darkening oil, then something is wrong, some car owners think. But is it really so? After all, it is one thing when it quickly turned black after replacement (still almost fresh), and another if after a couple of thousand kilometers.
There are several reasons why this happened - poor-quality lubricated fluid, dirty engine condition, long mileage of the car without replacement, switching to better oil, overheating, even due to poor fuel. How to understand when engine oil quickly darkens is good, and when is it bad? After all, this is not always a negative consequence and you need to worry. Then be sure to pay attention to additional factors and.
gradual aging and darkening is a natural process. Therefore, the main task of the motorist is to figure out whether the darkening is caused by positive or negative factors.
Dark oil is normal
So why does the oil in a car engine darken? Is it normal or not? The blackening process is due to the fact that, among other functions of the lubricating fluid, there is also a cleaning fluid. During the operation of the engine, fuel is burned with the appearance of complex chemical compounds, the composition of which largely depends on the type and quality of the fuel, but they are always harmful to the engine. These residues are located directly in the engine (on the cylinder walls, pistons, rings, and so on).
One of the tasks of the oil is to clean these deposits from the surface of the listed parts and maintain them in its composition, preventing them from being deposited in the engine. That is, the remains of fuel combustion pass into the composition of engine oil, and this leads to its natural darkening.
Dark oil in the automatic transmission appears for similar reasons - due to the cleaning of the box parts, in particular, due to the wear of the clutches. Moreover, ATF has high washing ability, and therefore quickly darkens. Plus, the degree of darkening depends on the mileage and the previously used lubricant.
Pay attention to the difference in fuel used and the degree of darkening of the engine oil in the engine. When diesel fuel is burned, darker exhaust gases are formed, and blacker deposits in the engine are similarly formed. This means that the oil darkens faster. As for engines running on gas (methane, propane, butane), the situation is reversed. Due to the chemical composition of the gas, there is less mud deposits (as in petroleum products), so they produce much cleaner exhaust gases. Accordingly, the engine oil in this case will be cleaner. And then, on the contrary, those who know that it should change its color will be interested in why the oil does not darken. With traditional use of gasoline, the condition of the engine oil will be somewhere in the middle between diesel and gas.
Oils designed for engine operation on gas do not darken so quickly, and there is a situation where the oil will not be very dark until it is changed.
Another important question in this context is after how many kilometers should the oil darken. If the oil darkens quickly (almost immediately after changing it or with a short run), this is an occasion to perform diagnostics and search for the causes, which will be discussed later. If the oil darkens naturally, approximately two to three thousand kilometers- this is most likely a natural darkening process, and if there are no additional symptoms of an engine malfunction (it works stably, not), then there is no reason to worry.
Reasons why the oil darkens
Using better quality oil
When there is a better quality oil in the crankcase than was used before, it will begin to darken faster, because it really began to clean, and not just lubricate. It is known that different manufacturers can differ in compositions not only, but also in the number of detergent additives (not to mention different types). Therefore, if a replacement was made, then there will be more washed out deposits in high-quality oil (which means it will be darker), than what it was before.
You can ride on such oil, but you need to carefully monitor its condition with a dipstick. If it looks uniformly viscous and uniformly dirty, then the cleaning process is going well. However, it makes sense to replace the lubricant a little earlier than it should be according to the regulations.
natural darkening
That is, the use of really high-quality oil. As described above, if the oil does not darken abruptly, but changes its color gradually, then everything is in order, and it simply does its job of cleaning the engine elements from carbon deposits and oxidation products, and at the same time keeps them in suspension (in a moving volume ).
Timely oil change provides reliable protection of engine elements from friction, overheating, excessive wear. And in the long run, it prevents the “oil burner”.
More or less high-quality oil becomes almost black (but not thick) by about 2 ... 3 thousand kilometers. If the oil is not of very high quality, then it will turn black somewhere around 800 ... 1000 kilometers, or vice versa, even after 3 thousand km it will remain light (when it does not have cleaning properties). This is true for gasoline engines. As for diesel engines, their oil turns black approximately twice as fast, that is, on some engines it can be dark even after a thousand kilometers.
Another interesting fact is that the engine oil will darken faster if the power unit has recently been overhauled. In this case, the darkening is caused by a large amount of metal chips formed as a result of the interaction of rubbing pairs. After the "capital", it is recommended to change the oil earlier than the deadline set by the regulations.
High ash content and low TBN
Engine oil is an indicator for determining additives that contain organic metal compounds (in particular, their constituent salts of zinc, potassium, magnesium, calcium, barium, sodium and other elements). In simple words, this indicator characterizes the number of fireproof elements during waste and the washing ability of the oil. Sulphated ash content in this context is interesting in that it is directly proportional to the base number (TBN).
Often in the performance characteristics of oils (on canisters or in the description in the store) you can find information about the value of sulfate ash content and / or base number. And so the higher they are- the higher the washing ability of the lubricating fluid, and hence the darker the oil will be during operation. And vice versa, the lower these values are, the more transparent it will be.
Therefore, the reason for the darkening of the oil can be a high ash content. But these values are selected and recommended by the automaker for a particular motor. Please note that oils with a low base number require more frequent replacement, approximately every 6-7 thousand kilometers. They are very sensitive to fuel quality and lose their properties faster.
