Understanding the Key Differences Between Motor Oil Types

With the rapid evolution of automotive technology, the performance demands placed on engine lubricants have significantly increased. As a result, motor oils have evolved to meet these new requirements, resulting in a wide range of advanced formulations. Understanding the key differences between motor oil types is essential for ensuring optimal engine protection, efficiency, and longevity. 

Types of motor oils

Motor oils are primarily classified into mineral and synthetic oils. Each category is engineered to suit specific engine requirements and operating conditions.

Mineral Oils (Conventional Oils)

Mineral oils are produced through the refining of crude petroleum. They are generally recommended for older engine models or vehicles with lower performance demands. While they offer fundamental lubrication, their limitations become evident under high-stress conditions, such as elevated temperatures, extended drain intervals, or heavy loads.

Due to their natural composition, mineral oils often fall short in meeting the latest standards for fuel efficiency, emission control, and advanced engine cleanliness.

Synthetic Oils (Semi- and Fully Synthetic)

Synthetic oils are formulated using advanced chemical processes to deliver superior performance across a wide temperature range and in more demanding environments.

Semi-synthetic oils combine mineral base oils with synthetic components, offering enhanced performance over conventional mineral oils while remaining cost-effective.
Fully synthetic oils are engineered for maximum protection, stability, and efficiency, making them ideal for high-performance and modern engines.

There are two common synthetic oil production methods:

  • PAO (Polyalphaolefin)-based synthetics: These oils provide excellent thermal stability and flow properties, especially in extreme conditions. However, due to their high production costs and evolving standards, their use is becoming more limited.
  • Hydrocracked (HC) or Group III+ synthetics: These oils are now the industry benchmark, delivering high purity and exceptional performance. They comply with stringent API, ACEA, and OEM standards, and are widely used in modern lubricant formulations.

Note: The classification of oils as “synthetic” or “mineral” can differ depending on regional standards and definitions.

Understanding viscosity in motor oils

Viscosity is a critical property that defines how easily oil flows at different temperatures. It is expressed in a two-part code, such as 5W-30:

  • The second number reflects the oil’s viscosity at engine operating temperatures (typically 100°C).
  • The “W” stands for “winter” and indicates the oil’s cold-start performance.
Example:
  • A 5W-40 oil offers better low-temperature performance than a 10W-40.
  • A 10W-30 flows more easily at operating temperature than a 10W-40.

While viscosity influences oil flow and fuel efficiency, it is not a direct measure of oil quality. The formulation’s effectiveness depends largely on its additive package.

Why are motor oils becoming thinner?

Modern engines are engineered with tighter tolerances, sophisticated emission control systems, and turbochargers designed to achieve greater fuel efficiency. As a result, manufacturers now prefer thinner oils to reduce internal friction and support cleaner combustion, thereby lowering fuel consumption and emissions.

Benefits Include:
  • Fuel Savings: Less parasitic drag on moving parts
  • Reduced Emissions: More consistent oil flow supports cleaner combustion
  • Improved Cold-Start Protection: Faster oil circulation upon start-up
  • Industry Standards: Recent specifications like API SQ (an early low-viscosity category, later replaced by SN/SP), ILSAC GF-6B for backward-compatible 0W-16 grades, and the forthcoming ILSAC GF-7, focus on enhanced fuel economy and engine protection.

API SQ was introduced to certify oils optimized for thin viscosities and improved fuel economy but was superseded by API SN and SP categories. ILSAC GF-6B standards address modern turbocharged engines and tighter tolerances, enabling ultra-low viscosities while ensuring shear stability. ILSAC GF-7, expected in 2025, will further raise the bar on fuel efficiency metrics and compatibility with hybrid powertrains.

As viscosity decreases, the role of additives becomes increasingly vital. Additives are specifically blended to:

  • Enhance lubrication and reduce wear
  • Maintain internal engine cleanliness
  • Protect against oxidation and corrosion
  • Regulate heat and extend oil life

Today, additives can account for up to 30% of the oil formulation, with the base oil acting primarily as a carrier for these performance enhancers.

Selecting the right motor oil for your vehicle

Choosing the correct motor oil is essential for preserving engine health and performance. With numerous OEM specifications in circulation, selecting an oil that meets your engine’s specific requirements is crucial.

To ensure proper oil selection:

  • Always consult your vehicle owner’s manual
  • Verify that the oil meets the recommended performance specifications and viscosity grade

To make this process easier, Lubrex offers a user-friendly Oil Finder Tool. Simply input your vehicle details to find the most suitable motor oil in seconds.

For more information about our full range of lubricants and technical guidance, visit www.lubrex.net 

Lubrex’s product portfolio

Our company, Lubrex, takes pride in delivering a complete range of top-tier motor oils tailored to every engine type and operating need. We offer two distinct series:

  • PCMO Series (Velocity™): Tailored for passenger cars and light-duty applications. These mineral, semi-synthetic, and fully synthetic formulations carry broad OEM approvals (Volkswagen, Mercedes-Benz, etc.) and meet industry standards such as API, ACEA, and ILSAC.
  • HDDEO Series (Momenta™): Built for heavy-duty diesel engines under extreme loads and high temperatures. Our Momenta™ blends and synthetics feature OEM endorsements from Volvo, and Mercedes-Benz, while conforming to API and ACEA industry standards.