The question of why the vehicle burns oil is one of the most frequently researched topics, especially by owners of high mileage or old vehicles. Oil burning is a serious problem that affects the efficiency of engine operation. Engine oil is used to reduce friction, protect parts and make the engine run more efficiently.
What is Oil Burning?
Oil burning is when oil leaks from the engine oil system into the combustion chamber, where it burns together with the air-fuel mixture. This is usually indicated by blue smoke coming out of the exhaust. Oil burning should not occur during the natural operation of the engine. If a vehicle is constantly running low on oil at regular intervals and this is happening without any visible leakage from the outside, it is most likely that the engine oil is burning.
The problem of burning oil can be caused not only by the wear and tear of engine components, but also by improper oil use, poor maintenance and bad driving habits. Not only does this cause economic damage to the engine, but in the long run it can also lead to more harmful emissions into the environment. It is possible to prevent this problem with early diagnosis and correct intervention.
Why does engine oil run out?
One of the main causes of engine oil loss is worn parts of the internal combustion engine. Over time, piston rings, cylinder walls or valve rubbers can wear out, causing oil to leak into the combustion chamber. Running out of oil means that the engine is not sufficiently lubricated, which opens the door to serious engine failures. If the oil is not replaced in a timely manner, irreversible damage such as engine bearing seizure can occur.
In addition, turbocharger malfunctions, gasket leaks or clogged oil filters are among the main causes of oil deficiency. For example, due to a malfunction in the turbo system, oil can get into the cooler or intercooler pipes. In such cases, the oil level drops even if the vehicle does not burn oil. For this reason, the oil level of the vehicle must be checked every 1000 km. Another issue to be considered at this point is to use the type of engine oil recommended by the manufacturer.
Causes of Oil Burning in Vehicles
The basis of oil burning in vehicles is usually the wear and tear of engine parts. However, this is not limited to mechanical reasons. The use of poor quality engine oil, extreme driving conditions, regular exposure of the engine to high temperatures also trigger this problem. In particular, worn rings cannot ensure a proper seal between the engine oil and the cylinder and cause the oil to pass into the combustion chamber.
Another factor that draws attention among the causes of oil burning is improper maintenance practices. For example, delaying oil change intervals or not choosing oils with the appropriate viscosity can exacerbate the problem. The problem of oil burnout is sometimes difficult to recognize because oil loss can occur without leaving a visible leak. The following technical causes in particular should therefore be examined closely:
Worn Piston Rings and Cylinder Walls
Piston rings provide the seal between the piston and the cylinder wall during the up-and-down movement of the piston in the cylinder. However, over time, these rings can wear out and no longer fulfill their function. Worn rings allow engine oil to pass into the combustion chamber. This leads directly to the problem of oil burning. Burning oil here causes both a drop in the oil level and blue-colored smoke from the exhaust. This is especially common in high mileage vehicles.
The wear of the cylinder walls also leads to the mixing of engine oil with the fuel-air mixture. In this case, the engine cannot run efficiently as combustion is carried out with the oil. Engine power can drop, fuel consumption increases and visible smoke can be emitted from the exhaust. Depending on the extent of the wear, ring replacement may be sufficient, while in some cases a complete engine reconditioning may be required.
Hardening of Valve Tires
Valve tires are responsible for preventing oil leakage in the engine's valve system. These tires harden over time by being exposed to heat, pressure and the chemical effects of oil. Hardened or cracked valve rubbers become unable to fulfill their sealing function and engine oil leaks into the combustion chamber. This is one of the most common causes of oil burning in vehicles.
Especially when the engine is started when it is cold, a short period of blue smoke from the exhaust may indicate that the valve tires have deteriorated. Such symptoms are usually noticed during the first start-up in the morning. Valve train replacement is carried out by opening the top cover of the engine and is less expensive than other parts. However, if neglected, it can also affect the overall performance of the engine over time.
Turbo Failures and Oil Leakage
Turbocharged engines provide a performance boost and also run on engine oil. The bearings in the turbo unit are cooled and lubricated with oil. However, when a malfunction occurs in the turbo system, the oil can leak into the intercooler or exhaust line. This leaking oil burns together with the air-fuel mixture and the vehicle develops an oil burning problem.
In turbo failures, thick blue smoke is usually observed from the exhaust. There is also a loss of performance and a sudden drop in oil level. If such an oil leak is not recognized in a short time, it can cause huge costs for both the turbo and the engine. Periodic checks and oil changes should not be neglected for early diagnosis of malfunctions in the turbo system.
