How to choose the right engine oil?

With so many motor oil options available, selecting the right oil for your car may appear to be a daunting task. While there is a wealth of information available about the various oil options, the first step is actually quite simple: Examine the owner’s manual for your vehicle.

The recommended oil weight for your vehicle will be listed in the owner’s manual, whether it’s a standard format like 10W-30 or something more unusual. That figure represents the viscosity (or thickness) of the oil you should use. As mentioned below, you should change the weight and kind of the car based on the season and how you want to use it. What is listed in your owner’s manual is sufficient for regular use in moderate temperatures. Always buy oil from a brand that has the starburst symbol, which indicates that the oil has been tested by the American Petroleum Institute (API).

On the container, you’ll also notice a two-character service designation. The most recent API service standards are SP for gasoline engines and CK-4 for diesel engines. These letters are based on a series of laboratory and engine tests that determine the oil’s ability to protect the engine from wear, high-temperature deposits and sludge, and other contaminants. If you’re interested, the API has a complete list of these standards here, but make sure you’re buying oil that has been tested to the most recent standard. As of this writing, these are SP, SN, SM, SL, and SJ for gasoline engines, and CK-4, CJ-4, CI-4, CH-4, and FA-4 for diesels.

That’s the gist of the narrative, but there’s a lot more to it than that.