Bar's Products' Rislone Oil Treatment contains viscosity improvers and lubricity additives, and increases oil film thickness to fight metal-to-metal friction and protect against engine wear. It also increases oil pressure for more power and a quieter engine. Rislone Oil Treatment works with all gasoline and diesel engines using conventional, high-mileage and synthetic oil. It performs in both hot and cold weather and can be added to engine oil at any time.