When using a vehicle, regardless of the type of internal combustion engine installed, owners quite often note a phenomenon where fresh engine oil quickly turns black after a change. A burnt smell may also appear in the oil, which can be clearly felt after 200-500 km. mileage In a similar situation, almost all drivers wonder whether the oil in the engine should turn black and how quickly this happens.

We also recommend reading the article on how to choose the right engine oil for the winter. From this article you will learn about the features of selecting winter engine oil, as well as the main requirements and instructions when choosing engine oil for winter.

At the very beginning, it must be emphasized that there can be several circumstances for blackening of the lubricant. In some cases, rapid darkening is the norm, while in others it may indicate certain problems with the engine or poor quality of the engine oil itself. In this article, we will look at the main reasons why oil quickly turns black, and we will also answer the question of why oil turns black in a gasoline engine or diesel engine.

Engine oil darkens

Let's start with the lubricant itself. It is well understood that any motor oil is a mineral, synthetic or semi-synthetic base, which also contains a package of active additives. The indicated additives allow you to comprehensively improve various operational properties of the lubricant: reduce friction losses, stabilize temperature characteristics, extend the service life of the oil and slow down its aging, provide a cleaning effect, etc.

In the list of chemical additives to the base, a separate space is occupied by the alkaline number of a particular motor oil. In other words, the lubricant must contain alkali. The main task of this additive is to neutralize acids that form in the internal combustion engine during operation of the unit and then enter the lubrication system. Alkaline additives also intensively combat the appearance of deposits in the engine, wash away carbon deposits, coke, etc. To put it simply, the alkali in motor oil protects against oxidation and improves cleaning properties, allowing you to keep the inside of the unit clean.

It turns out that the ability of the oil to wash away contaminants will directly depend on the alkaline number. If we take this feature into account, then the widespread statement that high-quality motor oil does not actually have to darken in the first 3-5 thousand kilometers after replacement is a profound misconception. Typically, drivers who dealt with similar products 15-20 years ago are accustomed to assessing the properties of oil only by the rate of darkening. The fact is that in those years there were fewer additives and high-quality oil differed noticeably from the most accessible analogues in terms of the rate of contamination.

To put it simply, blackening of the oil was one of the main characteristics for changing it. A cheap lubricant could begin to darken after 400-800 km, while the most expensive options remained unstained for 2-3 thousand km, then gradually darkened by 5 thousand km. and then they turned black. Note that the color of the lubricant changed not as a result of the additives, but taking into account the parameters of the base oil. Now the situation has completely changed, because modern motor oils contain a huge amount of active additives.

Darkening of the oil indicates that the lubricant is holding and binding chemical components, deposits, etc. It turns out that acids do not have contact with parts, corrosion slows down and engine wear is minimized. During the process of replacing the lubricant, contaminants are combined with the used oil and do not settle on the surfaces of the parts. In other words, everything turns out exactly the opposite - if the oil does not turn black for a long time, then it does not wash or clean the engine, and does not provide reliable protection against harmful products. The long-term transparency and purity of the oil indicates that the lubricant is simply not capable of performing cleaning functions.

It is also useful to know that if there are not enough alkaline additives in the lubricant, then if the service replacement interval is exceeded, the engine will be subject to intense contamination and accumulation of deposits. In a number of different cases, the indicated contamination leads to a decrease in the throughput of the lubrication system channels, as a result of which the pressure in the system decreases, the lubricant is supplied to the loaded friction pairs in an insufficient volume, oil starvation and increased wear of the unit occurs.

Along with this, the temperature regime is disrupted at the interface points, and an increase in the friction force leads to overheating. Also, clogging of the oil system channels does not allow the circulating lubricant to fully ensure heat removal. Ultimately, damage to internal combustion engine parts occurs, crankshaft connecting rods or main bearings rotate, rockers fail, hydraulic compensators become clogged, etc. Specifically, to effectively counteract and prevent possible consequences, manufacturers add alkaline additives in a balanced manner. Let us add that immediately after the freshest lubricant enters the engine, the active work of the additive begins, in other words, the aging of the lubricant occurs. With mileage, the additive gradually loses its characteristics, the degree of protection of the engine from acids and deposits worsens, which is the reason for the next oil change.

