WHAT IS 0W-20 MOTOR OIL?

Changing needs of vehicles for motor oil grades

Over the years, the most popular and commonly used motor oil grades have changed to keep up with changing engines of the auto manufacturers.  In the 1960’s, it was common for a vehicle to require a monograde oil and the viscosity or grade of the oil required would change depending on the season.  As motor oil chemistry advanced, multi-grade oils replaced the need to change grades based on seasons or weather.

As vehicle engines technology has improved with time, the size and power output of engines have significantly changed.  In the 1970’s, it was common to have a very large engine (6-cylinder and 8-cylinder engines were the most common) that had large pathways for oil to travel through to protect the engine.  At that time, 20W-50 and 10W-40 were the most popular grades.  When fuel economy increased in importance, engine sizes got smaller and lower viscosity motor oils were needed – this led to the rise in popularity of the 10W-30, 5W-30 and 5W-20 grades over the years. 

Today, engines are advancing faster than ever.  Auto manufacturers are looking to make engines smaller and lighter while delivering more power than ever.  To protect these smaller powerful engines, thinner oils with better ability to protect and clean engines are needed.  This has led to 0W-20 being the fastest growing grade in the motor oil marketplace.

0W-20 – What does it mean?

Looking at the number 0W-20 (and motor oil grades in general) can be confusing.  Why is there a zero in the grade?  Does that mean I have less protection?  To get a better understanding, let’s discuss the motor oil grading system.

Motor oil grades are defined from an industry specification known as SAE J300 (SAE = Society of Automotive Engineers).  Oil flows differently at lower temperatures than higher temperatures.  Picture starting a car on a cold winter morning versus driving on a desert highway in the summer.  The flow of oil in the engine is very different in those two situations.  The flow and its resistance to movement of a fluid is known as the viscosity of the fluid and is very important in motor oil.

Motor oil viscosity is commonly measured at lower and higher temperatures.  The properties of the oil at lower temperatures define the first part of the motor oil grade.  In the example of a 0W-20, the “0W” part of the grade is related to the measurement of viscosity at low temperatures as defined by SAE J300 (and the “W” stands for Winter – relating it to low temperature performance).  The better the oil performs at lower temperatures, the lower the number before the W.  The numbers are ranges defined by SAE J300, so zero doesn’t mean zero performance; it means the oil performs better at lower temperatures and flows easier than oils that fall in 5W, 10W, 20W, etc. ranges.

The “20” portion of the 0W-20 grade relates to how the oil flows through the engine at higher temperatures – like when your engine gets up to normal operating temperatures.  As a reference, think of it as how your oil flows when your engine has warmed up and you are driving on a highway.  Again, the lower the number, the thinner the oil is and easier it flows around your engine.  An oil that has a 20 after the W flows easier and faster than an oil with a grade that ends in 30, 40, 50, etc.

What type of oil is a 0W-20? 

To make a 0W-20, high quality base oils and strong additives are needed.  The base oils must be able to protect and flow at very low temperatures.  Typically, a large amount of synthetic oil is needed to allow the oil to flow well at these low temperatures.  0W-20 motor oils require synthetic base oils and are either full synthetic or part synthetic (synthetic blend) motor oil; 0W-20 oils are not conventional (or mineral) motor oils.  And the additives must be thin enough to move well but still protect these newer advanced engines.

Why is 0W-20 becoming such a popular grade?

Currently, 5W-30 and 5W-20 are the most popular grades in the motor oil market.  But in recent years, 0W-20 is the fastest growing grade and is in position to be the most common grade recommended by auto manufacturers in the coming years.  The reason for this is due to the technical advancements of automobile engines.  Recent years have seen developments such as hybrid vehicles, cylinder deactivation, stop-start engines, direct injection (GDI) and turbochargers.  All these changes are putting different stresses on the engine and as a result, on the motor oil.  

Despite all this new technology, fuel economy is very important to auto manufacturers.  Auto manufacturers are driving more power out of the same or smaller engines.  This results in the need for a thinner motor oil that are required for these vehicles.  In general, auto manufacturers are requiring a 0W-20 more commonly for their newer vehicles which is the reason for the growth of the 0W-20 in the motor oil market.