
What is Motor Oil?
Motor Oil is the first shield of defense engines have! Keeping your motor function for long times would be impossible without motor oil.
What Is in Motor Oil?
Motor oil consists of base oils and additives that work together to protect the engine and enhance its performance. The base oil, which makes up 70-90% of the formula, while additives are added to enhance performance provide extra protection.
Engine oil quality and specifications starts from base oil. Lubrication is determined by the ability of the motor oil to reduce friction. Additives role is to improve efficiency partially therefore, the main rule always is
High-quality lubrication starts with the finest base oil.
Base oils are classified into:
- Conventional
- Synthetic
- Synthetic blends (Semi-Synthetic)
Conventional oils are refined from crude oil and provide basic lubrication. Labs are the source of Synthetic oils. Both synthetic and conventional oils share a similar chemical foundation, but their physical properties set them apart. Molecular structures differences influence viscosity, temperature resistance, and overall car engine protection. Impurities on the other hands also affects how well
Motor Oil Additives
Additives enhance motor oil by optimizing lubrication, reducing wear, and maintaining engine cleanliness. They improve the oil’s thermal stability, viscosity, and resistance to breakdown under extreme conditions.
- Detergents: Prevent deposit buildup and neutralize acidic byproducts from combustion.
- Anti-wear Agents: Minimize metal-to-metal contact by forming a protective barrier on surfaces.
- Viscosity Modifiers: Maintain oil consistency across temperature extremes. Polymers like olefin copolymers and polyisobutylene expand and contract with temperature changes, preventing excessive thinning in heat and thickening in cold conditions.
- Antioxidants: Slow down oil oxidation, which can lead to sludge and varnish formation.
- Dispersants: Keep contaminants like carbon, soot, and microscopic metal particles suspended in the oil, preventing sludge formation.
The precise blend of base oils and additives determines an oil’s performance in different engines and operating conditions. High-quality formulations provide superior protection, reduce maintenance costs, and extend engine life.
Essential Functions of Motor Oil
Motor oil does more than just lubricate an engine—it plays a vital role in ensuring smooth operation and longevity. Its carefully engineered formulation supports multiple functions that keep an engine running efficiently.
Minimize Friction
A thin film of oil coats moving parts, reducing friction and wear between metal surfaces. This prevents excessive heat buildup and mechanical damage, ensuring smoother performance and longer engine life. Advanced formulations with molybdenum disulfide or boron compounds enhance friction reduction, especially in high-stress applications.
Clean
Motor oil plays a crucial role in keeping the engine clean by removing and suspending dirt, carbon deposits, and combustion byproducts. These contaminants can accumulate over time, leading to reduced performance and potential engine damage.
Where Does Dirt Come From?
Dirt and contaminants enter the engine from multiple sources:
- Air Intake: Dust, pollen, and debris from the environment can enter through the air filter, especially if it’s clogged or damaged.
- Combustion Process: Fuel and oil burning inside the engine produce carbon deposits and soot, which can stick to internal components.
- Metal Wear Particles: Over time, engine components naturally wear down, releasing microscopic metal shavings into the oil.
- Residual Oil Breakdown: Old or overheated oil degrades, forming sludge and varnish that stick to engine parts.
Effects of Dirt and Deposits
- Blockages in Oil Passages: Contaminants can clog small oil channels, restricting proper lubrication and leading to increased wear.
- Increased Friction and Heat: Sludge buildup on moving parts reduces lubrication efficiency, causing overheating and potential engine failure.
- Corrosion and Wear: Acids and debris in dirty oil accelerate metal corrosion, shortening engine lifespan.
Cool
By absorbing and dissipating excess heat, motor oil prevents overheating and thermal breakdown. It carries heat away from friction points and transfers it to the oil pan, where it is released. High-performance synthetic oils with ester-based formulations provide superior thermal stability for extreme conditions.
