How To Choose The Right Motor Oil

Finding The Right Motor Oil

What motor oil is right for my vehicle?
Walking down the motor oil aisle at your local auto supply store can leave you scratching your head. What do all these numbers and letters mean on the various types of motor oil? Why so many types of the (seemingly) same type of motor oil? Well, you don’t have to go back to high school chemistry or junior high algebra to make the right choice. It is always recommended that you chose your motor oil based on your vehicle’s manufacturer requirements – find these in your owner’s manual. Don’t have an owner’s manual? Google it!
However, if you’re just curious about the motor oil grades, we’ve got a little insight for you. Society of Automotive Engineers (SAE) grades motor oil by viscosity, sometimes referred to as an oil’s “weight.” Motor oil viscosity refers to the “flow” of the oil. The quicker and oil flows, the lower its viscosity and grade.

How Does SEA Measure Oil Flow?
As you are aware, oil doesn’t flow at the same rate at all temperatures. SAE uses a baseline of 100 degrees Celsius for most common engine operating temperature. Each grade of oil represents a specific flow at this operational temperature. For example, SAE 30 means that the oil has a viscosity between 9.3 cSt and 12.5 cSt at operational temperature of 100 degrees Celsius.

What is a Multigrade Oil?
Some climates are much colder than others. That’s why it is important that your engines oil can be pumped at lower environmental temperatures, too. If an oil doesn’t perform well before the engine has had time to warm, you might experience engine failure.
If you’ve noticed that there are a lot of oils that have a number that is followed by a “W,” that is a multigrade oil. The “W” stands for “winter” and the number that precedes it represents the oil’s viscosity at extremely low temperatures. These oils can be substituted for eachother based on your operating climate. For example, if your vehicle calls for a 10W-30 but you live in an extremely cold climate, you can also use a 5W-30 or 0W-30 grade oil. The lower viscosity oils can also provide better fuel economy because your engine doesn’t need to work harder to pump the oil.

In short, you should always follow the vehicle owner’s manual when selecting the correct oil. If you have questions or you believe a different oil may perform better in your vehicle, please ask your Red Stick Fleet Mechanic about lower viscosity, high-mileage and synthetic oil blends at your next vehicle service.