Now let's move on to negative reasons, that is, those from which it is worth getting rid of.
Fake
The crankcase is filled with fake oil. Unfortunately, at present this problem is very relevant, because almost all popular brands of oils are clandestinely produced fakes. Naturally, their products are of very poor quality, do not fulfill the functions assigned to them, and, among other things, quickly darken. Such oil must be replaced with the original as soon as possible. Preferably flush the engine.
This also includes the case when the car owner buys low-quality oil of some little-known brand at a low or average price. Such compositions often have low performance characteristics, and as a result, they quickly lose them, which is expressed, among other things, in their rapid darkening.
Ingress of combustion products into the oil
In this case, the oil begins to quickly oxidize, loses its performance properties, and, among other things, changes its color to a darker one. The main reason here is depressurization, and it, in turn, can be caused by various reasons - breaking through the cylinder head gasket, damage to the oil scraper rings, and so on. Gasoline can also get into the oil, it dilutes it and changes its color. If there is a weakening of the oil scraper rings of the piston, then a situation arises when the oil, remaining on the walls of the cylinders, burns out along with the fuel. In this case, the oil will also turn black. As a rule, in this case, excessive consumption of lubricating fluid is observed.
In any case, you need to audit the engine yourself or seek help from a car service. If there is a malfunction of the engine, then within the framework of this article it is impossible to unequivocally answer the question of why the oil in the engine darkens.
Crankcase gases getting back into the engine
If the crankcase ventilation system is faulty, the latter can enter the engine again and come into contact with the lubricating fluid. Because of this, it oxidizes faster, loses its performance properties and darkens. And the more gases enter the engine, the faster the mentioned process occurs.
Poor quality fuel
Since the main cause of darkening of the oil is the combustion products of gasoline / diesel fuel, the composition of the fuel in this case is very important. The cleaner the fuel (made to a higher standard, does not have additional impurities), the darker the products of its combustion will be, and hence the darker the engine oil will be. Therefore, try to fill the tank with good fuel, this will not only increase engine power, but also protect it from excessive wear, and also increase engine oil life.
There is an opinion that in the CIS countries only diesel fuel has a lot of impurities, but in fact this is not so. Gasoline is also generally of poor quality. You can verify this by simply igniting it and looking at the color of the outgoing smoke.
Oil overheating
If the engine has been running for a long time or continuously under severe conditions (high ambient temperature, poor ventilation, high rpm/load), the engine temperature will naturally become very high. And as a result, the oil used too. Under such conditions, the lubricating fluid will literally “roast” and blacken. And this is all the more relevant, the older the oil is, firstly (a large mileage was made on it), and secondly, its level in the crankcase is lower.
In the worst cases, the lubricant can turn into a kind of fuel oil under difficult conditions, and this can lead to very sad consequences, up to an engine overhaul. Therefore, you should try not to operate the engine constantly under critical loads, or choose oils with appropriate performance characteristics (viscosity, tolerances, and so on). By the way, the wrong choice (very thick or, on the contrary, very liquid) can also often lead to overheating of the engine as a whole and the oil in particular.
Outcome
If the oil darkens gradually, and at the same time the engine is running normally, there is no reason to worry. Under normal conditions, the oil darkens after about two thousand kilometers. Then it starts to blacken and thicken. If the lubricating fluid acquired a dark shade very quickly (after a run of 300 ... 500, maybe up to a thousand kilometers for a gasoline engine, in some cases it can even immediately after replacement), then this is an occasion to think and perform engine diagnostics. If your car runs on gas, then the oil is usually transparent even with a significant mileage (however, you still need to change it according to the regulations, despite the transparency).
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 “pathology”.
First. Buy original high-quality motor oil. associated with a large number of factors. Try to shop at trusted stores. There is currently a growing trend for popular lubricant manufacturers to protect their products online. That is, the authenticity of the oil canister can be checked using a smartphone connected to the Internet.
Second. Regularly monitor the condition of your vehicle's engine. Control 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. Regularly. Ideally, this should be done in accordance with the recommendations of the automaker. Usually, the corresponding value is indicated at 10 ... 15 thousand kilometers. However in this case it is better to judge by engine hours. Approximately after 250 ... 300 hours of engine operation, the additive responsible for the content of dark deposits in itself stops working, and deposits begin to settle inside. If, when checking the condition of the lubricant, it was found that it contains carbon deposits and / or solid particles, then it is better to replace it as soon 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 at 7 ... 9 thousand kilometers.
Fourth. Constantly check the oil level in the engine crankcase with a dipstick, do not allow its value to fall below the MIN mark (but also harmful). Similarly, when the oil pressure warning light on the dashboard is activated, check its level without delay and top up the lubricant if necessary.
Fifth. Use the oil recommended by the car manufacturer. This applies to both viscosity values and other performance characteristics, in particular, automaker tolerances, API standards, ACEA, and so on.
sixth. When switching to a higher quality oil (with a large amount, including detergent additives), it makes sense to use an engine flush. However, this is not recommended if engine has high mileage and it constantly used not very high-quality oil. In this case, there is a risk that the detergent additives of the new lubricating fluid will remove coking from various places where friction parts are produced and / or microcracks in the oil system, and this will lead to its depressurization, oil leakage and compression loss.
