Are you trying to figure out what SAE stands for in motor oil?

A lot of car owners know what specific engine oil his/her car requires. This is also mentioned in the car’s owner manual. However, not many people know why engine oil starts with the letters “SAE”.

In this article, you will learn about the meaning and a lot more about SAE motor oil.

SAE Motor Oil Meaning

SAE stands for “Society of Automotive Engineering”. They came up with a brilliant code system to grade motor oils according to their viscosity. Viscosity is measured by how long it takes a certain amount of oil to flow through a container at a specific temperature. If a liquid has high viscosity, it means it will take a longer time to flow whereas liquids with low viscosity flows faster.

Overfilling Engine Oil

The motor oil grade is usually written as follows “XW-XX”. For example: SAE 10W-30, SAE 10W-40 or SAE 30. We already know what SAE stands for. Now let’s try to understand the other characters. “W” refers to ‘winter’ and not weight as many people think. The number mentioned before W indicates the oil flow at 0 degrees Fahrenheit (-17.8 degree Celsius), which means that the lower that number, the less the oil will thicken in cold conditions. In countries where the climate is usually cold, a motor oil with 0W or 5W viscosity would be ideal.

The number mentioned after “W-XX” indicates the oil viscosity measured at 212 degrees (100 degrees Celsius). It represents how quickly the oil will thin out at a higher temperature. For example, the 10W-30 oil with thin out more quickly at a higher temperature compared to the 10W-40 oil.

Single-Grade Vs Multi-Grade Oil

Single-grade engine oils cannot use viscosity modifier additive and have 11 established viscosity grades out of which six are denoted with the letter “W”. These 11 grades are 0W, 5W, 10W, 20W, 20, 30, 40, 50 and 60. Single-grade engine oils are also called ‘straight-weight’ oils.

Multi-grade oils support a large temperature range in which they can remain exposed and not deteriorate. Since a certain engine oil will have high viscosity when the engine is cold and a lower viscosity when the engine is operating at its normal temperature, this difference has to be taken care of and is done through a special polymer additive called “viscosity index improver”. These additives ensure that one type of oil can be used throughout the year even when the climate changes.

Single-grade oils are no longer used in the latest automobile engines due to the large difference between their viscosities in extremely low or extremely high temperatures. However, antique or vintage cars might still function properly with single-grade oil. Moreover, single-grade oil is usually recommended for lawn mowers, garden tractors and generators etc.

Types of Motor Oils

There are many different types of motor oils available on the market and it is a good idea to be educated about them in order to help you make the right decision the next time you go for the oil change.

Conventional Oil

Conventional oil is the cheapest and is available in bulk at auto stores. It follows the API and SAE standards but is not rich in additives. If you change your car’s engine oil too frequently, then this type of oil is not a bad option.

Premium Conventional Oil

This oil is more commonly used and is recommended by car manufacturers. The widely used grades are 5W-20, 5W-30 or 10W-30 and they are perfect for most of the light-duty vehicles.

Full-Synthetic Oil

Full-synthetic oil is specially made for high-tech engines which demand superior performance and flawless lubrication. These oils pass through specialized tests and provide a high viscosity level, prevent oxidation and resist thermal breakdowns. This type of oil also improves fuel efficiency and offers better horsepower. Naturally, they are expensive but also long-lasting.

Synthetic Blend Oil

This is the preferred oil type for pickup trucks and SUVs as it offers increased protection for heavy-duty engines. Synthetic blend oil is essentially a premium conventional oil mixed with synthetic oil.

High-Mileage Oil

A lot of people have cars with more than 75,000 miles on the odometer and to protect and ensure the longevity of their engines, high-mileage oil was developed. Seal conditioners are added to the oil and they have proven to be effective for some engines.

Drawbacks of Adding Viscosity Improving Additives

Although adding additives improves the viscosity, they are also known to cause sludging and also deplete at higher temperatures, making the motor oil thinner. This is the reason why many auto manufacturers are now developing motor oils without additives. If you are looking for an oil additive for your engine, you can check out this additive with others on Amazon: Liqui Moly 2009 Anti-Friction Oil Treatment Link to Amazon. The most common types of additives found in motor oil are:

  • Detergents: Help in removing deposits
  • Antiwear additives: Protect cylinder walls, lifters, cams and piston rings etc.
  • Dispersants: Absorb solid contaminants so they don’t damage the engine
  • Friction modifiers: Reduce friction
  • Viscosity-index improvers: Prevent oil from thinning

Choosing the right motor oil for your car engine is essential as it ensures the long life of your engine and also improves the performance of the vehicle. For new vehicles, you can easily check the recommended engine oil from the owner’s manual whereas for old models, just ask an auto-repair specialist.


  • SAE stands for “Society of Automotive Engineering”
  • SAE is the denote of the viscosity of the engine oil
  • The W stands for winter

If you have any other questions about engine oil or have any additional information that you want to share, please comment below. If you have any other car questions, you can ask them at our homepage and we will help you as soon as possible.