The Audi 4.2L V8 is a great performing engine that has the ability to reach remarkable mileage with proper maintenance practices. Keep your cooling system in proper order with the Mishimoto Audi S8 Quattro Racing Thermostat engineered for improved cooling efficiency and extended reliability. Mishimoto racing thermostats promote greater cooling efficiency by significantly decreasing high engine temperatures. Once the engine is fully warmed up, the Mishimoto low-temperature racing thermostat opens at a lower temperature (160°F) compared to standard thermostats (189°F). This allows coolant to flow through the engine sooner, thus reducing and maintaining cooler engine temperatures. Mishimoto Audi thermostats are digitally calibrated, utilize high-quality wax to ensure precise and consistent opening temperatures, and include a gasket for seamless, leak-free installation. Trust the Mishimoto racing thermostat to keep your S8 cool on the highway, back roads, or track. As with all our products, this racing thermostat includes the Mishimoto Lifetime Warranty