I’m sure you’ve heard this before: “Oil is the lifeblood of your engine.” If you don’t choose the correct oil, you could accelerate engine wear and cause a premature failure. The right oil may also help with fuel economy and emissions. So, choosing the right oil for your vehicle is critical to your engine’s durability, efficiency and lifespan.
Regardless of type of vehicle you own, Popular Mechanics Magazine recommends buying oil with a “Starburst” symbol on the package. This icon, explains the magazine, designates that the product has been tested and is certified by the American Petroleum Institute (API). Additionally, the API marks a superior oil with a “donut” symbol, which indicates quality in performance, viscosity and energy conservation.
According to the Merriam-Webster dictionary, viscosity is “The property of resistance to flow in a fluid or semifluid.” Regarding your oil, that’s just a fancy way of saying viscosity a measure of how well the oil flows under different conditions.
Motor oil viscosity is represented in numerical values. This is designated by motor oil grades, which signify the oil’s rating from the Society of Automotive Engineers (SAE). In most climates, there are two parts to viscosity numbers. For example, 5W 30. The first number and letter, 5W, is a representation of how well the oil flows in colder weather. The “W” stands for winter. The lower the number, the better the oil flows in colder temperatures.
The second number, 30, is the measure of oil flow at operating temperature. The normal operating temperature of most engines, according to Cars.com, is 195 to 225 degrees Fahrenheit. Similar to the “W” number, the lower the second number, the easier the oil flows at operating temperature.
In some areas, there may be only one number, such as 30 or 40. You usually find this in warmer climates where a “winter” number would be irrelevant. That said, these numbers are very important. They represent the flow characteristics of the oil under a variety of temperature conditions, which is vital to engine operation.
Typically, this information can be found right on the oil cap of your engine. If it isn’t listed, look in the owner’s manual for your vehicle. Some oil recommendations are based on a chart that shows different temperature ranges where different viscosities can be used.
These are not just recommendations. Engineers go to great lengths to determine which oil is best for their engine so it is important to follow them.
Some people might think it’s OK to put thicker oil into a noisy engine when in fact, this may actually cause more engine damage. The thicker oil can take longer to lubricate the engine during startup. This means that important engine components are functioning without lubricant, thus increasing wear on those components. I do not recommend the use of thicker oil in an engine for any reason.
I prefer to use synthetic oil because it can withstand higher temperatures and doesn’t have to be changed as often as conventional oil. However, it’s not always recommended by the manufacturer. Some engines require the use of synthetic oil, but most don’t. Check your owner’s manual for the specifics on your engine.
So, what’s the difference between conventional oil and synthetic oil?
Most synthetic oils actually use an organic oil base. This means both oils share the same organic starting point — very few synthetic oils are actually ‘true’ synthetics. It’s the refinement of that base oil and the additive package that qualifies it as synthetic.
Some engines require the use of synthetic oil, but most don’t. Check your owner’s manual for the specifics on your engine.
I prefer to use synthetic oil because it can withstand higher temperatures and doesn’t have to be changed as often as conventional oil. But, as long as you use the correct viscosity – and your engine doesn’t require synthetic oil – conventional oil will probably work just fine. So if you’re on a budget, regular, conventional oil (also called “dyno” or organic oil), can get the job done, in my opinion.
If you have a vehicle with more than 60,000 miles on it, you may want to try high-mileage oil. High-mileage oil uses a special additive package that is designed for engines with higher miles. This additive package contains special seal conditioners and other components that help a high-mileage engine run its best.
Choosing the right oil for your car can help it last longer and drive smoother, so keep in mind these tips and get more out of your vehicle.
Originally published April, 2015.