Do combinations of letters and numbers on motor oil bottles everywhere confuse you? Here you can learn how to decipher what they mean. But to do that, you should know about viscosity.

In plain and simple words, Viscosity measures how much motor oil can resist flow. Meaning, if you tip a motor oil bottle over, how fast it spills out indicates its viscosity. The more viscous, the slower it moves.

To specify viscosity, the Society of Automotive Engineers (SAE) has developed a standard scale.

0W is thinnest (“W” stands for winter). Then there’s 5W, 10W, 15W, 20W, 25W and 20, 30, 40, 50, 60 being the thickest. Why winter, you shall know soon.

Now, coming back to 10W30, will mean the viscosity is at 10W when the engine is cold and 30 when the engine is hot.

10W30 is the perfect choice for your vehicle for using in warmer weather if you have heavy load and commercial vehicles. Also, its greater sealing capability makes this your best bet if you have an older engine

What good do low viscosities do?

Low viscosities are good for cold temperatures (hence the “W” association) because the oil is thinner. Thinner motor oil flows more easily inside the engine. When you start a cold engine up again, motor oil first travels back to the top of the engine, from where it trickles back down. Since motor oil is vital to lubricating your engine, it needs to move quickly and low viscosity helps it do just that.

To find out which motor oil grade is right for your vehicle, refer to your vehicle’s owner’s manual.

What happens when engine heats up?

When your vehicle’s engine heats up, higher viscosities will mean that the motor oil would not thin out and will keep parts separated by a film of oil. Interestingly, a motor oil is always maintaining a delicate balance in the engine. It needs to flow well when the engine is cold but also retain enough body at higher temperatures to keep metal parts lubricated and separated.

Is 5w30 better than 10×30?

The lower viscosity of 5W30 will be ideal for use in cold weather as the oil is thin enough to get into different parts of the engine despite the cold weather conditions. It also ensures easy engine startups. The thinner nature of this oil, as compared to 10×30 will warrant your vehicle maintains optimal performance in winter.

Also, 5W30 is more ideal for use on the light-duty diesel or petrol vehicles. This is because its lower viscosity means it will not require a lot of power to move it around the engine.

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