What element of high-mileage engine oil helps prevent leaks?

High-mileage engine oils are specifically formulated with special additives designed to cater to the needs of engines that have accumulated significant wear and tear over time. These additives often include seal conditioners or agents that help rejuvenate and expand rubber seals and gaskets, which can become hard and brittle in older engines. By improving the flexibility and sealing capability of these components, high-mileage oil aims to prevent leaks that are more common in aging engines.

In contrast, while high viscosity properties can contribute to how oil behaves under pressure and help with wear protection, they do not directly address the leakage issue. Standard detergent components primarily focus on keeping the engine clean and preventing sludge buildup, rather than sealing capabilities. Reduced friction characteristics are beneficial for enhancing engine efficiency but do not play a role in preventing leaks from old seals and gaskets. Thus, special additives formulated for older engines are crucial for addressing the specific challenges posed by high-mileage conditions.