Which characteristic is NOT a feature of synthetic lubricants?

Synthetic lubricants are known for their advanced formulation and performance benefits compared to conventional oils. One of the key characteristics of synthetic lubricants is their better thermal stability, which allows them to maintain performance over a wide temperature range without breaking down. This characteristic is particularly important in environments with extreme temperatures, where conventional mineral oils may fail.

Additionally, synthetic lubricants are specially engineered to perform exceptionally well in extreme conditions, such as high-pressure or high-temperature environments. This is due to their ability to resist oxidation and degradation more effectively than traditional lubricants, thereby prolonging equipment life and enhancing overall performance.

Lower volatility is another feature of synthetic lubricants, which means they do not evaporate as easily as conventional oils, resulting in less consumption and a longer service life. This characteristic also contributes to maintaining a more stable lubricating film in high-temperature situations.

In contrast, while it is true that synthetic lubricants generally have a higher cost than their mineral counterparts due to their complex manufacturing process and raw materials, this characteristic is not a performance feature like the others listed. Instead, it reflects the economic aspect of selecting lubricants. Thus, the characteristic that does not align with the functional attributes of synthetic lubricants is indeed their higher cost.