Top brands of motor oil as used by Pep Boys, a national chain of auto repair and supplies shop, include Penzoil, Castrol, Mobil 1, Valvoline, Royal Purple, Peak, Quaker State, Shell Rotella, Motor Craft and Mobil Super, as of 2014. Several types of oils exist, each catering to a different type of vehicle or engine.
The type of oil chosen for a vehicle depends on the vehicle and the needs of the driver. Motor oils are premium conventional oil, full synthetic oil, synthetic blend oil and higher-mileage oil. Premium conventional oil is the standard for most new vehicles. Full synthetic oils are reserved for higher-tech engines such as those found in the Chevy Corvette or Mercedes-Benz. Full synthetic oils have passed more stringent tests and perform higher in areas such as viscosity.
Synthetic blend oils are mixtures of synthetic and organic oils. They are designed for vehicles that accommodate heavier loads and higher temperatures. They are good choices for SUVs and large vehicles. Higher-mileage oils accommodate vehicles with greater number of miles than average. A number of additives are included in motor oils, each with a different function. Additives serve to aid in viscosity or function as detergents, dispersants or foam inhibitors, or they prevent rust or contain anti-wear properties.