Designed to protect today's sophisticated engines and meet the performance needs of GM vehicles (dexos1 Gen 3), Quaker State High Mileage Full Synthetic 5W-30 motor oil is the best high mileage motor oil of the Quaker State family of products. Specially formulated to provide optimal wear protection for many more miles to come, this motor oil conditions the seals in your aging engine to prevent leaks and reduce oil burn-offs. You'll also get all the benefits of a full synthetic motor oil — like reducing friction to maximize horsepower, protecting against the formulation of sludge and harmful deposits, and providing improved fuel economy.