High mileage engine can kill not only washing, but also use of oil with a large amount of detergent additives, especially if poor-quality lubricating fluid was previously filled in.
seventh. Change the oil filter in time. Its mandatory replacement is carried out when changing the oil. However, on many machines, regulations require that the corresponding filter be changed much more often. Read this information in the manual of your machine and follow the recommendations given there.
eighth. Try to fill the tank with good fuel, that is, refuel at proven gas stations, and vice versa, do not fill the car with any surrogate, which can often be found on sale at low prices.
ninth. Do not operate the engine at excessive loads and/or high speeds. If you need to use the machine at a high ambient temperature, you must ensure the normal operation of the engine ventilation system, as well as select an oil with the appropriate characteristics (viscosity and temperature tolerances).
tenth. Constantly monitor the good condition of the crankcase ventilation system. Do not allow them to get back into the engine. If you suspect a corresponding malfunction, you must immediately carry out an audit and, if necessary, repair.
It is not difficult to answer the burning question of car owners about why the oil in the engine quickly turns black. The lubricating mass gains and retains the exhaustion of burnt fuel and metal oxides of rubbing surfaces. However, many have difficulty imagining the process in which engine oil is involved. Seeing that it is getting dark, motorists perceive this as a bad sign and try to find out the reasons. The main concern is the use of low-quality lubricant.
Why does a car need lubrication?
To get rid of a false alarm, you need to figure out how the oil works in the engine. In gasoline and diesel power units, lubricant is a universal product. It not only serves the sliding of surfaces, but also cleans them from the inevitable technical dirt. For this purpose, the lubricant contains various additives that are responsible for correcting the base number inherent in the product.
If the engine oil is dark, this means that the alkali is doing the necessary work. The substance neutralizes acids, eliminates deposits of dirt and soot. Naturally, the lubricant quickly darkens in the process of continuous cleaning of engine components. The invariance of the original color of the lubricating and cleansing mass, on the contrary, indicates its insufficient effectiveness. That is why, after seeing a clean lubricant after a long operation, the motorist should be alert. It is likely that there is a fake that does not perform the main functions. It is precisely because low-quality counterfeit is useless and does not absorb dirt, respectively, the lubricant does not darken.
Often the causes of mud deposits in vehicle components and, accordingly, their accelerated wear lie in the low content of alkaline additives. Conversely, a quickly darkened oil in a gasoline or diesel engine indicates the sufficiency of the base number and its cleaning ability. Proper lubrication will help to avoid two main causes of malfunction of the unit:
- Oil "starvation" due to the appearance of contamination zones that complicate the penetration of the oily liquid.
- Violations of the temperature regime of the engine, as mud deposits prevent heat removal. Local overheating as a result will lead to the destruction of the camshaft, rotation of the liners, and other malfunctions.
However, it should be recognized that problems can also arise with a high alkali content - if the engine oil is not updated on time. The additive quickly becomes obsolete, struggling with abundant contamination, which, in turn, reduces the quality of cleaning.
Turns black - it means it works
The automotive oil system is a closed circuit. From the crankcase, the oil pump drives the lubricating fluid through the channels of the system. Making a full turn, the engine oil picks up soot, oxides and returns to the crankcase. That is, the product permanently circulates through the dirtiest "back streets" of the internal combustion engine (internal combustion engine). It is quite natural that over time the grease turns black.
In this case, one should not forget about the temperature regime in which the oil is located. Its temperature often reaches over 100°C. High heating contributes to the effective lubrication of the nodes and the thorough removal of carbon deposits - this is another reason for darkening. This color change is called "oil work". From this we can conclude that if the oil does not darken after a long run, it is deficient in cleaning additives. Naturally, all oxides, deposits and other slags remain inside the engine, settling on its nodes. In this case, you just have to exclude a low-quality product from your purchases.
Causes of blackening
Is the oil dark or black? Such conditions can cause various causes, which are not necessarily hidden in the low quality of the lubricant or excessive contamination of the automobile engine. Engine oil, which not only turned dark, but became a black liquid resembling fuel oil, indicates its combustion in the engine cylinders. To find out, wipe the dipstick with a clean rag. Black marks left on the fabric in the form of soot will confirm the burnout of the grease.
This problem is caused by the wear of the piston group. Part of the unburned fuel penetrates the gap between the cylinder and piston, mixing with the lubricant. In addition, the weakness of the oil scraper rings of the piston allows some of the oil that burns out with the fuel to remain on the cylinder walls. In this case, the presence of black oil warns the car owner of a problem that can lead to increased fuel consumption and loss of engine power.
An equally common reason for the black color of the lubricant is its overheating inside the engine. Due to the wrong choice of oil viscosity characteristics and during prolonged operation of the engine at high speeds, the lubricant boils. The additives break down, turning the once-clear liquid into black oil. In this case, it is better to quickly change the lubricant. After all, it has already lost its consumer properties and can only harm the oil pump, filter and other components.
