JOPLIN, Mo. (KSNF/KODE) — The oil in your car’s engine has an incredibly challenging job.

From lying cold in the bottom of the engine’s oil pan, it needs to surge up to the valve gear at the very top, then flow all the way back down — and that has to happen almost instantly when you start the engine. The oil protects everything inside your engine: bearings, pistons, cylinder walls and all the other parts that move or touch something that does.

Because your oil works hard, it’s important to know when that oil and its filter need to be changed. There was a time when local service stations and oil change franchisees recommended changing your car’s oil and replacing filters every 3,000 miles. That rule of thumb might have come partly from a marketing ploy. No matter — today’s fully synthetic motor oil often lasts two to three times as long as conventional motor oil.

Tabitha Ruhl, Manager of Joplin Transmission and Auto Center, said there are two different time frames when the oil in your vehicle needs to be changed, and it all depends on the oil your car uses.

Conventional or Semi-Synthetic Oil

“All conventional is semisynthetic anyway, but a lot of people don’t recognize that,” Ruhl said. “So, on a semisynthetic, you should change the oil between 3,500 to 5,000 miles, or every four-to-six months, whichever comes first.”

Synthetic Oil

“On a full-synthetic oil change, some manufacturers say that those can go up to 7,500 miles or six months without an oil change. At Joplin Transmission and Auto Center, we always recommend doing them between 5,000 and 10,000 miles, or every six-to-twelve months,” said Ruhl.

Should I Use Synthetic Oil? 

According to Consumer Reports, there are advantages to using synthetic oil, versus semisynthetic or conventional motor oil. Full-synthetic is designed to be more effective at resisting oil breakdown, which makes it last longer than conventional oil. It’s also designed to withstand higher temperatures than conventional oil, which helps keep engines running longer.

In most cases, it’s more economical to use full-synthetic oil in your vehicle. Kelly Blue Book reports that an oil and filter change using conventional/semisynthetic oil will cost between $35 and $75, depending on your area. For synthetic oil, you should expect to pay anywhere from $65 to $125, but you make up some of the cost since synthetic oil lasts longer and has to be changed less frequently.

Since electric cars do not use any oil, almost any car with a gasoline engine can benefit from using synthetic oil, with one exception: It’s not recommended for pre-1990 vehicles or those that specifically require conventional motor oils. It’s best to consult your vehicle’s manual, as some newer models can only take full-synthetic motor oil.