The Different Motor Oil Standards Explained

Author: Emily Scott

If you care about your car, then you need to care about its engine too. This is because the engine is the lifeblood of your car that keeps it running and on the road. When it comes to engine care, the first and probably the most important step is using the right engine oil for your car. However, with so many motor oil options out there, ensuring this can be a daunting task.

One thing that you can do to make this task easier is to look for only high-quality synthetic engine oil. Are you wondering what makes a high-quality engine oil? It’s an engine oil that meets the required quality standards. One example would be the Motul synthetic engine oil. So, what are the quality standards that you need to look for when choosing an engine oil for your car? We will be discussing that next.

The SAE Oil Standard

Today, many car owners are transitioning from a 5W-30 engine oil to a 10W-30 engine oil. This is a standard that shows the viscosity of the engine oil. It is determined by the Society of Automotive Engineers (SAE). In the U.S, it is referred to as the ‘weight’ of the engine oil. It is important to note that the first number and the last number of the standard indicate two different things.

For instance, in the 10W-30 engine oil, the number ‘10’ indicates the ease with which the oil pours at low temperatures or when the engine starts. This number is most relevant during the colder months when many car engines have trouble starting. The ease or speed with which the oil will pour during the colder months will increase as the number lowers from 10 to 9 and so forth.

The number ‘9’ is mentioned just for understanding purposes, and the standard lower than the 10Wengine oil is the 5W motor oil. There are eleven viscosity grades in total, starting at OW and ending at 60W.

The other number shown on the 10W-30 engine oil standard, which is ’30,’ indicates the ease with which the oil flows in hot weather or at operating temperatures. The ease or speed with which the oil will flow during the hotter months will increase as the number increases from 30 to 40 and so forth. The higher the number, the more likely the motor oil is to protect your engine components in hot and extreme conditions.

The API Oil Standard

If you’re not sure about which grade is best suited for your car, then you should look up the manual which came with your car as the recommended oil weight will be listed in it. Not only do you need to pick the right oil standard, but you also need to make sure that engine oil you choose features the American Petroleum Institute (API) ‘Donut’ or service symbol. This is important because the API donut shows that API has tested the oil for quality. The API donut is evident on a high-quality engine oil such as the Motul synthetic engine oil.

Two different letters indicate the API standard for diesel and gasoline engines. C is for diesel engines, while S is for gasoline engines. The letter ‘S’ or ‘C’ is followed by another letter, which indicates the performance of the oil. The quality of the oil increases as we move further along the English alphabetic system. For example, an SM oil will have a higher performance than an SN oil; an SL oil will have a higher performance than SM oil, and so on.

The ACEA Oil Standard

If you happen to own a car manufactured in Europe, then you may want to get familiar with the ACEA oil Standard. ACEA refers to the European Automobile Manufacturers' Association, and they have set the standards for the motor oil to be used in the different types of vehicles. The vehicles are separated into four different categories, and the oil standard for each category is indicated by a different letter, as shown below:

  • A—for petrol engines
  • B—for diesel engines in private cars
  • C—for light engines featuring particulate filters or catalytic converters
  • E—for trucks and other vehicles used for commercial purposes

The above letters are followed by a number which indicates the performance level of oil. The higher the number, the better the performance of the oil. For example, an A2 standard oil is likely to perform better than an A1 standard oil; A3 will perform better than A2 and so on. The oil standard for petrol engines starts at A1 and goes up to A5; the same is true for both diesel engines and engines equipped with a device to control pollution. However, the oil for commercial vehicles and trucks has only four categories, which are E4, E6, E7, E9.

Final Word

While picking the right engine oil for your vehicle can be difficult, you can at least ensure the quality of the engine oil you choose by looking for the motor oil standards explained above. This will keep your car’s engine healthy and useful for longer.