How to solve a problem
How to prevent darkening of the oil or get rid of the consequences of this problem? Here are a few main factors why auto lubrication darkens very quickly:
With improper care, the contamination of the automobile engine increases up to the clogging of the oil channels. This state is unsafe for the operation of internal combustion engine components and cylinders. Therefore, immediate flushing and replacement of the oil filter is recommended. It is even better to change the filters several times during the prescribed run cycle, which contributes to cleaning. Standard cleaning should preferably be carried out without the use of aggressive flushing agents.
Chemically hard components partially remain inside the oil system - this is why the oil turns black. In addition, flush oils have a much lower viscosity level, which cannot be considered beneficial when mixed with a newly filled "native" lubricant. As a result, the engine is threatened with increased wear. It is better to shorten the run cycles between service oil changes.
The oil turns black due to a breakthrough into the crankcase of exhaust gases. This dramatically increases the consumption of fuel and lubricants. Such a problem may require major repairs. The problem is partially solved by boring the cylinders and replacing the piston rings. However, such troubles are found, as a rule, in older cars with impressive engine wear.
During a service run of the engine, engine oil, blackening due to the abundance of alkaline additives, is recommended to be changed several times along with filters. After gradual cleaning of the unit, the color of the lubricant returns to normal. However, it should be remembered that the operation of the car in normal mode involves the change of high-alkaline oil every 5-7 thousand km.
If the engine oil quickly becomes dark, do not be afraid. This means that it is doing its job - it cleans the engine of deposits. Change the lubricant in a timely manner and buy only the original product.
Recall that on a serviceable car, the oil suddenly turned into a thick black slurry, after which the motors were sent for a “capital” or replacement - untimely and extremely expensive. without even asking our permission. Well, that's okay...
Summary previous article - a wave of sudden engine failures has swept through branded car services (and not only), associated with incomprehensible and unpredictable behavior of engine oil. Without any warning, the oil suddenly turned into a black oil, began to burn out very quickly. The result - overhaul or death of motors.
The epidemic hit cars regardless of their brands and manufacturers. Cases of the disease were registered in Moscow, and in St. Petersburg, and in Magnitogorsk, and in Murmansk - that is, almost throughout the country. And it was also noticed that the “sick” were mainly cars serviced at serious car services, in which barrel branded oil was poured. The situation was aggravated by the fact that these cases were irregular, met infrequently, but with enviable regularity. And, as any diagnostician knows, it is the “floating” defect that is the most difficult to catch.
The cause of this illness was incomprehensible, there were only hypotheses, but you can’t build a lawsuit in court on them (and most often it was the case that reached the court in proceedings). And then we promised to try to deal with the situation and acquaint our readers with the results.
Six months of work of our testing laboratory was not in vain. We managed to simulate a number of situations in the laboratory and, finally, get clear manifestations of this “deadly disease”. The symptoms that we will catch are a sharp increase in viscosity, a drop in alkaline and an increase in acid number, the deposition of thick tar-like deposits on the engine walls that prevent oil from pumping through the channels of the lubrication system.
IS THE OIL IN THE CANISTER SEPARATED? IS THERE RESIDUE? TO THE WASTE!
FALSE TRAIL
Let's start with the typical "excuses" of dealer service stations, on the basis of which they are trying to fight off warranty repairs. The inquisitive mind of warranty specialists usually wanders in three directions - the use of low-quality fuel; antifreeze or water getting into the oil; lack of control over the oil level in the engine during operation.
Let's immediately remove the third option - it is obvious that even with a very small amount of oil in the sump, it should not change its properties in the way that we see in cases of advanced "disease". When using a “healthy” oil, the engine will react to its small amount by lighting up the control lamps on the dashboard and sound alarms. First - with rolls and sharp accelerations and decelerations, when the receiving fungus is exposed. Any normal driver will respond to this immediately. And after topping up the oil, you will not feel any negative consequences in the future.
The most common alleged "reason" on the basis of which they try to void the warranty is the use of substandard fuel. Substandard in the understanding of service station mechanics is either a low octane number, or a high sulfur content in the fuel, or the presence of a large amount of tar in it. Let's say right away that, apart from sulfur, everything else, according to the current Technical Regulations, which regulates the quality of fuel, is not subject to control, therefore, it is not subject to jurisdiction. But, since there are such attempts at excuses, we will check.
FUEL - JUSTIFY!
Several bench engines, initially completely serviceable, were doomed to the slaughter. It’s a pity for them, but these are just pieces of iron, and living people suffer from the problem. Therefore - let these motors serve for the benefit of people.
Especially for the experiment, not without difficulty, they got 100 liters of fuel, more like a bodyagi. Instead of the declared 92 octane number, only 89.5 were measured, the sulfur content went off scale over 800 ppm, the tar was more than 3.5 mg / dm3. The manufacturer is unknown, but in terms of quality it is something from some kind of "samovar" - an amateur mini-refinery that distills gas condensate into supposedly fuel. Worse than ever! You have to dislike your car very much to feed it with such good things.
We fed the engine all the bodyag we got. And, in order to completely aggravate the situation and provide the oil with the maximum possible contact with disgusting fuel, they broke off the side electrode on one of the candles. Now the fuel entering the idle cylinder will fly into the crankcase in large quantities.
