The Different Weights in Motor Oil | Decoding Motor Oil Viscosity

If you are looking at motor oils for your truck, SUV, or Jeep, you probably have seen a lot of numbers and letters.  Unfortunately, motor oil can be confusing for consumers to buy.  And finding the right motor oil for your vehicle’s engine is very important.  Here are some tips on choosing the right motor oil.

The Different Weights in Motor Oil

Two Numbers that Different Weights in Motor Oil

The weight of motor oils means the viscosity of the oil and based on the viscosity, there are two types of motor oil can be found. These classifications of the oil is indicated by providing different letters and numbers. When you shop for motor oil, you will see plenty of numbers and letters.  For instance, you will usually see a motor oil with SAE, W, and S or C.

Here we have discussed the two different motor oils according to their viscosity or weights.

Single-grade Motor Oil

Whenever you will find an oil that is designated by a single number then the oil is a single-grade motor oil. The viscosity of this type of motor oil can be changed at different temperatures. Simply put, it has a fixed viscosity at a specific temperature. The viscosity of this oil is determined by measuring the flow of the oil at a certain temperature.

SAE stands for the Society of Automotive Engineers and this organization has come up with a scale of how to categorize the different motor oils around.

Multi-grade Motor Oil

If you check out modern vehicles, you will find out that there are multi-grade motor oils are used. Now, how to identify that the oil is a multi-grade motor oil. You might see the letter “W” next to a number such as 10W, 5W, 40W, etc. And whenever you find W is written that means the oil is a Multi-grade motor oil.

W stands for winter temperature.  This is usually the coldest temperature that your oil should operate in.  For instance, if you live in a cold environment, you want motor oil with a low-temperature viscosity.  Viscosity is defined as how thin and easy to flow something is.  For instance, water flows pretty easily, but jelly does not.  So for instance oil with 5W means that the viscosity is made for engines operating in 5 degree Celsius winter weather.  On the other hand, if it is the middle of the summer and you live in Texas, you want an oil that is more durable to the heat.  You may want to purchase 40W for your car.

Besides single-grade motor oil, some motor oil can be multi-grade made for a variety of temperatures such as 10W-30W.  This is done with special chemical additives.

Bonus Point: S or C Graded Oil

When you see the letter S, this means spark ignition vehicles- generally for passenger vehicles.  The C stands for commercial vehicles.


Lastly, understanding the different weights in motor oil is very important. By this, you can identify when and where you will need to use the specific motor oil in your vehicle. By doing so, you will get smooth performance from your vehicle and you can maintain the engine properly.

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