently reflected in the purity of important elements of both diesel and gasoline engines.

The most dangerous in diesel engines is the curvature of the walls of the cylinder liner, leading to the ingress of part of the antifreeze into the combustion chamber. As a result, the coolant will not have the required density and the engine will stop.

Replacing the gasket when repairing a leak

To eliminate the leakage of engine oil into the coolant of the car due to a worn out gasket, you need to install a new one. For the replacement procedure, you will need distilled water, a new gasket, and a new coolant.

First, you should rinse the structure with a special cleaning liquid. To do this, you need to pour a cleaning liquid into the cooling structure of the car, turn on the engine for as long as it takes to start the fan. Then it is necessary to empty the system, draining the used antifreeze from it. Antifreeze is drained through a hole behind the engine or radiator plugs.

The oil cooler is being disassembled into its constituent elements. In this case, the car enthusiast should be guided by the server description to vehicle, as the order of disassembly depends on the specific vehicle. After disassembly, the entire system must be thoroughly cleaned and the worn out gaskets must be replaced with new ones. Gaskets should be purchased for a specific vehicle.

After replacing the gasket, the car owner should clean the coolant tank. Alternatively, you can purchase a new tank and replace the old one. After flushing or purchasing, the tank is secured in place. Pour the required amount of distilled water into the tank and turn on the engine.

Keep the engine running until the cooling fan comes on. Stop the engine after running for 10 minutes. Here you can see that as the motor cools down, the fan also turns off. After these manipulations, the motorist needs to drain the distilled water.

Flushing is carried out several times. Pay attention to distilled water that has been poured out. It must not contain particles of engine oil. After flushing the coolant system, you can fill in a new high-quality antifreeze recommended by specialists.

The final stage of the repair of the cooling system

At the end of the procedure, you must turn on the engine and press the gas pedal. At the same time, it is necessary to squeeze the pipes of the vehicle cooling system with the expansion tank cap closed. This procedure will prevent the formation of air in the cooling system. Therefore, one person cannot cope with the process; an assistant is required.

When using the car in the future, you should periodically open the expansion tank to release air jams.

The basic rule for a motorist is to keep the engine clean. To less often contact service companies, you need to go through in a timely manner Maintenance, check the quantity and quality of oil in the system, regularly change engine oil and coolant.

Oil in antifreeze most often appears due to a punctured cylinder head gasket (cylinder head), as well as damage to the elements of the cooling system, excessive wear of the heat exchanger gasket and some other reasons that we will consider in detail. If oil gets into antifreeze, then the solution to the problem cannot be postponed, since this can lead to serious problems in the operation of the car's power unit.

Signs of oil getting into antifreeze

There are a number typical signs, by which you can understand that engine oil gets into the coolant (). Regardless of how much lubricant gets into the antifreeze, the signs listed below will indicate a problem that needs to be solved as quickly as possible in order to prevent serious and expensive repairs to the car engine.

So, signs of oil leaving antifreeze include:

• Change in color and consistency of the coolant. Normal working antifreeze is a clear, blue, yellow, red, or green liquid. Its darkening for natural reasons takes a long time, and is usually comparable to a routine replacement of the coolant. Accordingly, if the antifreeze darkens ahead of time, and even more so, its consistency has become thicker, with impurities of fat / oil, then this indicates that the oil has gone into antifreeze.

• On the surface of the antifreeze in expansion tank the engine cooling system has a greasy film. It is visible to the naked eye. Usually the film has a dark tint and reflects light rays well in different colors (diffraction effect).
• The coolant will feel oily to the touch. To convince yourself of this, you can drop a small amount of antifreeze on your fingers and rub them between your fingers. Pure antifreeze will never be oily; on the contrary, it will evaporate quickly enough from the surface. The oil, if it is included in the antifreeze, will be clearly felt on the skin.
• Changes in the smell of antifreeze. Typically, the coolant is odorless or has a sweet scent. If oil gets into it, then the liquid will have an unpleasant burning smell. And the more oil in it, the more unpleasant and distinct the aroma will be.
• Frequent. Due to the fact that the oil reduces the performance of antifreeze, the latter is not able to cool the engine normally. This also reduces the boiling point of the coolant. Because of this, a situation is possible when antifreeze will be "squeezed out" from under the radiator cap or the cap of the expansion tank of the cooling system. This is especially true for engine operation during the hot season (summer). Often, when the engine overheats, its uneven operation is observed (it "troit").
• Oil stains are visible on the walls of the expansion tank of the cooling system.
• On the caps of the expansion tank of the cooling system and / or on the radiator cap, oil deposits are possible on the inside, and an emulsion of oil and antifreeze will be visible from above under the cap.
• As the engine speed rises, air bubbles emerge from the fluid in the expansion tank. This indicates a depressurization of the system.