Act as a Dynamic Seal
Oil forms a thin seal between the piston rings and cylinder walls, improving combustion efficiency by preventing fuel and air leakage. Proper sealing ensures maximum power output and reduces emissions. Polymer-based viscosity modifiers help maintain this sealing effect across varying temperatures.
Dampen Shock
During combustion and sudden load changes, engine components experience shock forces that could cause damage. Motor oil cushions these impacts by providing a fluid barrier, reducing stress on bearings and other sensitive parts. Phosphorous-based anti-wear agents enhance this protective function.
Protect Against Corrosion
Corrosion is a serious threat to engine components, reducing efficiency and leading to costly repairs. Motor oil contains anti-corrosion additives that prevent metal surfaces from deteriorating due to exposure to moisture, acids, and oxidation.
Effects of Corrosion on the Engine
- Weakened Metal Components: Corrosion slowly eats away at metal surfaces, weakening parts such as pistons, bearings, and crankshafts, which can lead to mechanical failure.
- Increased Friction and Wear: Rust and corrosion create rough surfaces, reducing lubrication effectiveness and causing excessive friction between moving parts.
- Oil Contamination: Corroded metal particles mix with the oil, forming sludge and abrasive debris that further accelerates engine wear.
- Reduced Fuel Efficiency: Corrosion in fuel injectors or intake valves disrupts airflow and fuel combustion, lowering engine performance and increasing fuel consumption.
- Potential Engine Seizure: Severe corrosion can lead to internal parts sticking together, preventing the engine from running properly or even causing complete failure.
How Motor Oil Prevents Corrosion
Motor oil contains Zinc Dialkyldithiophosphate (ZDDP) and alkylated diphenylamines, which neutralize acids and create a protective barrier on metal surfaces. These additives prevent oxidation and moisture from causing rust, ensuring that the engine remains in top condition even under harsh conditions. Using high-quality oil with strong anti-corrosion properties extends engine life and reduces maintenance costs.
Transfer Energy
In hydraulic systems and certain engine components like variable valve timing (VVT) systems, motor oil serves as a medium for energy transfer. It helps operate mechanisms by transmitting hydraulic pressure, ensuring proper engine function and efficiency.
A high-quality motor oil formulation balances all these functions, offering maximum protection, efficiency, and performance in modern engines.
Viscosity Meaning?
Viscosity refers to a fluid’s resistance to flow. In motor oil, it determines how easily the oil moves through the engine and coats its components. A high-viscosity oil is thicker and flows more slowly, while a low-viscosity oil is thinner and flows more easily.
Is Thinner Oil Always Better?
Not necessarily. While low-viscosity oil flows faster and reaches engine components quickly, it may not always provide sufficient protection. High-viscosity oil, on the other hand, forms a thicker protective film, which is beneficial in high-load or high-temperature conditions.
- Too Thin: If the oil is too thin for the engine’s requirements, it may fail to create a strong enough barrier between moving parts, leading to increased wear and potential damage under high stress.
- Too Thick: If the oil is too thick, it may not circulate quickly enough in cold starts, causing delayed lubrication and increased resistance, which reduces fuel efficiency.
Why Is Viscosity Important?
- Lubrication Efficiency: Proper viscosity ensures that engine parts remain coated with oil, reducing friction and wear.
- Temperature Stability: Oil must flow smoothly at low temperatures while maintaining thickness at high temperatures to provide protection.
- Oil Film Strength: The right viscosity maintains a protective layer between metal surfaces, preventing direct contact and minimizing damage.
The right viscosity allows an engine to perform efficiently, preventing excessive wear and thermal breakdown under different operating conditions.
SAE viscosity grades (oil weights)
SAE (Society of Automotive Engineers) viscosity grades classify motor oil based on its flow characteristics at different temperatures. These grades help determine which oil is best suited for specific engines and operating conditions.
How SAE Viscosity Grades Work
Motor oil is assigned a single-grade or multi-grade rating based on its behavior in cold and hot conditions:
- Single-Grade Oils: These oils, such as SAE 30 or SAE 40, have a fixed viscosity and do not adjust to temperature changes. They are mostly used in older engines or specialized applications.