The motor self-diagnostic system was indignant, the check-engin burned brightly and incessantly all the time of torture. The motor shook and vibrated, but... survived! His autopsy revealed no problems - everything was clean and no black deposits were observed anywhere. The oil pressure, of course, dropped a little - the dilution of the oil by the fuel affected. At the same time, as soon as the damaged candle was replaced with a normal one, literally half an hour later, the arrow of the oil pressure indicator returned to its previous position. It is understandable, gasoline is a volatile liquid, and at operating temperatures the oil into which it has entered will not live there for a long time.
Measurements of the physico-chemical parameters of the oil did not reveal anything unexpected! The viscosity of the oil dropped a little - after all, some fuel fractions of the so-called gasoline remained in it. The alkaline number slightly decreased - from 7.8 to 7.4 mg KOH/g. The acid number increased by 0.3 mg KOH/g. The flash point dropped noticeably - from 224°C to 203°C. This clearly indicates that there was gasoline in the oil! But he couldn't kill him...
Moreover, in a real situation, its diagnostic system will be indignant at the poor-quality feeding of the motor in the first place. And this indignation is sure to leave an indelible mark on the computer logs. But in almost all cases when the warranty services refused to repair, motivating their decision to use low-quality fuel, the diagnostic system did not confirm anything of the kind.
Verdict: Gasoline not guilty!
SUSPECTED WATER
Water always gets into the oil in some quantities! It condenses from the moist air entering the cylinders and, together with crankcase gases, mixes with the oil. Coolant can only get into the oil if there is a leak in the cooling system - and only when the engine is stopped. During its operation, the oil pressure is higher than the pressure in the cooling system, and therefore the path for antifreeze to the oil is closed.
Well, let's try to simulate this situation. 3 liters of fresh oil were poured into the long-suffering engine, and then a whole liter of water was thrown into it! And what? Never mind! Of course, an emulsion formed in the sump, the oil pressure dropped noticeably. But the motor worked, nothing critical was heard or seen. And then - gradually the oil pressure began to grow and soon returned to the initial level. What happened? The water simply evaporated, the oil returned to its original state. The autopsy of the motor showed no problems - everything was clean again. Changes in the physical and chemical parameters of the oil after the ingress and subsequent evaporation of water turned out to be within the measurement error! And this is the reason for the withdrawal from the guarantee - to refuse for insolvency!
After that, they dealt with a similar situation by replacing the water with antifreeze. The result is the same, the engine survived. But the viscosity of the oil has grown - it is understandable, the water has evaporated, and the ethylene glycol remains in the oil. The alkaline number decreased slightly, the acid number increased. Yes, of course, if you drive an engine with a broken cylinder head gasket for a very long time, constantly adding antifreeze to the tank and not trying to deal with the situation, then in the end, you can probably achieve the death of the oil, and with it the death of the engine! But this is just an extreme case of a disregard for the engine. Yes, and here there will already be a situation - not “ethylene glycol in oil”, but “oil in ethylene glycol”.
Conclusion - such a reason can only be considered when it was preceded by a long and constant loss of coolant in the engine. And with a complete lack of control of the condition of the oil at the same time. This is also not our case.
Verdict: It's not the coolant's fault!
GOT!!!
We checked two more versions. And, looking ahead, let's say - THEY WORKED!
The first one was suggested by oil specialists, with whom we constantly communicate. In their opinion, the picture that we are seeing, that is, a sharp increase in oil viscosity, may be associated with unexpected polymerization of some components of the additive package. The reason for this disgrace is the volumetric overheating of engine oil. And they remembered that at their seminars, some manufacturers of oils and cars, since recently, began to give a clear recommendation - if suddenly the oil was overheated, then you urgently need to run to the nearest service center and change it!
We tried to overheat the oil on a bench motor. It was not difficult for us to do this - we had to turn off the external engine airflow and select the appropriate operating mode. Unlike most cars, our sump oil temperature is constantly displayed on the control panel. Indeed, it rose by 20...25 degrees. This torture continued for many hours. Two oils worked fine, withstanding such a mockery. But the third behaved strangely - it began to noticeably thicken. And then, in the drain tank, where they left its remains for a couple of days, traces of oil separation were found. It drew the same “tar” that we observed on the walls of motors killed by oil. Both on the inner surface of the cylinder block and on the side surfaces of the pistons, there was much more contamination than usual.
So, we opened one option for the death of oil. But they didn’t experience much joy from this - after all, it’s not clear how you can track the real temperature of the oil in the sump in a living car? Indeed, in new cars, even the coolant temperature gauge was removed! It turns out that this information is not even redundant at all!
Let's go further... We remembered how it all started. It all started with a letter from our reader, who, having bought a canister of oil from a very well-known company for topping up, suddenly discovered in it ... an incomprehensible sediment! And from the answer of a technical specialist of the Russian representative office of this company, who, to our request for an explanation of the situation, literally uttered the following: “I hereby inform you that a small amount of sediment is allowed in motor and transmission oils. It can be caused by the association of fine catalyst particles that are smaller than the pores of the factory filter element. These sediments... can be up to black in color. They are rare and, as a rule, only in those batches of oil that were made immediately after reloading the fresh catalyst in the apparatus. They do not affect the performance characteristics of commercial oil and, subsequently, in the process of operation, they again turn into a finely dispersed state.
