Multigrade engine oils are engine oils designed to provide effective lubrication and protection at both high and low temperatures.

This term refers to oils that meet the requirements of several viscosity grades, combining a “W” grade for winter or low temperature performance and a single grade for normal operating conditions.

SAE (Society of Automotive Engineers) viscosity grades, such as SAE 10, SAE 30, SAE 40 and SAE 50, are used to classify engine oils according to their thickness or viscosity at different temperatures.

It is important to note that these viscosity grades represent a single viscosity at operating temperature, unlike multigrade engine oils (e.g., 10W-30 or 5W-40), which offer different viscosities depending on temperature.

How Multigrade Engine Oils Work

Here is an exploration of what multigrade means in the context of engine oils:

Performance over a wide temperature range

Multigrade engine oils are formulated with special additives and base oils that enable them to maintain a constant viscosity over a wide temperature range. They offer improved fluidity characteristics on cold starts, ensuring adequate lubrication even in low temperature conditions.

Benefits of Multigrade Motor Oils

The “W” in the viscosity grade (e.g. 5W-30) indicates its performance in winter or at low temperatures.

Cold start protection

In cold weather, engine oil tends to thicken, which can hinder its ability to flow quickly and provide adequate lubrication during initial engine start-up.

Multi-grade engine oils with lower “W” viscosity grades, such as 0W, 5W or 10W, have better flow properties at low temperatures, allowing them to reach critical engine components more quickly and reduce wear during cold starts.

High-temperature stability

Multigrade engine oils are also designed to maintain their viscosity and stability at higher temperatures. When the engine reaches operating temperature, the oil must have sufficient thickness or viscosity to provide adequate lubrication and prevent metal-to-metal contact.

The monograde viscosity index in a multigrade oil ensures its suitability for normal engine operating conditions.

Engine protection and longevity

The ability of multigrade engine oils to operate effectively at different temperatures helps protect the engine against wear, corrosion and deposits. Proper lubrication helps reduce friction and heat generation, promoting engine longevity and overall performance.

How do Multigrade Motor Oils work

Fuel Efficiency

Multigrade engine oils can also contribute to improved fuel efficiency. Lower viscosity grades W reduce drag caused by thickened oil during cold starts, while higher operating temperature viscosity helps maintain adequate lubrication without excessive energy loss due to internal friction.

By combining different viscosity grades in a single oil, multigrade engine oils offer the advantage of adapting to various temperature conditions, providing optimum lubrication and protection for engines in both cold and hot climates.

Where to buy your multigrade engine oils

At American Petroleum we have a wide variety of motor oils, including the private line of American Quality Lubricants, which includes multigrade and regular oils. In the list of products we have shared with you above you can see the specific names.

Feel free to contact us to find out how to place your order.


Multigrade Oil – To Use or Not to Use. Machinery Lubrication. Accessed January 30, 2024.

What Is Multigrade Oil? (Definition, Benefits, FAQs). AutoNation Mobile Service. Accessed January 30, 2024.

WHAT IS MULTI-GRADE OIL? TDX. Accessed January 30, 2024.

Multi Grade Car Engine Oils Explained. Opie Oils. Accessed January 30, 2024.