How to Compare Automobile Oil
- 1). Know the oil's function. Every single bottle of engine oil you see on the shelves of supermarkets and auto parts stores has the main purpose of decreasing friction between moving parts, transferring heat away from the engine and cleaning the engine from waste particles like metal, dirt and plastic.
- 2). Look at the oil weight number on the container. Oil weight is also known as oil viscosity or thickness. An SAE (Society of Automotive Engineers) number of 10, printed on the label of the oil container, means thinner oil than one marked as SAE 30. As a rule, you should stick with the oil recommended by your car manufacturer, found in your car's owner manual, but if your vehicle has a high mileage engine, thicker oil will help protect worn out parts better.
- 3). Check the oil's viscosity range. Some oils are designed for use in places with a relatively stable temperature: SAE 30, for example, is ideal if you drive in weather ranging between 40 and 100 degrees F (4 and 34 C) year round. Other oils can be used for a wider temperature range. Oil designated like SAE 10w-30 (multi-weight), for example, is ideal if your local weather ranges between 10 and 110 degrees F (12 and 38 C) year round.
- 4). Find the oil service rating. This is another important label to pay attention to. The American Petroleum Institute (API) has been designating letter pairs from SA to SJ--and counting--to characterize oil performance. The higher the letter in the alphabet assigned, the better the oil characteristics. SA was the first standardized oil, and it should not be used in automobiles. SJ came out in 1996, and any car that came out that year and previous years, like passenger, vans, light trucks and other vehicles, may use this oil.
- 5). Use synthetic oils. Synthetic oils are made from materials other than crude oil, like vegetable oil. They have excellent characteristics and may offer better engine protection than conventional oils under regular driving conditions, but they are much more expensive too. If you do a lot of hard driving or stop-and-go driving, you should change your oil more frequently, which means using synthetic oil might not be a good investment. Also, if you have a car with a high-mileage engine and internal worn-out parts, using synthetic oil will not make much of a difference for your engine either.
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