Engine oil consumption is determined depending on the amount that burns out in the engine. Excessive consumption of engine oil can indicate either poor quality (the lubricant then burns out excessively) or a malfunction of the engine itself (leakage occurs, most often through valve seals and oil scraper rings). Everything will depend on the specific numbers and additional symptoms that may appear when the lubricating fluid is lost.
Where does it disappear to? 5 reasons
Frenzy.
Piston rings require constant lubrication.
The first compression ring periodically leaves a film of oil on the surface of the cylinder, which at high temperatures begins to partially burn off. In the total balance of oil losses in the engine, waste in the cylinders is up to 80%. On new engines, waste is always higher than after break-in. burns intensely ,
the characteristics of which often do not correspond to those declared.
As quality oil is added to the engine, consumption will drop. oil with low operating viscosity
behaves similarly : it burns out faster than a more viscous one.
Engine oil consumption in the engine is normal
So, let's start with the fact that all engines consume motor oil to a greater or lesser extent. This occurs taking into account the design features of the internal combustion engine, namely due to the urgent need to lubricate the components and parts of the CPG. In other words, the main loss of lubricant occurs as a result of the need to supply lubricant to the cylinder walls.
This area in the engine is a heat-loaded area. For this reason, partial evaporation and combustion of the lubricant occurs. Also, some of the oil is not removed from the cylinder walls by the piston rings, as a result of which the remaining lubricant burns along with the fuel in the combustion chamber.
As a rule, in modern engines the declared oil consumption is, on average, from 0.1 to 0.3% of the total fuel consumption that was spent to overcome any part of the journey. It turns out that if the car has traveled 100 km, and the consumption is 10 liters of fuel, then the norm will also be to consume, on average, 20 grams of oil.
It turns out that lubricant consumption can be considered acceptable if it does not exceed about 3 liters. per 10 thousand kilometers traveled. It is also important to understand that the consumption rate will greatly depend on the type of engine, the degree of its boost, etc.
For example, for many gasoline naturally-aspirated internal combustion engines, the norm is around 0.1%. On gasoline turbo engines, the consumption rate is noticeably higher. As for a diesel engine, the declared lubricant consumption rate will be greater than any gasoline equivalent and ranges, on average, from 0.8 to 3%. The indicated 3% is consumed by forced turbodiesels with two turbines, etc.
You can also separately mention rotary motors, which are particularly prone to lubricant consumption. Such units (taking into account their fully operational condition) consume about 1-1.2 liters of oil per 1000 km. mileage For reference, the manuals for different engines indicate that the norm for oil consumption for waste is 1 liter per 3 thousand km traveled, that is, about 3 liters per 10 thousand km.
At the same time, manufacturers also note that consumption directly depends on both the technical condition of the internal combustion engine and the operating characteristics of a particular vehicle (load on the unit, speed, etc.)
Blue smoke
When buying a car, remember that naturally aspirated engines have lower oil consumption than supercharged ones. And if we are talking about used cars, know that the presence of increased consumption cannot be determined by eye. Experienced people even clean the exhaust pipe before selling. You need to contact specialists. But if blue smoke appears from the chimney, then this is an indicator of an exorbitant oil appetite. You can't hide it.
Have a nice trip - and less “oil” problems!
- Find out how to choose motor oil for the summer here.
How much is normal oil consumption?
What determines engine oil consumption and how to reduce it
As mentioned above, oil is consumed in any engine, since the oil film on parts to protect against dry friction burns in the chamber along with the fuel charge. If we add to this the natural wear and tear of the internal combustion engine during operation, then lubricant consumption further increases.
However, it becomes quite obvious that 3 liters of oil per 10 thousand km. for a small car with an in-line aspirated engine this can be considered a high consumption, while for a powerful unit with a large displacement this is a completely acceptable figure. Practice shows that even if the engine begins to “eat” more oil than normal, it is more economically profitable to simply add lubricant than to immediately overhaul the engine just because of increased consumption.
The fact is that at many service stations, technicians prefer not to diagnose a separate cause of increased oil consumption, but immediately offer the owner to make major repairs. It is important to consider that such expensive repairs are not always necessary.
- First of all, lubricant consumption may increase due to oil leaking from the engine. In this case, it is enough to replace the gaskets and seals. Generally, you need to pay attention to the valve cover gasket, cylinder head gasket, front and rear crankshaft oil seals, camshaft oil seals, valve seals, etc.