At one time, our oilers were shocked by this answer! That is, one of the world's main oil producers honestly admits the possibility of a gross violation of oil production technology!
And we compared what is written and what we saw with our own eyes. After all, the premature death of oil is very similar to the picture that we could see due to a sharp acceleration in the rate of oil oxidation. It is this process that is accompanied by an increase in its viscosity and acid number, a drop in base number. And what can contribute to the uncontrolled acceleration of the chemical reaction, which, in fact, is the oxidation of oil? Precisely the presence of a catalyst!
Yes, of course, when storing such a “dirty” oil, the catalyst will be silent - after all, to activate its work, it requires special conditions, temperature and pressure. But they are just in the active zone of the friction units. So, check this out too!
The main problem that has arisen before us is where to get this catalyst? Only the Russian representative office of MOTUL responded to our requests for help in this matter. It seems that only they, by the way, never exposed in cases of premature loss of oil, found it necessary to establish the truth! For this we sincerely thank them, and let them not consider our thanks as an advertisement for this company.
So, we have two options for the catalyst used in the production of hydrocracked base oil. We turned large granules of catalysts into a fine-grained powder of the desired fractional composition - such that it would fly through the pores of the oil filter. These powders were mixed with oil, and after half an hour they saw - here it is, a harmful sediment!
This oil was poured into the next engine, intended for slaughter, and a cycle of its long knurling began. At first everything went well, but after twenty hours of testing they began to notice that the oil pressure was dropping. And the oil on the dipstick became noticeably thicker - all the more, they initially used very good “synthetics” 5W-30, against its background, the increase in viscosity was especially noticeable! It's strange - the viscosity is clearly growing, and the pressure is dropping ... Maybe wear has appeared? But somehow this process progressed too quickly. The motor withstood only 40 hours of testing, after which the pressure completely disappeared. Then - everything, as usual, an autopsy, measurement, inspection.
The first thing that caught my eye was that from four liters of oil initially poured into the engine, only one and a half liters merged from it as a result of tests! And this is - in just 40 hours of very moderate modes, in terms of equivalent - less than 3000 kilometers! And the oil was terribly black. Measurements of engine parts did not reveal serious wear, although it was noticeable - the bearing shells and crankshaft journals were somehow very well polished. It is also clear - the catalyst powder worked as an abrasive. So why did the oil pressure drop so much? The presence of some solid agglomerates in the pallet immediately caught my eye, which sat firmly on the walls. These, apparently, were the very "harmless" according to the authors of the ill-fated letter "associations of fine particles." But they were clearly less than the volume of the initial sediment in the oil filled in the engine. We also did not notice particles in the filter. This means that the main part of the powder introduced by us into the oil has settled in the channels! This is the reason for the loss of pressure in the lubrication system.
And what did the analysis of the physico-chemical parameters of the oil that worked with this “harmless” powder show? The viscosity of the oil, which was originally 11.2 cSt at 100°C, has increased to 17.9 cSt! That is, the oil, which was originally in the SAE-30 class, jumped to the SAE-50 viscosity class in 40 hours! The acid number increased by more than 2.5 mg KOH/g. Recall that in the last resource examination for 180 engine hours, oils increased their acidity by only 0.75 ... 1.0 mg KOH / g! The base number decreased less, and the deposits on the walls of the crankcase were, although more than usual. Moreover, the oil at room temperature was so thick that it did not want to drain from the walls - we have not seen this before. By the way, the picture that we observed in our experiment was suspiciously reminiscent of the one that was given out by one of the oils during our previous “semi-synthetic” examination.
So, according to some oilers, "harmless" catalyst powder in a relatively short time ruined the oil and finished off the engine. And in this case, alas, even the “capital” will not help him - after all, removing the plugs that clog the oil channels, judging by the structure of deposits in the sump, will be extremely problematic. By the way, some conscious dealers of large automakers who encountered a similar problem changed either cylinder blocks or the entire engine assembly without talking.
The results already clearly show that neither automakers nor car owners are to blame for the troubles that have happened. After all, the thermal instability of some types of oil, leading it to polymerization during volumetric overheating, and the possible presence of an aggressive catalyst deposit in it, which is allowed by some oil manufacturers, are the most serious "punctures" of these companies.
Summing up, while intermediate. Of course, someone would like to hear a loud appeal: they say, do not buy oil from firms A, B and C! And buy D-oil: it never gets sick! But we did not look for the guilty switchman, but investigated the problem. In addition, ten thousand cars can happily run on company A oil, but ten thousand will be the first to get into an unpleasant situation. On the other hand, we technically competently substantiated the inconsistency of the on-duty attacks on the burdock driver. Moreover, we managed to find some possible causes of mass cases of accelerated oil and engine death in general.
We sincerely want to believe that oil and gasoline manufacturers will carefully study our conclusions: all motorists are waiting for this. In the meantime, we recommend using our recommendations on "Methods of Self-Defense", following which you can save the engine in a critical situation.