The above information is summarized in the table below.

Thus, if the car owner encounters at least one of the above signs, then it makes sense to perform additional diagnostics, check the condition of the antifreeze, and, accordingly, start looking for the reasons that led to the presented situation.

Reasons for getting oil into antifreeze

Why does oil go into antifreeze? In fact, there are a number of typical reasons why this malfunction occurs. And in order to understand why exactly the oil went into antifreeze, it is necessary to perform additional diagnostics of the state of individual engine elements.

Let's list the typical causes from the most common to the rather rare:

• ... It can be either natural wear and tear, or an incorrect tightening torque during installation (ideally, tighten with a torque wrench), misalignment during installation, an incorrect size and / or gasket material, or if the motor overheats.
• Damage to the cylinder head plane. For example, a microcrack, sink or other damage may occur between its body and the gasket. In turn, the reason for this may be hidden in mechanical damage to the cylinder head (or the engine as a whole), head misalignment. It is also possible the occurrence of foci of corrosion on the cylinder head housing.

• Worn gasket or failure of the heat exchanger itself (another name is oil cooler). Accordingly, the problem is relevant for machines equipped with this device. The gasket can leak from old age or improper installation. As for the heat exchanger body, it can also fail (a small hole or crack appears in it) due to mechanical damage, aging, and corrosion. As a rule, a crack occurs on the pipe, and since the oil pressure at this point will be higher than the antifreeze pressure, the lubricating fluid will also enter the cooling system.
• Crack in the cylinder liner. In particular, from the outside. So, as a result of engine operation, oil entering the cylinder under pressure through a microcrack can flow in small doses into the coolant.

In addition to the listed typical reasons, typical for most gasoline and diesel engines some motors have their own design features, due to which oil may leak into antifreeze and vice versa.

One of these engines is a 1.7-liter Opel diesel under the designation Y17DT manufactured by Isuzu. In particular, in these engines, the injectors are located under the cylinder head cover and are installed in cups, the outside of which is washed by the coolant. However, the sealing of the glasses is provided by rings made of an elastic material that dulls and cracks over time. Accordingly, as a result, the degree of sealing decreases, which makes it possible that the oil and antifreeze will mix together.

In the same engines, cases are occasionally recorded when, as a result of corrosion damage to the glasses, small holes or microcracks appeared in their walls. This leads to similar mixing consequences for the mentioned process fluids.

The above reasons are summarized in the table.

Consequences of oil getting into antifreeze

Many, especially beginners, motorists are interested in the question of whether it is possible to drive when the oil has got into the antifreeze. In this case, it all depends on how much oil got into the coolant. Ideally, even with the slightest leakage of lubricant into antifreeze, you need to get to a car service or garage, where you can carry out repair work yourself or seek help from the masters. However, if the amount of oil in the coolant is small, you can still drive a short distance by car.

It must be understood that oil not only reduces the performance of antifreeze (which leads to a decrease in engine cooling efficiency), but also harms the overall cooling system. Also, often in the event of such emergencies, not only oil enters the coolant, but also vice versa. And this can already lead to significant problems during the operation of the engine itself. Therefore, when the above problem is identified, the repair work must be carried out as quickly as possible, since their delay is fraught with the occurrence of more serious breakdowns and, accordingly, expensive repairs. This is especially true for machine operation in hot weather (summer), when the operation of the engine cooling system is critical for the power unit!

