Description Mobil 1 High Mileage motor oil provides unsurpassed wear protection for engines with over 75,000 miles. This advanced full synthetic lubricant features a proprietary blend of high performance synthetic base oils that deliver up to 500,000 miles of proven protection. The oil has a higher base oil viscosity to help reduce leaks and provide better high-temperature protection (except 0W-20)âplus a boosted level of seal conditioner to protect engine seals and guard against leaks. Mobil 1 High Mileage motor oil can also help reduce sludge deposits that are due to less-than-adequate maintenance practices. Choose the oil weight recommended for your application.