Using Wrong or Poor Quality Engine Oil
Engine oil selection is a critical issue for the health of the engine. Engine oils with the viscosity and quality specified by the manufacturer must be used. Oils with the wrong viscosity cannot create sufficient pressure inside the engine or may leak between parts. This can cause the oil to reach the cylinders and burn, leading to oil burnout.
In addition, oils of poor quality, with insufficient additives or oxidized over time cannot form a protective layer inside the engine. This accelerates the wear of engine components. Especially the use of counterfeit or expired oils can cause serious malfunctions. When choosing engine oil, it is very important to prefer products that comply with API/ACEA standards and have brand assurance to prevent such problems.
Engine Overheating
Engine overheating can cause the seals to loosen or harden, allowing oil to leak into the combustion chamber. A malfunction in the cooling system (e.g. radiator leak, water pump failure or thermostat failure) upsets the engine's temperature balance. An overheated engine can lose component tolerances, leading to leaks.
Continuous operation of the engine at high temperatures reduces the viscosity of the oil and causes it to lose its protective properties. This leads to direct contact and wear of the engine components and eventually to oil burn. If the temperature gauge is constantly at a high level, this should never be ignored and a service center should be contacted immediately.
Aging of the Vehicle and High Mileage
As the usage time and mileage of the vehicles increase, the parts inside the engine naturally wear out. On average, the probability of burning oil increases considerably in vehicles with more than 150,000 kilometers. This is due to the wear and tear caused by time and use, no matter how high quality the engine design is.
Incorrect practices in high mileage vehicles also accelerate this process. For example, mistakes such as disrupting periodic maintenance, not changing the oil for a long time or using the engine at high speed when the engine is cold negatively affect engine health. Therefore, as the age and mileage of the vehicle increases, the engine should be checked regularly and the oil level and quality should be reviewed frequently.
What Are the Symptoms When a Vehicle Burns Oil?
A vehicle that burns oil shows some obvious signs. The main one is blue smoke coming out of the exhaust. This smoke occurs when engine oil is burned in the combustion chamber and is more noticeable, especially during the first start-up in the morning. In addition to the blue smoke, the lack of oil can be detected during user checks. Especially if there is a loss of half a liter or more every 1000 km, there is a high probability of burning oil.
Another symptom is reduced engine performance and increased fuel consumption. An engine that burns oil cannot run efficiently, which causes more fuel to be consumed. An increase in engine noise, irregular operation and frequent warning lights on the oil gauge are also important signals. These symptoms should not be ignored and should be checked by a service center.
What to do for an Oil Burning Vehicle?
First of all, the source of the oil burning problem must be correctly identified. For this reason, the vehicle must be checked by a specialized service center. The necessary parts should be replaced to repair problems such as piston rings, valve tires, turbo or gasket failures. These operations can be done by opening the engine according to the structure of the engine and the cost may vary.
If there is a problem with the quality of the oil or the filter, changing the oil and oil filter may solve the problem. Choosing a quality oil with the correct viscosity protects the engine in the long term. In some cases, temporary solutions can be applied by cleaning carbon deposits with in-engine cleaning fluids. However, such applications are usually temporary and require mechanical intervention for permanent results.
Maintenance Tips to Prevent Car Oil Burning
In order to avoid oil burning, regular engine maintenance should be performed first. The maintenance intervals recommended by the manufacturer should be followed and oil changes should not be interrupted. Especially depending on the conditions of use of the vehicle (urban, heavy traffic, high speed use), maintenance periods can be shortened even more. Engine oil level should be checked regularly.
Choosing the right oil and filter is critical for engine life. Products of quality brands with the viscosity recommended for the vehicle should be preferred. Likewise, the filter should also comply with original or equivalent quality standards. Driving habits can also affect oil burning. Avoiding high speeds when the engine is cold, not idling for a long time and preventing the vehicle from overheating are useful in this regard.
Does Oil Burning Problem Affect Vehicle Value?
Yes, the oil burning problem directly affects the second-hand market value of the vehicle. Because this kind of problem means a big risk for potential buyers. A vehicle that burns oil can be a confidence shaker for buyers as it shows that the engine is worn out. Therefore, there may be a serious price drop in vehicle sales.
In addition, such problems are clearly revealed in the expertise reports. If there is a sign of oil burning in analyzes such as engine compression test and exhaust emission measurement, this is reflected in the expertise note as “engine oil is burning”. This complicates the sales process. Fixing the problem is essential for both preserving the value of the vehicle and safe driving.