DROP SAMPLE
On any porous paper (optimally - a piece of a filter for a coffee maker or at least a piece of newspaper) from the oil dipstick of a cold engine, drip a drop of oil. If it quickly spreads over the paper, forming several concentric circles, then the oil is alive. But if it does not want to spread and remains a black drop at the point of fall - urgently replace it!
CAN'T CHECK OIL? FIND A PIECE OF NEWSPAPER!
P.S. It goes without saying that in the course of one of the next examinations of oils, we will separately analyze their resistance to the atrocities we have uncovered. One direction of search is already clear: a new wave of failures was noticed after one of the well-known refineries started working after modernization - after all, a similar catalyst is used in the production of high-octane gasoline!!! But doesn’t it come into the oil with this outwardly quite conditioned fuel? And from another region, information came about an allegedly accidental coincidence of the death of engines according to the scheme we described with the use of fuel containing an exorbitant dose of methanol, which is strictly prohibited in our country. This also needs to be dealt with.
HOT? TRAFFIC JAMS? CHECK THE OIL!
SELF DEFENSE METHODS
To protect yourself from possible trouble, we repeat our recommendations once again:
1. Use only oils purchased from trusted stores. For scheduled maintenance, it is better to come with your oil canister. After buying it, let it stand for a while, and, if possible, see if there is sediment in the canister. Usually the sediment can be seen on the transparent measuring strip on the canister.
2. Make it a rule, even if your engine is not noticed in increased oil appetite, at least once a week to get under the hood and monitor the level and condition of the oil on the dipstick. You should immediately be alerted by a sharp increase in oil consumption, or its sudden dilution, or, conversely, thickening.
3. Be especially attentive to the oil in the summer, when standing in traffic jams for a long time, or during long-distance high-speed hauls. It is then that volumetric overheating of the oil is possible.
4. Adopt the so-called. "drip test" of oil. Its essence and procedure are extremely simple. On any porous paper (optimally - a piece of a filter for a coffee maker, or at least a piece of newspaper) from the oil dipstick of a cold engine, drip a drop of oil. If it quickly spreads over the paper, forming several concentric circles, then the oil is alive. And, if it does not want to spread, remaining a black drop at the place of fall - urgently to the service station to replace it!
Any motorist is well aware that for a long and trouble-free operation of the engine, it is important to periodically change the engine oil. If it has become dark in color, then it's time to replace it with a new one. Professionals recommend replacing immediately after the pressure drops in the motor or the check lights up. If there are serious problems with engine oil, the engine may simply not start. If you don't want your engine oil to turn black, take the car manufacturer's recommendations seriously. The engineers calculated the optimal replacement intervals, on average they are 5000-15000 km of run.
Advice! It makes no sense to spend money on a replacement in a car with low mileage, because this will not affect the quality of the engine, but it guarantees you unnecessary financial problems.
If after 20-30 km after the replacement, the normal color of the oil in the engine disappears, a black color appears, then immediately contact a car service.
Why does it turn black after a change
A similar phenomenon is possible when, when replacing the old composition, you did not completely drain it.
Attention! Even with careful draining of the used mixture, there is a high probability that 1-2 liters of the substance will still remain in the engine.
Some experts advise vacuum draining the oil in order to remove the old from the car engine as much as possible. This technology makes it possible to maximally draw out the spent composition from nodes that are inaccessible to a standard drain, but there is still no 100% removal of the mixture.
Attention! To carry out the replacement of mining using the express method with a vacuum pump, preferably after 5000-15000 km of run, this will ensure a complete renewal of the motor composition.
The best option for updating the oil is the alternation of several drain methods. The replacement algorithm is presented in the following video:
So that the color of the oil in the diesel engine does not change, it is replaced by a standard drain. To do this, the car is put on a lift, mining is removed into a special container, and after cleaning the engine, a new one is poured.
In addition, the oil in the engine takes on the color of gray sour cream in the presence of a dirty filter, if it is not changed in a timely manner. Manufacturers of modern filters have equipped them with special valves, thanks to which you can get rid of the problem of insufficient supply of the substance to the motor even when the filter is clogged. This situation does not cause negative consequences for the motor itself, but filter replacement is still necessary. If you find a black mixture on a dirty dipstick, you need to wipe it with a rag, then recheck. If the pressure will fully comply with the standards, and the color will not change, therefore, there is no reason for alarm.
Among the situations associated with a change in color to black or gray, we note:
Advice! Try pouring a special cleaning agent into the engine, using it to clean the car engine. Use such a composition carefully, otherwise the engine gaskets may be corroded, the pressure in the engine will drop, or the engine will not work at all.
Prevention
In order for the oil to retain its honey-brown color, it is important to fully comply with all the instructions of the car manufacturer: control pressure, change old oil to new oil in a timely manner. Black color is typical for cars that often get into traffic jams, and their owners have to replace them much more often. If problems are identified, immediately carry out a full diagnosis, otherwise the movement by car will be dangerous.
Black oil in the engine
Black oil in the engine causes complete panic for many motorists. They make claims about the quality of the product to the masters of service centers and sellers. In fact, its color can change for various reasons. What are the main causes of blackening? Modern brown engine oil may be due to special additives that reduce friction and change temperature characteristics.
