Everything You Need to Know About Motor Oil

Frequently Asked Questions About Motor Oil

What Are the Functions of Motor Oil?

The primary functions of motor oil are;

·       It minimizes friction to prevent wear.

·       It helps cool engine components operating at high temperatures, preventing deformation from heat.

·       It cleans engine parts by carrying dust and dirt to the oil filter.

·       It fills the gaps between rings, pistons, and cylinders, preventing gas leakage and increasing efficiency.

What Are the Types of Motor Oil?

Motor oils are divided into three categories based on their production methods: mineral, semi-synthetic, and fully synthetic.

Mineral Oils

Mineral oils are produced by distilling crude oil and adding additives such as detergents, viscosity improvers, and anti-wear agents.

Fully Synthetic Oils

Synthetic oils are produced in a laboratory environment through entirely chemical processes.

Semi-Synthetic Oils

These are obtained by blending mineral and synthetic oils. Typically, semi-synthetic oils are produced by adding 20-30% synthetic oil to 70-80% mineral oil.

What Are the Differences Between Mineral and Synthetic Oils?

·       The most significant difference between synthetic and mineral oils is their resistance to temperature. Synthetic oils are more fluid at low temperatures. Due to their low evaporation coefficient, they experience less oil consumption at high temperatures.

·       Synthetic oils are more expensive than mineral oils because their production requires intensive chemical processes and their raw materials are more costly.

·       The lifespan of fully synthetic motor oil is longer compared to mineral oil. In the long run, synthetic oils are more economical and environmentally friendly.

·       Synthetic oils, which are more durable and expend less energy on friction, deliver superior performance.

Does Motor Oil Affect Fuel Consumption?

When you use high-quality motor oil, you save energy otherwise lost to friction, which in turn reduces your fuel consumption.

Does Motor Oil Affect Performance?

Because motor oils prevent wear and reduce the energy spent on friction, you can effectively transfer your engine's power to the road, thereby enhancing your car's performance.

What Are the Benefits of an Oil Change?

Delaying an oil change causes the oil, responsible for cleaning and protecting your car's engine, to become contaminated and fail to perform its duties. Therefore, regular oil changes are crucial. Renewing the motor oil extends the engine's life, boosts the car's performance, and helps you save on fuel.

How Often Should Motor Oil Be Changed?

The ideal oil change interval can vary depending on your car's model, the type of oil you use, and the mileage. As a general guideline, older cars should have their oil changed every 5,000 kilometers, while newer cars can go up to 20,000 kilometers. You should also remember to replace your car's oil filter during the oil change.

How to Check Motor Oil?
You must have your motor oil checked when the oil pressure warning light on the dashboard illuminates. It is also possible to check the oil level yourself by parking the car on a level surface and removing the dipstick. The ideal oil level is between the maximum and minimum marks.

·       Besides a low oil level, the oil warning light may illuminate for the following reasons;

·       Oil pump failure

·       Faulty oil pressure sensor

·       Blockage in the oil system

Key Tips for Changing Motor Oil

Where is motor oil added?

If you are adding motor oil yourself, you can do so through the cap on the valve cover.

How many liters of motor oil should be added?

The amount of motor oil to add varies depending on your car's model and engine. For example, a 3-cylinder engine may require 3.5-4 liters of oil, while a 6-cylinder engine might need 6-7 liters.

What happens if there is too much motor oil?

When you overfill the motor oil, it can enter the combustion chamber, causing your car to emit oil and smoke from the exhaust.
Excess oil wears down the piston rings and valve seals, leading to engine blow-by.

How is motor oil topped up?

Sometimes your car's oil level may drop; the most significant reason for this is the engine burning oil.

 

How can we tell if the engine is burning oil? If the exhaust smoke is blue, if air blows out when the oil cap is opened, or if the oil level on the dipstick remains below the ideal mark, your engine is likely burning oil. Smoke coming from the dipstick tube can also indicate oil consumption. So, how can you prevent the engine from burning oil? To prevent your engine from burning oil, you should have the oil level checked regularly and avoid running your car at consistently high RPMs.

If you want to top up the motor oil yourself, you should add it little by little and check the level on the dipstick. It is also important that the oil you add is the same type as the existing oil.

What Does the Color of Motor Oil Indicate?

Darkening motor oil does not indicate a problem with your engine or the oil itself. On the contrary, dirty oil shows that it is performing its function. In this case, simply changing your motor oil and filter will suffice.

Are Motor Oil Additives Beneficial?

You may have noticed that in addition to motor oil, oil additives are frequently used by drivers. But are these additives, which promise benefits like fuel savings and performance boosts, truly beneficial? Experts state that modern motor oils already contain all the necessary components for your car, making additives unnecessary. Furthermore, they warn that in the long term, these additives could do more harm than good to your engine.

