Mobil 1 High Mileage oils are designed to maximize engine performance and help extend the engine life of vehicles with over 75,000 miles. The Mobil 1 High Mileage oils are made with a proprietary blend of high performance synthetic base stocks fortified with an additive system designed especially for higher mileage vehicles. Mobil 1 High Mileage oils are especially recommended for high mileage vehicles - even those that have used lower quality conventional oils. As your engine ages, seals deteriorate, oil burn-off increases and sludge can build-up, which can all result in a decrease in engine performance and, ultimately, reduce engine life. Mobil 1 High Mileage 10W-40 motor oil is designed to maximize engine performance and help extend engine life. Mobil 1 High Mileage is designed especially for engines where conventional oil has been used, and where these conditions have been experienced: severe service, extended oil drains, poor maintenance, or multiple owners. For engines where heavy deposits and sludging exist, Mobil 1 recommends initial oil change intervals of 3,000 miles as cleanup progresses. Mobil 1 High Mileage oils are suitable for all types of severe driving applications including high speed highway and stop-and-go city driving.