It turns out that the service life of a modern lubricant is determined not by color, but by how long the alkaline detergent additive will remain in working condition. This highlight is one of the main reasons why the lubricant must be changed taking into account strictly defined intervals (on average, 10-15 thousand km in the CIS, which depends on the properties of the fuel). It becomes clear that oil is intended not only for lubrication, but also for cleaning. For this reason, its darkening during operation can be considered completely common.

Note that the lubricant darkens especially quickly in engines that were initially contaminated. In other words, darkening means that the oil is intensively washing the engine. Given this fact, the purity of the oil should be more alarming, in other words, when its color does not actually change with mileage. This may indicate that the lubricant has low cleaning ability and the engine is not cleaned.

For better understanding, it is enough to remember the individual characteristics of the lubrication system. Engine oil is pumped from the engine crankcase using an oil pump, then circulates through separate channels. The lubricant protects parts from dry friction, while at the same time carbon deposits and deposits are washed away, which then enter the crankcase. It is also necessary to take into account the highest temperatures at which the oil operates. As a result, the color of the material uniformly changes to the most black and this happens in a short period of time.

Should I worry if the engine oil does not turn black?

Motor oil has a characteristic light yellowish color. And it is well known that it darkens over time.

But sometimes for some reason this does not happen, and then the question arises: is everything okay with the lubricant and the engine? Does anything need to be done in this case?

Composition of modern oils. Motor oil normally contains many special additives, that is, additives that perform various functions. They improve the lubrication of metal parts, prevent their corrosion, and also help remove carbon deposits from the internal surfaces of the engine. Each motorist can choose and combine additives at his own discretion.

Why does the oil darken? The fact is that parts of an internal combustion engine during operation are covered with dark brown resinous deposits. And they must be removed regularly. When this does not happen, the engine overheats and the oil passages become clogged. As a result, the motor works worse, is unstable and may prematurely become unusable altogether. One of the main tasks of additives in motor oil is precisely to dissolve the described deposits. Naturally, they accumulate in liquid. As well as tiny metal shavings that separate from parts due to intense friction. Plus, soot and fumes are mixed into the oil. And all the time until it is changed, a portion of oil moves in the system in a vicious circle. So its color becomes darker and darker.

But it is important to emphasize that the speed and intensity of darkening of engine oil is not always the same. This is most influenced by two factors: -The degree of contamination of the parts inside the engine, that is, the accumulation of substances in it that can “color” the oil in a dark color.; -The quality and proportions of alkaline additives present in the motor oil used.

It is known that in new engines the oil becomes contaminated more slowly - after all, it is quite natural that brand new parts have not yet had time to “accumulate” a large number of deposits. And engines with a long service life, namely work, and not life in general, are characterized by greater clogging of the “filling” and, accordingly, are more likely and more intensely capable of contaminating the lubricant circulating through them.

How does the light color of the oil correlate with its low quality. Summarizing the above, we can come to the logical conclusion that when, after a long run, the car’s oil still retains a light color, this indicates one of two problems: - there are no cleaning additives in it at all; - there are cleaning additives, but they do not work effectively. In any case, the previously described waste does not leave the engine, but settles on its surfaces, forming carbon deposits.

Bottom line. A car owner should definitely be concerned that in a car that is used frequently and heavily, the oil still retains a light color. In this case, there can only be one action - the unusable oil must be drained as soon as possible and replaced with fresh and high-quality one. You should give preference only to trusted manufacturers of automobile oils and purchase them only in specialized stores.

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The engine oil quickly turned black

As already mentioned, darkening of the oil indicates that it is working, in other words, it intensively cleanses the engine of contaminants. In this case, it also happens that the oil does not simply darken, but becomes black and more similar to fuel oil. In this case, it is worth paying special attention to this point and finding out why the engine oil quickly turns black.