In various situations, lubricant can flow along the external surface (leak out) and also penetrate into other systems. For example, if oil is leaking between the transmission and the engine, the crankshaft seal is at fault, and a puddle may form under the car.
If the cylinder head gasket turns out to be problematic, there may not be any leaks on the outside, the engine will be dry. In this case, the lubricant will enter the coolant, the coolant will become cloudy, the oil in the engine will also begin to foam, and an emulsion will appear under the oil filler cap and on the dipstick.
- If oil is actively consumed in the engine through waste, blue oily smoke will come out of the exhaust pipe. In this case, especially compared to a leak, it is much more difficult to determine the cause without disassembling the engine.
However, even in such a situation, you can try to fight the waste before agreeing to repairs. First of all, lubricant consumption depends on the operating mode of the motor. In other words, driving at high speeds leads to an increase in temperature and loads, the oil thins out, is less easily removed by rings from the cylinder walls, burns out, etc.
- It is also important to understand that the lubricant may not be suitable for the engine according to certain parameters. This means that you need to know which oil to choose for the engine and what features need to be taken into account.
If the engine is worn out, then at the same time you need to take into account the features of selecting oil for engines with high mileage. In a nutshell, the reduced viscosity material forms a thin film that the oil scraper rings cannot remove from the walls. If the lubricant is thick, then the film is very thick, and the rings cannot remove such a layer in full.
Taking into account the above, it becomes clear that you need to use the most suitable oil both in terms of tolerances and high temperature viscosity index. For example, from the list of recommended lubricants in the manual, you need to select a product with a higher viscosity compared to what is currently filled.
You can also switch from synthetics to semi-synthetics, which in some cases also allows you to reduce lubricant consumption. The main thing is that such semi-synthetics are allowed for use in a specific internal combustion engine and comply with the recommendations of the engine manufacturer.
- Oil seals (valve seals, oil seals) are also an element, problems with which increase the oil appetite of the unit. At the same time, on many internal combustion engines, the caps can be replaced without removing the cylinder head; the cost of the spare part is very low. In some cases, lubricant consumption after replacement is significantly reduced.
The main reason for failure of valve seals is their drying out and hardening, since the elements are made of rubber. Also, the seals can be affected by oil that is unsuitable for the engine, which has an aggressive effect on the rubber.
We also recommend reading the article about what engine additives exist to reduce oil consumption and reduce smoke. From this article you will learn about the types and features of the operation of such additives in motor oil.
- Symptoms of worn piston rings are often similar to their failure. If in the first case the rings need to be changed, that is, disassembly and repair of the internal combustion engine will be required, then in the second case the piston rings can be decarbonized.
Simply put, the accumulation of soot and coke does not allow the ring to move in the groove, that is, the rings are stuck. Reduced mobility means that the ring does not perform its function, the oil is poorly removed from the walls and burns out in the combustion chamber.
To solve the problem, there are flushes that are poured into the lubrication system. Flushing oils can also be used. A radical method is when a special composition is poured into the spark plug wells to decarbonize the piston rings.
Each of the solutions has both its pros and cons, however, for a worn engine, in many cases it is possible to reduce lubricant consumption and extend the life of the engine until overhaul.
- An increase in crankcase pressure also causes excessive consumption of lubricant. In simple terms, high crankcase gas pressure causes oil to end up where it shouldn't be.
As a result, the lubricant enters the cylinders through the intake, after which it burns in the engine along with the fuel. In such a situation, it is necessary to diagnose and clean the crankcase ventilation system.
- Problems with the turbocharger also lead to lubricant leaks in the supercharger area, oil also entering the cylinders through the intake, etc. The solution requires diagnostics and repair of the turbine. As a last resort, you can replace the turbocharger, and the lubricant consumption will also decrease.
Oil starvation - main causes and consequences
Oil starvation is a condition of a car engine when a number of components and assemblies receive too little oil for their stable operation. There are three reasons why this problem occurs:
- Lack of oil in the engine. Changing engine oil is an essential part of regular maintenance.
- Skipping the time to change the car oil. It is customary to change engine oil after every 15,000 km, however, given the condition of the engine and the conditions in which the car is operated, the replacement can occur within a shorter period of mileage.