- Multi-Grade Oils: The most common type, multi-grade oils (e.g., 5W-30, 10W-40) contain viscosity modifiers that allow them to flow well in cold temperatures while maintaining thickness at high temperatures. The “W” stands for winter, indicating the oil’s cold-temperature performance.
Choosing the Right SAE Viscosity Grade
Selecting the correct oil weight or oil grade depends on engine requirements, climate, and driving conditions:
- Cold Climates: Lower viscosity at low temperatures (lower “W” number) helps with easier startups and better lubrication in freezing conditions.
- Hot Climates: Higher viscosity at operating temperatures ensures the oil remains thick enough to protect engine components under extreme heat and heavy loads.
- Manufacturer Specifications: Automakers recommend specific SAE grades for each engine to provide the best balance of fuel efficiency, protection, and performance. We recommend you put the oil recommended in owner’s manual
Oil Classification
Motor oils are classified based on performance standards, composition, and application, ensuring they meet the needs of different engines and operating conditions. These classifications are established by organizations such as the API (American Petroleum Institute), ACEA (European Automobile Manufacturers’ Association), and ILSAC (International Lubricants Standardization and Approval Committee).
API Classification
The API classification system categorizes oil into two main type of oil:
- S-Series (Service Category) – Designed for gasoline engines. Examples include API SP, SN, and SM, where each newer category offers better protection against wear, deposits, and sludge formation.
- C-Series (Commercial Category) – Developed for diesel engines. Examples include API CK-4, CJ-4, and CI-4, which focus on handling higher loads, soot control, and thermal stability.
ACEA Classification
The ACEA system is widely used in Europe and includes categories for different engine types:
- A/B Series: Covers gasoline (A) and light-duty diesel (B) engines, such as ACEA A3/B4, known for high-performance protection.
- C Series: Designed for modern engines with emission control systems, such as ACEA C3, which offers low-SAPS (Sulfated Ash, Phosphorus, and Sulfur) formulations.
- E Series: Used for heavy-duty diesel engines in commercial vehicles, such as ACEA E9, which provides extended drain intervals and high-temperature stability.
ILSAC Classification
ILSAC works closely with API to develop fuel-efficient motor oils for modern gasoline engines. Common categories include:
- GF-6A: Improves fuel economy while providing protection against wear and deposits.
- GF-6B: Designed for low-viscosity oils (e.g., 0W-16) to enhance fuel efficiency without sacrificing protection.
Why Oil Classification Matters
Choosing the right classification ensures the oil meets engine requirements, enhances performance, and extends engine life. Always refer to the manufacturer’s recommendations to select the best oil for a specific car.
The right motor oil is essential for maintaining engine health and performance. Understanding oil grades, API classifications, and oil change intervals helps ensure your car runs smoothly in all conditions.
Example of Engine Oil to Analyze Type
As you can see in the following image, we have a plastic can of Engine oil. Now let’s explain its properties based on the spec found on the label.
- Fully Synthetic: Made from fully synthetic base oils Group IV
- API: SP Following the latest standards specified by American Petroleum Institute in May 2020. Suitable for any vehicle type manufactured after 2020 (you can use this oil also for older models, but older APIs are more affordable.)
- 0W40: High number indicates it is best for your car in hot weather.
- 100% Virgin Base Oil: Made only from high quality premium virgin oil. Recycled oils are not used to manufacture this motor oil
Using the best performance engine oil extends the life of your car, improves fuel efficiency, and prevents costly repairs. Whether you need full synthetic, conventional, or high-mileage oil, selecting the correct oil grade ensures better performance and engine longevity.
Essential Points
This motor oil guide has covered the basics for beginners. Selecting the right motor oil doesn’t have to be confusing. Understanding the difference between synthetic and conventional oils and about oil grades is crucial for your engine to run smoothly and efficiently for years to come. This motor oil guide serves as a foundation for continued learning, and as you gain knowledge, will save you money and prevent potential engine problems.