As a result of the operation of a coolant that contains engine oil, the following troubles may arise with the car engine:

• Frequent overheating of the motor, especially when operating the machine in hot weather and / or running the engine on high revs(high loads).
• Clogging of the cooling system elements (hoses, pipes, radiator elements) with oil, which reduces their efficiency to a critical level.
• Damage to the elements of the cooling system, which are made of non-oil-resistant rubber and plastic.
• Reducing the resource not only of the engine cooling system itself, but of the entire motor as a whole, since with a faulty cooling system, it practically starts to work for wear or in a mode close to this.
• In the event that not only oil enters the antifreeze, but also vice versa (antifreeze flows into the oil), this leads to a decrease in the efficiency of lubrication of the internal engine parts, their protection from wear and overheating. Naturally, this also negatively affects the operation of the motor and the period of its normal operation. In critical cases, the engine can partially or even completely fail.

Thus, it is better to start repair work as early as possible in order to minimize the negative effect of the lubricating fluid not only on the cooling system, but also to prevent negative effects on the vehicle engine as a whole.

What to do if oil gets into antifreeze

The performance of certain repair work depends on the reason for the appearance of oil in the antifreeze tank and, in general, in the cooling system.

• Damage to the cylinder head gasket is the most common and easily solved problem if there is engine oil in antifreeze. There is only one solution - replacing the gasket with a new one. This procedure can be performed independently, or by contacting the masters at a car service for help. At the same time, it is important to choose a gasket of the correct shape and with the appropriate geometric dimensions. And it is necessary to tighten the fastening bolts, firstly, in a certain sequence (the diagram is indicated in the technical documentation for the car), and secondly, using a torque wrench in order to strictly withstand the recommended tightening torques.
• If the cylinder head is damaged (its lower plane), then two options are possible. The first (more labor-intensive) is to grind it on the appropriate machine. In some cases, the crack can be repaired with high-temperature epoxy resins, chamfering, grinding the surface with a grinding wheel (on a machine). The second way is to completely replace the cylinder head with a new one.
• If there is a microcrack on the cylinder liner, then this is a rather complicated case. So, to eliminate this malfunction, you need to contact a car service for help, where there are appropriate machines with which you can try to restore the cylinder block to work. In particular, the block is bored and new sleeves are installed. However, the whole block is often changed.
• If there are problems with the heat exchanger or its gasket, then it is necessary to dismantle it. If the problem is in the gasket, then it must be replaced. The oil cooler itself is depressurized - you can try to solder it or replace it with a new one. Before installation, the repaired heat exchanger must be flushed with distilled water or special means. However, in most cases, the repair of the heat exchanger is not possible due to the very small size of the crack and the complexity of the structure of the device. Therefore, it is changed to a new one. The heat exchanger check can be done with an air compressor. To do this, one of the holes (inlet or outlet) is muffled, and the air line from the compressor is connected to the second. After that, the heat exchanger is placed in a tank with warm (important !!!, heated up to about +90 degrees Celsius) water. Under such conditions, the aluminum from which the heat exchanger is made expands, and air bubbles will come out of the crack (if any).

When the cause of the breakdown is found out and eliminated, do not forget that it is imperative to replace the antifreeze, as well as perform it. It must be carried out according to the standard algorithm and using special or improvised means. If there was a mutual exchange of fluids, and antifreeze also got into the engine oil, then it is necessary to change the oil with preliminary cleaning of the engine oil system.

How to flush the emulsion from the cooling system

Flushing the cooling system after engine oil has got into it is a mandatory measure and if you neglect the flushing of the emulsion, but only fill in fresh antifreeze, this will greatly affect its service lines and functioning.

Before flushing, old, spoiled antifreeze must be drained from the system. Instead, you can use special factory products for flushing cooling systems or the so-called folk. In the latter case, it is best to use citric acid or milk whey. An aqueous solution based on these funds is poured into the cooling system and several tens of kilometers are rolled. Recipes for their use are given in the material "". After flushing, new antifreeze must be poured into the cooling system.

Conclusion

It is possible to use a car with oil in its cooling system only in the most extreme cases, for example, to get to a car service. Repair work must be performed as early as possible with the identification of the cause and its elimination. The use of a car in which there is a mutual mixing of engine oil and coolant in the long term is fraught with very difficult and expensive repairs. So if you notice oil in the antifreeze, sound the alarm and get ready to spend.