• At the very beginning, you need to remove the oil dipstick and wipe off the oil with a clean rag. Remains of dark stains will indicate that the lubricant in the engine is burning out. The prerequisite may be significant wear of the CPG, in other words, oil enters the combustion chamber. At the same time, the fuel also flows into the motor boat, diluting the lubricant. As a result, the working fluid of the internal combustion engine lubrication system loses its protective, cleaning and other useful characteristics. It turns out that rapid blackening of the oil indicates the presence of problems with the engine itself. Additional symptoms are usually increased fuel and oil consumption, decreased engine power, smoky exhaust, difficulty starting when cold, etc.
• The second prerequisite that explains why the oil in a diesel engine quickly turns black or the lubricant in a gasoline unit turns black is overheating of the oil. A rapid change in color to dark occurs if the engine is constantly operated in languid modes at high speeds and the greatest burden. Also, the oil overheats when the lubricant was initially selected incorrectly according to its viscosity characteristics. Practically, boiling occurs, the lubricant becomes a homogeneous dark-colored mass.

It becomes clear that in case of problems with the CPG, the engine needs repair. If the oil is not suitable for this type of engine, then such lubricant must be immediately changed to a suitable option, which is recommended by the engine manufacturer and meets all tolerances. You should also not forget that the engine may have been filled with a low-grade fake. For this reason, it is recommended to obtain fuel and lubricants only at proven sales points.

Remember, the upcoming operation of the engine with black oil can lead to severe damage to the unit in the absence of existing problems, as well as additional dilemmas when postponing repairs and changing the lubricant on units in which blackening of the oil is seen due to wear of individual parts.

Why does engine oil quickly turn black?

On any auto forum there are topics where people argue and prove that if the oil in the engine quickly turns black, then this is bad and that the engine will soon go to capital, because It's already worn out so much that it's time.

Others argue that a little dark is normal and how it should be. Where is the truth?

But there is no truth as such. If you take any specific car, it may work well, but the exact same one may require capital. And all because different owners use their cars differently!

Therefore, black is not enough, especially with a diesel engine, it does not always mean that the engine is time to be repaired or replaced.

There is a possibility that the engine is in a damaged condition if you buy the car second-hand, and the seller may not be the first owner. Therefore, no one can tell how the car was used before you:

1. whether all manufacturer's recommendations were followed;
2. the oil and oil filter were changed in a timely manner;
3. the oil complied with the tolerances;
4. Is the fuel poured in good quality?
5. in what conditions the car was operated (taxi, transportation, extreme sports).

That is why it is impossible to answer unequivocally that dark oil is bad. On the contrary, this is good, because detergent-dispersant additives work, i.e. the oil absorbs the products of incomplete combustion (soot, soot, carbon deposits, varnish deposits), leaving the engine clean, provided that the engine is in good condition.

How quickly should engine oil darken or turn black?

So, all oils, regardless of types and brands, sooner or later darken. With all this, one product may turn black earlier or later than another. Note that the rate of darkening is influenced by a number of general and personal reasons, among which experts identify:

It goes without saying that if the lubrication system already has various deposits in the channels, then accelerated blackening can be considered normal. Moreover, the more detergent additives in a certain type of lubricant, the faster the lubricant will darken. It should also be taken into account that after adding fresh lubricant, it begins to intensively wash away old deposits, which later accumulate not only in the oil itself, but also in the oil filter. This means that during the first service interval, when the lubricant is quickly darkening, it is better to change the filter twice or more. The replacement interval itself can also be reduced by 20-40%.

This approach will allow you to “gently” remove deposits that circulate through the oil system. In other words, the engine is evenly washed by the engine oil itself, which changes in advance, in other words, before the loss of cleaning parameters begins. Let us add that for high-quality cleaning it may be useful to change filters and oil according to this scheme not just once, but several times.

Another cleaning method is the introduction of flushes into the oil, as well as short-term operation of the internal combustion engine on the so-called flushing oils. Note that these methods have both advantages and disadvantages. In short, flushes have a negative effect on rubber seals and can also lead to various unpredictable chemical reactions after mixing with the base lubricant.

An additional aspect is that after the deposits in the engine are softened by flushing, they can clog the channels of the lubrication system. In such cases, the risk of early failure of the working unit increases. If the oil quickly turns black due to gases entering the crankcase, then the engine needs decarbonization, replacement of the piston rings, or serious engine repairs.

We also recommend reading the article about how to wash the engine before changing the oil. From this article you will learn about different methods of flushing the lubrication system before changing the lubricant.

