What Do the Numbers on Motor Oil Mean?

The average layperson might think that all motor oil is the same. No one really thinks about the different levels of oil thickness or how much of an influence hot and cold temperatures have on the oil. If you regularly take your vehicle to an auto servicing shop for its oil changes, then you’ll never need to concern yourself with the type of oil you’re using. The auto technician usually knows the right oil to use, and they’ll do the thinking for you.

Of course, you can save a lot of money by doing your own oil changes. You just need to understand how to tell the different oil types apart from each other. The best way to do that is by looking at the numbers on the label. Every oil container has a series of numbers on it with the letter “W” in the middle of them. Some examples of this include 10W30, 5W20, 5W30, 10W40, etc. It almost looks like some secret code that only a trained auto technician would know.

The numbers on motor oil are not codes, though. They are actually measurements of viscosity, which refers to the thickness level of the oil fluid. The “W” in the middle of each number set refers to “Winter.” On the left side of the “W,” that number references the viscosity of oil under colder temperatures. On the right side of the “W,” that number references the viscosity of oil under hotter temperatures.

Read also:

The lower the first number is, the thinner the oil is. Cold temperatures harden oil and make it thicker. Therefore, you’ll want to have thinner oil if you’re in a colder environment because the thin oil won’t turn too thick. On the other hand, if the first number of the oil is higher, then it means you have thicker oil. You certainly don’t want to put thick oil in your engine if you’re in a cold environment because the oil will turn even thicker. On that happens, the oil circulation in the engine will be very poor. This will ultimately limit the performance of your engine.

As for the second number which comes after the “W,” this refers to the thickness level of oil in hotter temperatures. Aside from the hot temperatures of the outside environment, this also factors in the hot temperatures of the engine as well. Basically, the second number should be higher if you want thicker oil. When dealing with hotter temperatures, thicker oil is better because heat thins out the oil just enough for it to flow properly in the engine. If you put thin oil in an engine and then expose it to heat, the oil will become too thin. Then it won’t be able to lubricate the engine properly.

Choosing the Right Oil

The average American will either put 5W30 or 10W30 in their engine because the temperatures tend to be both warm and cold throughout the year. However, a frequently cold location like Russia would require thinner oil regularly, such as 0W30 or 0W20. But if you’re living in an extremely hot location like Egypt, then you would want thicker oil in your engine, such as 15W40, 10W40, or 20W50.

If you’re still confused by all this, ask an auto professional what they think you should use. Don’t believe the motor oil recommendation of your car manufacturer because they don’t factor in the temperature of your surroundings. Some people travel to different locations, which might require frequent oil changes with new types of oil. The environment means everything when choosing the best motor oil for your car.

Add a Comment

Your email address will not be published. Required fields are marked *