Choosing the right oil for your vehicle, climate

The oil that goes into modern engines has become as unique as the vehicles themselves. What you choose can affect wear and tear as well as engine performance.

Modern oil mixtures use a man-made fluid, or synthetic blend, to keep your vehicle operating at peak performance–even during the hottest dog days of summer.

How do you choose what is best for your vehicle?

“Traditional motor oil is 80 percent from crude oil, or ‘basic stock,’” said George Zhang, a chemist at Valvoline. “The other 20 percent or so includes additives manufacturers include to enhance stability of the final product.”

In contrast, synthetic oil is derived from petroleum and goes through a manufacturing process to alter its carbon chemistry. The result: A lightweight, durable compound that performs well in extreme driving conditions.

The roots of synthetic oil can be traced to World War II. In Germany, chemists invented processes to extend their dwindling stocks of crude oil. About the same time, US engineers invented an oil derivative that allowed fighter planes to perform better in frigid climates.

“Traditional oil can almost become solid in a vehicle exposed to extreme cold temperatures,” Zhang said. “In the worst cases, hardened oil can even prevent the car from starting.”

The unique formulation of synthetic oil prevents it from thickening. It also prevents carbon molecules from breaking down from heat generated by high performance engines.

“Synthetic oil is less dense, and it burns less, especially in older vehicles,” Zhang said. “In that way synthetic oils are more environmentally friendly,” he said.

Manufacturing processes have improved synthetic oil and the way it interacts with vehicle engines, Zhang said. Early generations of synthetic oil sometimes caused rubber seals to become brittle, he added. Today, oil refining processes have eliminated compounds that adversely affected seals or other engine components.

Another benefit is what Zhang called “pumpability.”

"Synthetic oil pumps through the engine better, and that means you have lubrication everywhere it needs to be,” he said. “But the choice of which oil to choose for your vehicle isn’t just between traditional and synthetic motor oil.”

Oil manufacturers have blended synthetic and traditional motor oils for specific uses. As an example, they are designed to handle to extreme heat created by high performance engines.

Do synthetic oils extend the interval between oil changes?

Not necessarily, Zhang said. Synthetic oil may need to be exchanged just as frequently as traditional motor oil.

“We always recommend following manufacturer guidelines for oil change intervals,”

Zhang said.

Moreover, conventional motor oil may offer better properties for vehicles with high mileage. The thicker consistency from basic crude helps reduce seepage from aging oil seals and engine parts.

Zhang had several tips for choosing and using motor oil:

• Check your owner’s manual for the proper type of oil. Today’s vehicles may require oil designed specifically for the particular model and make.
• Consider synthetic oil for high performance engines. It can tolerate the extreme heat and speed of engine parts.
• Select your motor oil based on your driving conditions. Do you live in an extreme cold or hot environment? The thinner viscosity from synthetic oil helps engines turn over and its chemical composition is designed for high temperatures.
• Ask your service advisor about using conventional motor oil if you have a high mileage vehicle. It has thicker viscosity and is less like to leak through aging motor seals.
• Look into using synthetic oil for improvements in gas mileage. It has less friction with engine parts and provides improved performance.
• How and where you drive your vehicle make a difference in the type of oil best suited to your vehicle.

“Switching between the two types does not damage your vehicle engine,” Zhang said. “You can use either synthetic oil or conventional oil depending on your driving conditions.”