Synthetic motor oil will not thicken during cold temperatures which will make engine starting and oil pressure buildup better. Synthetic motor oil does not evaporate as quickly. This reduces the risk of oil sludge and replacing oil as often. With the more constant viscosity, there will be an improved fuel economy.Click to see full answer. Considering this, what are the advantages of using synthetic oil? The benefits of synthetic oil vs conventional oil: Increased engine protection and wear from lower friction. Longer intervals between oil changes. Reduced engine drag from greater resistance to thickening. Oil effectiveness/quality is more predictable and uniform.Also Know, what’s bad about synthetic oil? In addition, synthetics resist viscosity changes at extremely high temperatures that can break down or evaporate molecules in conventional oil. When this kind of deterioration happens, metal-on-metal contact may occur, causing permanent damage to the engine. Hereof, what are the pros and cons of synthetic oil? Pros and Cons of Synthetic Oil Molecular consistency. It is one of the major benefits of this type of oil. Temperature resistant. They perform well under high temperature. More robust. Synthetic oil for cars is stronger than a conventional lubricant. Expensive. Might be Risky for Older Cars. Does synthetic oil add horsepower?Synthetic oils (right) have molecular shapes and sizes that are identical, reducing the internal friction in the oil. The reduced friction benefits the engine on cold startup, increases fuel economy, and can improve engine torque and horsepower output. In most cases, synthetic oils outperform mineral oils.