The Science of Multi-Grade Oil – The Perfect Solution from AMSOIL

1. What is multi-grade oil?

Multi-grade oil is a type of engine oil that can maintain stable viscosity under various temperature conditions. Before the advent of this oil, users were required to change oil seasonally: thinner oil for winter and thicker oil for summer. However, with advancements in lubrication technology, multi-grade oil allows the engine to operate smoothly all year round without the need for seasonal oil changes.

2. Why is multi-grade oil an essential solution?

Engines operate based on the principle of lubrication to reduce friction and protect important components from wear. However, environmental temperature greatly affects oil viscosity:

• In freezing winter: Oil becomes thicker, slowing down the oil pumping process, making the engine difficult to start and more prone to wear.
• In hot summer: Oil becomes thinner, reducing its ability to form a lubricating oil film, leading to direct metal-to-metal contact and rapid engine damage.

Multi-grade oil addresses both of these issues by combining the properties of low and high viscosity oils, helping to maintain viscosity stability in all weather conditions.

Reference article:

• The truths and insights that experts know about AMSOIL, oil that extends oil change intervals
• Superior cold start engine protection with Amsoil oil

3. Viscosity index of multi-grade oil

To select the right oil, a clear understanding of viscosity indexes is necessary:

The letter "W" in oil: This symbol stands for "Winter" and indicates the oil's flow ability at low temperatures according to SAE J300 standards.
The number following "W": Represents the viscosity of the oil when the engine operates at a standard temperature of 100°C.

For example, multi-grade oil 5 W-30 has low viscosity in cold temperatures (allowing the engine to start easily) and maintains appropriate viscosity when temperatures rise.

4. Benefits of multi-grade oil

Before the existence of multi-grade oil, users had to change oil seasonally to ensure proper viscosity. However, with advanced technology, multi-grade oil offers numerous outstanding benefits:

• Better engine protection: Maintaining stable viscosity helps reduce friction and effectively resist wear.
• Cost savings: No need for seasonal oil changes, reducing maintenance costs.
• Smooth operation: The engine starts easily in cold conditions and operates stably in hot weather.

5. Technology behind multi-grade oil formulation

Multi-grade oil is formulated from premium base oils and special additives, with viscosity modifiers playing a crucial role:

• At low temperatures: Polymers contract, allowing the oil to maintain the necessary liquidity for easy pumping.
• At high temperatures: Polymers expand, enabling the oil to retain adequate