Castrol, QT, 10W40 GTX High Mileage Motor Oil, Utilizes Special Base Oils To Provide Superior Protection Against Oil Burn Off, Contains Seal Conditioners That Provide Added Level Of Protection & Help Reduce Leakage, Contains Proprietary Additives That Provide Superior Protection From Wear & Harmful Deposits In Higher Mileage Engines, Reduced Deposit Formation To Minimize Compression Loss & Maximize Compression Loss & Maximize Engine Performance.