What do the numbers on engine oil mean?
Most people have changed their car’s oil themselves or taken their car to a quick lube shop, auto repair shop, or dealership and had professionals do it for them. An important aspect of oil changes is choosing the correct type of oil.
It does not directly mean choosing between synthetic or conventional base oil. You should also pay attention to the numbers on the engine oil label. You may see something like “10W-30” or “5W-20” and wonder what that means.
Even if you have had your oil changed by a professional, they usually put a sticker on the windshield that shows how much oil they used in your vehicle. What do these numbers mean?
In short, the numbers before and after the W indicate viscosity. The letter “W” itself represents winter. As you know, viscosity means the thickness of a fluid. In the case of motor oil, it is the thickness of the oil under certain temperature conditions.
Related: Signs of Using the Wrong Motor Oil
Oil Viscosity
the first number
The number to the left of the W refers to the low-temperature viscosity of the oil. The number to the right of the W refers to the viscosity of the oil at higher temperatures.
If the first number is low, it means you have thin oil. Whenever temperatures are colder around you, it is better to have thinner oil in your engine. Otherwise, it will be more difficult for the thicker oil to flow through your engine and lubricate its components.
the second number
The second number will depend on two things: the temperature of your engine and the heat of your surroundings. If you live in a tropical area with a lot of heat, you’ll want this high second number because it means the oil is thick. A thick oil is good at high temperatures because it will do a better job of lubricating the engine components.
In the United States, there are two commonly used motor oils: 10W-30 and 10W-40. If you live in an area with very cold winters, like Michigan or most of Canada, you may need a thinner oil, like 0W-30. Also, if you live in a very hot climate like Arizona, you can use 10W-40, 20W-50, or 15W-40.
If you check your vehicle’s owner’s manual, it will tell you the proper viscosity grade of oil to use in your vehicle. However, the manufacturer does not always take into account where in the world he lives or where he can move his vehicle as well.
Therefore, you need to understand the different types of motor oils so you can form your own opinion.