Technical Specifications of Motor Oil

Motor Oil Viscosity

In its simplest terms, viscosity is the measure of an oil's thickness. The term viscosity, used for all fluids, refers to resistance to flow. Let's clarify what viscosity is with an example. As you know, honey is thick and water is thin; therefore, we can say that honey has a higher viscosity than water. Similarly, if an oil is thick, its viscosity is high; if it's thin, its viscosity is low.

Oils with very high viscosity may not reach all parts of the engine at low temperatures due to their poor fluidity.

Conversely, oils with very low viscosity can thin out at high temperatures and lose their protective properties.

Single-Grade and Multi-Grade Oils

Motor oils are divided into two types based on the air temperature ranges they serve: single-grade and multi-grade oils. You may also see single-grade oils referred to as single-season oils, and multi-grade oils as all-season oils.
When selecting a motor oil based on its viscosity range, you should consider the lowest temperature in winter and the highest temperature in summer.

What Are the Differences Between Single-Grade and Multi-Grade Oils?

While multi-grade oils adapt to changing temperature values, the structure of single-grade oils remains the same at all temperatures. Therefore, multi-grade oils offer several advantages;

Multi-grade oils are more fluid in cold weather and thicker in hot weather.
Multi-grade oils provide greater fuel economy.
Providing superior protection in all weather conditions, multi-grade oils are a safer choice.

Viscosity Classification of Motor Oils

Motor oils are classified according to their fluidity—or viscosity values—at low and high temperatures. In the SAE (Society of Automotive Engineers) classification, the lower the number, the thinner and more fluid the oil. For example, an SAE 10 oil is more fluid than an SAE 50 oil.

In the SAE classification, the letter 'W' indicates that the motor oil is a winter-grade oil. If the letter is not present, you can understand that it is a summer-grade oil. Winter motor oil is produced with a lower freezing point, while summer motor oil has a higher boiling point.

Oils designated with notations like “SAE 15W–50” are suitable for all-season use.

Summer Motor Oils: SAE 10, SAE 20, SAE 30, SAE 40, SAE 50
Winter Motor Oils: SAE 5W, SAE 10W, SAE 15W
All-Season Motor Oils: SAE 10W-40, SAE 15W-50, SAE 15W–50

What Does the Motor Oil Performance Class Indicate?

You can understand the performance of a motor oil from the API and ACEA values written on its packaging.

API Performance Class
According to the API (American Petroleum Institute) classification, the letter "S" indicates the oil is for use in gasoline engines, while the letter "B" indicates it is for use in diesel engines.

For gasoline engines, oils are classified by performance into 12 categories: SA, SB, SC, SD, SE, SF, SG, SH, SJ, SL, SM, and SN. Oils in the SA, SB, SC, SD, and SE classes were used in cars manufactured between 1930 and 1979. Their use in modern cars is not recommended. Today, motor oils in the SJ, SL, SM, and SN performance classes are more commonly preferred.

ACEA Performance Class

According to the classification developed by the European Automobile Manufacturers' Association in 1996, the letter "A" indicates use in gasoline engines, "B" in light-duty diesel cars, and "E" in heavy-duty diesel cars. The number following the letter determines the oil's performance level. For example, in gasoline engines, A1 is used for fuel economy, while A5 offers high performance.

 

How to Choose the Right Motor Oil?

The most important aspect of motor oil selection is choosing the most suitable oil for your car. In light of all this information, how can we select the right motor oil for our car? First, you must not forget to consider the viscosity and performance classification values specified in your car's owner's manual. Other key points to consider when choosing motor oil are;

1. Select motor oil based on your engine's technical specifications.

High-RPM, new-generation engines: Have smaller oil clearances, so oils with a low SAE number can be used.
Mid-RPM engines: As oil clearance increases slightly, oils with an average SAE number can be used.
Low-RPM engines: Have larger oil clearances, so oils with a high SAE number may be preferred.

2. Choose the oil appropriate for your car's model year.

For gasoline engines; SJ was developed for cars manufactured in 2001 and earlier; SL for cars manufactured in 2004 and earlier; and SM for cars manufactured in 2010 and earlier. SN is the latest and most advanced motor oil class for cars manufactured after 2011, and it is also backward-compatible with cars made before 2011.

For diesel engines, the CH-4, Cl-4, Cl-4 PLUS, and CJ-4 service classes are suitable for the needs of modern engines. CJ-4 is the most advanced motor oil for diesel engines.

3. Consider the ambient temperature when selecting motor oil.

SAE 5W-20: Suitable for engines operating between -8° and -30°.
SAE 5W-30: Suitable for engines operating between -30° and 16°.
SAE 10W: Suitable for engines operating between -18° and 16°.
SAE 10W-30: Suitable for engines operating between -18° and 40°.
SAE 10W-40: Suitable for engines operating between -18° and 40°.
SAE 20W-20: Suitable for engines operating between -8° and 40°.
SAE 20W-40: Suitable for engines operating between -8° and 40°.
SAE 20W-50: Suitable for engines operating between -8° and 40°..