Taking into account the above, we can come to the conclusion that if the oil turns black, but lubricant consumption remains normal, then you can start by cleaning the oil system. After removing the contaminants, the rate of blackening should return to normal or significantly slow down. If there are problems with the mechanical part, then the problem will go away only after the unit is repaired.

Engine oil turns black quickly: is this good or bad?

1. If the engine is dead and the oil is black, then this is bad. Qualified specialists in a car service center should understand the reasons for poor engine performance, and not guess on the tea leaves, throwing out options;
2. If the engine is in good condition, but coked, then the oil in the engine quickly turns black because it washes away the remaining dirt that the previous oil could not cope with (low-quality oil, rare replacement);
3. If the oil is light, then perhaps the engine is in perfect technical condition and therefore there is nothing to wash (all components and assemblies work perfectly);
4. If the oil is light, then you may have come across counterfeit motor oil or simply a cheap motor oil that has very cheap or low-quality detergent-dispersant additives that cannot cope with the products of incomplete combustion, i.e. don't absorb them. Consequently, the oil is light, and the engine becomes coked.

But all this is general, and why the engine oil quickly turns black or remains light from replacement to replacement, you need to understand the specific engine, taking into account that the ignition of a gasoline and diesel engine is different, which means the rate of darkening of the oil will be different.

What's the result?

As you can see, rapid darkening of oil cannot now be considered a sign of its disgusting properties. If the motor is working properly, then the rate at which the lubricant color changes to black or dark will depend on the degree of contamination of the motor and the alkaline number of the oil used.

Under similar conditions, oils with the least amount of alkaline additives will darken more slowly and clean the engine more poorly than their highly alkaline counterparts. With all this, a lubricant with the highest cleaning properties can darken after 300-400 km traveled. Along with this, darkening of the oil does not mean that it is time to change it. Active additives and alkalis are washed off and then retain the dirt in the oil, allowing the lubricant to work throughout its entire declared service life.

We also add that when choosing a lubricant, you should take into account a number of additional features, and not just its cleaning characteristics. The fact is that oils with a huge alkaline number have a short service life (on average, about 6-7 thousand km). The fact is that such products usually do not contain a huge amount of additives that slow down the aging process of the lubricant. In other words, oil with good cleaning ability is designed for the shortest service life and is subject to accelerated oxidation and aging, which means the need to reduce the interval and replace it more frequently.

Source: krutimotor.ru
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What to do if the engine oil darkens

The answer to the question “what to do?” depends on the cause of the darkening. We list general recommendations based on the reasons mentioned above and methods for preventing this phenomenon. That is, what actions to take so that the darkening is natural and not a “pathology”.

First . Buy original high-quality motor oil. The choice of oil depends on a large number of factors. Try to shop in trusted stores. There is currently a growing trend of popular lubricant manufacturers protecting their products online. That is, the authenticity of a canister of oil can be verified using a smartphone connected to the Internet.

Second . Regularly monitor the condition of your car's engine. Monitor the functioning of the elements of the cylinder-piston group, oil scraper rings, gaskets, seals, in a word, prevent mixing of fuel and oil in it.

Third . Change engine oil regularly. Ideally, this should be done in accordance with the car manufacturer's recommendations. Usually the corresponding value is indicated as 10...15 thousand kilometers. However, in this case it is better to judge by engine hours . After approximately 250...300 hours of engine operation, the additive responsible for containing dark deposits stops working, and deposits begin to settle inside. If, when checking the condition of the lubricating fluid, it was discovered that it contains carbon deposits and/or solid particles, then it is better to replace it as quickly as possible. In some cases, it makes sense to flush the engine with special compounds. As practice shows, when driving slowly in a metropolis (especially with numerous traffic jams), it makes sense to change the oil already after 7...9 thousand kilometers.

Fourth . Constantly check the oil level in the engine crankcase using a dipstick, and do not allow its value to fall below the MIN mark (but too much oil is also harmful). Similarly, if the warning light on the dashboard indicates a decrease in oil pressure, you must immediately check its level and, if necessary, add lubricant.

Fifth . Use the oil prescribed by the car manufacturer. This applies to both viscosity values ​​and other operational characteristics, in particular, car manufacturer tolerances, API standards, ACEA, and so on.