Synthetic oil versus conventional mineral oil

Synthetic oil
Synthetic oil
Many newer cars require synthetic oil, as it offers better protection for the engine. The advantage of synthetic oil is that it can withstand higher temperature and can work longer without losing its lubricating qualities. Synthetic oil doesn't get thicker at below-zero temperatures and provides better engine lubrication at a cold start. Using synthetic oil makes perfect sense if you have a low-mileage or turbo engine or often drive under severe conditions such as high temperatures, excessive load or long intervals without an oil change.
However, using synthetic oil in high-mileage engines is not always worth the extra cost. Since synthetic oil is "thinner," a high-mileage engine filled with synthetic oil is more likely to develop leaks or run noisier.