For example, oil in a latte-coloured engine may be due to the use of lye.. This caustic chemical is introduced to neutralize the acid, as well as to prevent deposits (soot, dirt) from appearing in the engine.
There are also special additives that improve the quality of the oil. Without them, “oil starvation” occurs, the temperature regime of the motor is disturbed, it overheats, the oil channels become clogged, the camshaft is disrupted, and the liners rotate incorrectly. With prolonged use of a composition with a high alkali content, it may turn white. If during operation it darkens, this is considered the norm. Professionals say that if, after prolonged use, the engine mixture remains transparent, this is bad. As the main problems, they emit an insufficient amount of oil, which can lead to rapid wear of car engine parts.
Conclusion
In the motor, the movement of oil is carried out in a circle. With the help of a pump, the mixture is pumped from the crankcase, then it is passed through all oil channels. As it moves, it should lubricate all the parts of the car engine, the excess settles, the waste is gradually removed from the engine. Therefore, answering the question of what color the oil should be in the engine, we note that its gradual darkening is considered the norm.
Do not forget that when the engine is running, the oil is heated to a temperature of 120 degrees, resulting in a lubricating effect, accompanied by its darkening. If the substance becomes like fuel oil, after wiping the probe, black stains remain, then it is burning in the engine. The reason for this phenomenon is often the wear of the piston system. Any excess fuel not burned in the cylinders ends up in the oil. It changes its composition, color, becomes unusable. In such situations, a change in the color of the engine mixture is an alarm. There is a decrease in the power characteristics of the motor, fuel consumption increases. If the oil was chosen incorrectly (without taking into account viscosity), the engine may constantly overheat.
For many owners of different brands of cars, it is a mystery why the engine oil quickly darkens. There are several reasons that lead to this result. We will figure out what caused the rapid darkening of the oil, and then we will find out whether it is dangerous for the car or not.
Reasons for the rapid darkening of the oil in the engine
During operation of the motor, the oil gradually changes its color and becomes darker, and sometimes black. For many, this is intimidating and intimidating. In fact, oil blackening is a natural process. Sometimes it goes faster, sometimes slower. But why is it happening at all? Due to the following reasons:
- there is little alkaline additive in the lubricant;
- the piston group is worn out, due to which a large amount of combustion products and fuel oxidation enters the lubricant;
- the motor overheats, causing the oil to boil. As a result, additives are destroyed and the lubricant darkens;
- poor quality lubricant. This usually happens when it is bought in spontaneous markets or from suspicious sellers;
- on the contrary, a high-quality lubricant is used, which quickly and thoroughly flushes a contaminated engine.
The fact is that during engine operation, the oil is constantly moving, while it collects carbon deposits, oxides, and other debris and brings it to the crankcase. Such a lubricating ability of the oil is due to the presence of various additives in it. Depending on the brand of lubricant used, the amount of additives in it will also be different, and each of them will play its role:
- reduction of friction;
- increase in viscosity;
- temperature control and others.
One of the additives used in lubrication is alkaline. It allows you to remove chemicals that have entered the motor, reduces the likelihood of precipitation, removes carbon deposits and dirt. If there is little alkali in the oil used, the engine will wear out faster, a large amount of soot and various deposits will form faster.
Video: reasons for the rapid darkening of engine oil
What is the danger of darkened oil
Some drivers believe: if the lubricant has darkened, then it has used up its resource and it is necessary to replace it. However, not everything is so clear-cut here.
If for some reason you really used cheap low-quality oil, then when it gets dark, it is better to replace it. The use of such a lubricant will quickly clog the engine with dirt, soot and other deposits. As a result, its power will decrease and fuel consumption will increase. If you use such oil for a long time, then the motor can become very dirty and you will have to overhaul it, and this will entail serious costs of both time and money.
On the other hand, a quickly darkened high-quality oil may indicate a poor condition of the engine and its severe contamination. Therefore, first of all, it is necessary to rely not only on the color of the lubricant, but also on the engine resource, the age of the car, the frequency and quality of car care, driving conditions, and the quality of gasoline.
Preventive measures to prevent the rapid darkening of the oil
During engine operation, even the highest quality and most expensive oil will gradually darken. To avoid its rapid darkening and pollution, you must adhere to the following rules:
- use only high-quality oil and buy it only in specialized stores and from trusted sellers;
- for cars with high mileage, do not use low alkalinity grease;
- monitor the condition of the engine and, if necessary, carry out repairs in time. It is motor malfunctions that most often cause rapid contamination of the lubricating fluid;
- when changing the oil, flush the engine. Many owners ignore this step. You can perform this procedure both at the service station and on your own.
Engine flush features:
Some craftsmen flush the engine with kerosene or diesel fuel. Although they also help clean the motor, they have poor lubricating properties, unlike flushing fluid. Such amateur performance can lead to failure of the motor, so it's better not to risk it.
Video: how to flush the engine
Answering the question of whether black oil in the engine is “good” or, conversely, “evil”, we can say that this is rather good. Gradually darkening grease indicates that the motor is well flushed. But if it gets dark very quickly, then you should pay attention to the condition of the engine.
