Oil in antifreeze

Oil in antifreeze most often appears due to a broken 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 the 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 of typical signs by which it can be understood that oil gets into the coolant (antifreeze or antifreeze). Regardless of how much grease gets into the antifreeze, the signs listed below will indicate a problem that needs to be addressed as quickly as possible in order to prevent serious and costly repairs to the car's internal combustion engine.

So, the signs of oil leaving in 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 the routine replacement of the coolant. Accordingly, if the antifreeze has darkened 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 the antifreeze.

• There is a greasy film on the surface of the antifreeze in the expansion tank of the internal combustion engine cooling system. She 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 quickly evaporate from the surface. Oil, if it is part of 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 overheating of the internal combustion engine. 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, it is also possible that the 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 the operation of internal combustion engines in the hot season (summer). Often, when the internal combustion engine overheats, its uneven operation is observed (it “troits”).
• 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 the radiator cap, oil deposits are possible from the inside, and an emulsion of oil and antifreeze will be visible from under the cap.
• With an increase in the speed of the internal combustion engine in the expansion tank, air bubbles emerging from the liquid are visible. This indicates a depressurization of the system.

The above information is organized in the table below.

Signs of breakage	How to check for a breakdown
Change in color and consistency of the coolant	Visual inspection of coolant
The presence of an oil film on the surface of the coolant	Visual inspection of the coolant. Check for oil stains on the inner walls of the expansion tank of the cooling system
The coolant has become oily	Tactile coolant check. Check the inner surface of the caps of the expansion tank and the radiator of the cooling system
Antifreeze smells like oil	Check coolant by smell
Frequent overheating of the internal combustion engine, squeezing out antifreeze from under the cover of the expansion tank, internal combustion engine “troit”	Check the level of antifreeze in the system, its condition (see previous paragraphs), coolant pressure
Escaping air bubbles from the expansion tank of the cooling system	The higher the operating speed of the internal combustion engine, the more air bubbles. Be that as it may, this indicates a depressurization of the system

so, if a car enthusiast encounters at least one of the above signs, then it is worth making additional diagnostics, checking the condition of the antifreeze, and, accordingly, starting to search for the reasons that led to the presented situation.

Causes of oil getting into antifreeze

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

We list the typical causes from the most common to quite rare:

• Burnt cylinder head gasket. It can be both natural wear and tear, incorrect tightening torque during installation (ideally, it should be tightened with a torque wrench), misalignment during installation, incorrectly selected size and / or gasket material, or if the motor overheats.
• Damage to the cylinder head plane. For example, a microcrack, a 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 internal combustion engine as a whole), head misalignment. it is also possible the occurrence of foci of corrosion on the cylinder head housing.

• Wear of the gasket or failure of the heat exchanger itself (another name is the oil cooler). Accordingly, the problem is relevant for machines equipped with this device. The gasket may leak from old age or incorrect installation. As for the heat exchanger housing, it can also fail (a small hole or crack appears in it) due to mechanical damage, aging, corrosion. usually, a crack appears 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. namely, from the outside. So, as a result of the operation of the internal combustion engine, oil entering the cylinder under pressure through a microcrack can flow in small doses into the coolant.

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

One of these ICEs is a 1,7-liter diesel engine for an Opel car under the designation Y17DT manufactured by Isuzu. namely, in these internal combustion engines, the nozzles are located under the cylinder head cover and are installed in glasses, the outer side of which is washed by the coolant. However, the sealing of the glasses is provided by rings made of an elastic material that hardens and cracks over time. Accordingly, as a result of this, the degree of sealing drops, due to which there is a possibility that the oil and antifreeze will be mutually mixed.

In the same ICEs, 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 consequences for the mixing of said process fluids.

The above reasons are systematized in a table.