- Low quality oil. To save money, car owners sometimes buy it from unreliable places, which leads to engine problems.
- With slight starvation, the lubricant level on the dipstick is slightly below the minimum, but in this case there are no obvious symptoms of starvation. A number of automakers even leave such a “gap.” Moreover, even if the oil level is less than the minimum, there may be no deviations at all on the engine side.
The result of engine oil starvation is directly determined by the duration of starvation and the criticality of the situation:
- 1st stage of fasting . In this situation, a clear symptom arises, which consists of the car twitching when driving and when changing speed. Even at the 1st stage of fasting, blue smoke begins to emerge from the exhaust pipe. When you see blue smoke, you should conclude that the piston rings of the engine are stuck, which suggests decoking.
- 2nd stage . The above-mentioned annular occurrence is quite easily eliminated, however, if the symptoms of oil starvation are ignored or if the engine wears too quickly, problems associated with the camshaft appear.
- 3rd stage . In the event of an almost complete lack of oil in the engine, problems can affect, in addition to the camshaft, also the crankshaft and engine pistons.
How to calculate consumption
Oil consumption is calculated as a value equal to the volume of lubricant consumed to burn 100 liters of fuel. That is, to determine the norm, it is not the mileage of the car that is taken into account, but the amount of fuel consumed. This figure will be more accurate, since fuels and lubricants are consumed not only while driving, but also when forced to stand idle in traffic jams. Lubricant consumption is determined in different ways, for example using the formula:
Qр = V/(P × k), where:
- Qр – capacity of the vehicle lubrication system;
- P – amount of fuel consumed;
- k is a coefficient that takes into account the wear of the piston group. For diesel engines this figure is taken equal to 1.25, for gasoline engines - 1.15, with turbocharging - 1.3.
Conclusion
You should not neglect the tolerances of motor oils, mix different types of products, or fill in fuels and lubricants of questionable quality.
To increase engine life, it is necessary to strictly follow the rules for adding oil. Its normal consumption is an important condition for the correct operation of the power unit. Lack or excess of lubrication will negatively affect the functionality of the engine.
During the operation of the car, its owner must monitor oil consumption, and when it reaches a critical value, contact a service station, where specialists will carry out diagnostics and find a way to fix the problem.
The “Oil Pressure” icon is on - reasons
The indicator is inactive when the engine is running and there is sufficient fluid volume. When the oil pressure light comes on, the lubricant level is already critically low. When checking with a dipstick, there may be no traces of liquid left on it at all. Other reasons are low pressure in the engine oil system, failure of the oil level indicator.
The first thing the driver must do is stop the car . Otherwise, after a few kilometers the engine will “die”.
Insufficient fluid level
When the fluid level drops below the permissible limit, the corresponding sensor lights up. The indicator is constantly on. Sometimes the indicator will light up for a few seconds and then go off. This happens when a car is driving up or down the road. Oil overflows to one side of the crankcase, the sensor may react.
Solution to the problem: measure the liquid level and add the required volume.
Incorrect viscosity
The problem is typical for low temperature viscosity. When the lubricant thickens in the cold, the system does not pump it, the pressure drops, and the indicator reacts accordingly. The viscosity of the lubricant changes with use, the oil becomes contaminated and thickens, accordingly, the sensor will indicate the problem.
Solution: use oil of the viscosity recommended by the manufacturer. It is also necessary to change the lubricant in a timely manner; the frequency is indicated in the technical documentation.
Low quality filter
A filter whose design does not have a check valve or does not fully perform the specified function is considered to be of poor quality. It is this that prevents the oil from completely flowing out of the filter. When the fluid completely drains into the oil pan, when the engine starts, the system builds up pressure for some time, as a result of which the parts quickly wear out. The problem is signaled by an indicator that turns on when the car starts, and goes out after a few seconds or minutes.
Dirty filter
As the oil filter becomes dirty, the pressure in the system decreases, the load on the oil pump also increases, and it wears out quickly. The problem will be indicated by an indicator that is active at low or idle speeds.
Solution to the problem: change the oil regularly, use a fluid of suitable viscosity, and also change the oil filter at the intervals specified by the manufacturer.
Oil level sensor is faulty
There are two options. The first is that the light is constantly on because the sensor slider is stuck. This happens when the oil level is too high and the slider “sinks” in it.
