Understanding engine oil standards
When choosing an engine oil, understanding its standards can help you identify the oil's viscosity, performance specifications and compatibility with your vehicle.
The three main standards you may see on an engine oil label are ACEA, SAE and API. Always check your vehicle manufacturer's recommendations before choosing an engine oil.
The ACEA oil standard
ACEA stands for the European Automobile Manufacturers' Association. ACEA Oil Sequences define performance requirements for engine oils used in different vehicle applications.
ACEA categories use letters and numbers to identify different oil performance requirements and applications. The category required for your vehicle depends on the manufacturer's specifications.
The SAE oil standard
SAE stands for the Society of Automotive Engineers. The SAE classification describes an engine oil's viscosity, or how easily it flows at different temperatures.
For example, in a 5W-30 oil, “5W” refers to the oil's low-temperature viscosity and “30” refers to its viscosity at high operating temperature.
The lower the number before the “W”, the better the oil flows at low temperatures. The number after the “W” indicates the oil's viscosity at high temperature.
What does the “W” mean in 5W-30?
The “W” stands for “Winter”. It indicates the oil's low-temperature viscosity classification.
The API oil standard
API stands for the American Petroleum Institute. The API classification system identifies engine oil performance categories for gasoline and diesel engines.
API categories use letters to identify the type of engine and the applicable performance category. For example, “S” categories are associated with gasoline engines, while “C” categories are associated with diesel engines.
What do the letters mean in API oil classifications?
The first letter indicates the engine type. The second letter identifies the applicable performance category. Always check your vehicle manufacturer's recommended API specification before choosing an oil.
ACEA vs. SAE vs. API: What's the difference?
| Standard | What does it describe? |
|---|---|
| ACEA | Oil performance requirements and applications |
| SAE | Oil viscosity |
| API | Oil performance categories for gasoline and diesel engines |
These standards describe different characteristics of engine oil. They should not be used interchangeably when selecting an oil. Always follow the specifications recommended by your vehicle manufacturer.
How do I know which engine oil standard my car needs?
The correct engine oil depends on your vehicle manufacturer's specifications. Check your owner's manual to find the required viscosity and performance specifications, such as SAE, API or ACEA.
You can also use LubConsult to find the recommended lubricant for your vehicle.
Frequently asked questions
What does 5W-30 mean?
Designations like 5W-30 or 10W-40 are encountered when choosing an engine oil, but what do they mean?
How do you check and change your engine oil?
Follow these steps to successfully check the oil level of your car.
What is engine oil made of?
Let’s take a closer look at what goes into this essential lubricant, and the role of the main additives used.