Causes of oil in antifreeze	Elimination methods
Burnout cylinder head gasket	Replacing the gasket with a new one, tightening the bolts to the correct torque using a torque wrench
Cylinder head plane damage	Grinding the plane of the block head using special machines at a car service
Failure of the heat exchanger (oil cooler) or its gasket	Replacing the gasket with a new one. You can try to solder the heat exchanger, but this is not always possible. In the latter case, you need to change the part to a new one.
Loosening cylinder head bolts	Setting the correct tightening torque with a torque wrench
Crack in the cylinder liner	Cleaning the surface with a grinding wheel, chamfering, sealing with epoxy pastes. At the final stage, the surfacing was made with cast-iron bars. In the most severe case, a complete replacement of the cylinder block

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 antifreeze. In this case, it all depends on how much oil got into the coolant. In the ideal case, even with the slightest leakage of grease into antifreeze, you need to get to a car service or garage, where you can carry out repairs yourself or turn to the craftsmen for help. However, if the amount of oil in the coolant is a little bit, then a short distance on the car can still be driven.

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

As a result of the operation of the coolant, which contains oil, the following troubles with the ICE of the car may occur:

• Frequent overheating of the engine, especially when operating the car in hot weather and / or running the internal combustion engine at high speeds (high loads).
• Clogging of the elements of the cooling system (hoses, pipes, radiator elements) with oil, which reduces the efficiency of their work up 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 internal combustion engine cooling system, but of the entire engine 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 vice versa (antifreeze flows into oil), this leads to a decrease in the efficiency of lubrication of the internal parts of the internal combustion engine, their protection against wear and overheating. Naturally, this also negatively affects the operation of the motor and the period of its normal operation. In critical cases, the internal combustion engine can partially or even completely fail.

so, it is better to start repair work as early as possible in order to minimize the negative impact of the lubricating fluid not only on the cooling system, but also to prevent a negative impact on the internal combustion engine of the car as a whole.

What to do if oil gets into antifreeze

The performance of certain repairs depends on the reason why oil appeared in the antifreeze tank and in the whole cooling system.

• Damage to the cylinder head gasket is the most common and easily solved problem if there is oil in the antifreeze. There is only one solution - replacing the gasket with a new one. You can do this procedure yourself, or by contacting the masters at a car service for help. It is important at the same time to choose a gasket of the correct shape and with the appropriate geometric dimensions. And you need to tighten the mounting 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 maintain the recommended tightening torques.
• If the cylinder head (its lower plane) is damaged, then two options are possible. The first (more labor-intensive) is to machine it on the appropriate machine. In some cases, a crack can be made with high-temperature epoxy resins, chamfered, and the surface cleaned 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 breakdown, you need to seek help from a car service, where the appropriate machines are located, with which you can try to restore the cylinder block to working capacity. namely, the block is bored and new sleeves are installed. However, often the block is changed entirely.
• If there are problems with the heat exchanger or its gasket, then you need to dismantle it. If the problem is in the gasket, then you need to replace it. The oil cooler itself has depressurized - you can try to solder it or replace it with a new one. The repaired heat exchanger must be washed with distilled water or special means before installation. However, in most cases, repair of the heat exchanger is impossible due to the very small size of the crack and the complexity of the design of the device. Therefore, it is replaced with a new one. The heat exchanger can be checked using an air compressor. To do this, one of the holes (inlet or outlet) is jammed, 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 clarified and eliminated, do not forget that it is imperative to replace the antifreeze, as well as flush the cooling system. It must be carried out according to a standard algorithm and using special or improvised means. In the event that a mutual exchange of fluids has occurred, and antifreeze has also entered the oil, then it is also necessary to change the oil with preliminary cleaning of the internal combustion engine oil system.

How to flush the cooling system from the emulsion

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

Before flushing, the 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 ones. In the latter case, it is best to use citric acid or whey. An aqueous solution based on these products is poured into the cooling system and ride for several tens of kilometers. Recipes for their use are given in the material “How to flush the cooling system”. After flushing, new antifreeze must be poured into the cooling system.

Hack and predictor Aviator

It is possible to use a car with oil in the cooling system only in the most extreme cases, for example, in order to get to a car service. Repair work should be carried out as early as possible with the identification of the cause and its elimination. Using a car that mixes engine oil and coolant in the long run is fraught with very complex and costly repairs. So if you notice oil in antifreeze, sound the alarm and get ready for the costs.