The opposite situation happens - the sensor does not respond to the oil level. This means that when the liquid level is critical, the indicator will not light up. You can determine the actual oil level manually using a dipstick.
BMW
Among Bavarian engines, N series power units produced in the 2000s showed high oil consumption.
The 3 Series and even the 5 Series sedans were equipped with four-cylinder turbocharged units N45 and N46. Later they were used on X3 crossovers. For these engines, by 80,000 km, the valve stem seals wore out. To reduce friction losses, the pistons were made T-shaped, which left little room for the O-rings.
Why do we need motor oils with zero viscosity? More details
Reasons for overspending
Lubricant consumption in the engine can be natural or unnatural. The first occurs when the engine is running, which requires a certain amount of lubricant to function properly.
But there are other reasons that influence the increase in consumption above the norm.
- Excess. Many car owners do not know or simply forget that it is impossible to pour excess lubricant into the engine crankcase. Also, sometimes this happens when the rules for changing the lubricant are not followed. If there is more oil than normal, it begins to push itself through the holes inside the engine. As a result, volatilization occurs through the ventilation system and more. You have to top it up again after a while.
- Cheap lubricant. Each car owner decides independently which oil to use for the engine. Basically, it is important to take into account the characteristics of the liquid, but many people forget about quality. Low-quality lubricants have minimal viscosity and tend to evaporate quickly.
- Increased load on the engine. If you are a fan of fast and aggressive driving and constantly load the engine, then the lubricant consumption will increase. Operating conditions, soil type, weather conditions, vehicle load, etc. play an important role.
- Air temperature. An extremely simple rule applies here. The higher the ambient temperature, the more oil will be consumed. Therefore, lubricant is added more often in summer than in winter.
- Factor of physical losses. This phenomenon is often associated with problems with the oil filter or poor sealing of the power plant. Quite often, the cylinder head gasket stops functioning normally, and the tightening of the mounting bolts becomes loose.
- Violation of the lubricant replacement regime. The frequency of oil changes for each car and engine is individual, as it depends on a large number of factors. But it is not recommended to change the lubricant less than once per 10 thousand kilometers. This is usually done after 5-7 thousand kilometers. If you do not follow these recommendations, old worn-out oil will not only be consumed more actively, but also create serious problems for your engine.
Honda Civic Candy JDM › Logbook › Oil change based on engine hours/fuel consumption. Calculation formulas.
I consider this approach to changing oil to be more reliable in terms of its operating time than replacing it by mileage, which is often so incorrect that discussions of such a plan as “how often to change the oil” cause confusion, as there is no clear criterion for engine operating time, despite the factory’s recommendations to reduce oil in difficult conditions timing... this is also approximately... Nowadays a car costs more due to traffic jams, and in winter the lion's share of the oil's life is burned by warming up and rattling in the cold! therefore, mileage becomes secondary, although as a means of measurement, it should also not be thrown off the chart, because someone rushes along the roads for days, such as taxi drivers, their mileage is a rather objective value.
“Research shows that in large cities the average speed is 20-30 km/h. During the same time “outside the city,” the car travels 3-4 times the distance, and the engine does approximately the same amount of work. Because of this feature, in city traffic jams, motor oil exhausts its service life much earlier, losing its properties and reducing the life of the engine.”
at one time on the BMW 7 there were LEDs on the dashboard, 5 green, yellow and red, the green ones go out one at a time every 2000 km, for a total of 10,000 oil changes, but the note said that it also depends on the driving style. It turned out that if you are a simple, calm rider, the yellow LED will light up after 10,000 km, and if you are a racer and know just to press on the gas, then the display will signal an oil change and the next maintenance much earlier. This system apparently calculated the load on the engine based on engine speed, which is also not unimportant!
In this regard, in many modern foreign cars, the electronics, based on a combination of operational factors, even taking into account the number of start-stops, determines when the oil needs to be changed.
But what should we do, who are interested in the life of the engine and oil, but do not have the opportunity to conduct such full control?
At one time I bothered with this issue on the basin and installed the engine hours taken from an imported truck, and my calculations at that time were confirmed, the engine hours accumulate much faster than kilometers! I decided to return to this topic after accidentally stumbling upon this watch in the garage
