Most cars on the road today use multi-grade oil — one that can work efficiently in cold and hot weather. A multi-grade oil is rated by two numbers.
Each engine oil comes with a classification indicating its viscosity, which is its friction or resistance to flow. In a multi-grade oil, the first number indicates how the oil will flow when it is cold. The lower the number, the lighter the oil and the better it will perform at lower temperatures.
During cold starting, only a small amount of oil is present in the upper parts of engines. To lessen the friction when upper engine parts, such as the valve train, pistons, overhead cam and cam bearings, scrub against each other, a lower viscosity allows the oil to reach the components more quickly.
This is typically an oil-based fluid used in a transmission that lubricates and cools the transmission and provides hydraulic pressure to shift gears automatically.
Many vehicles today leave the factory with 5W-30 or 5w-20 engine oil. Vehicle manufacturers recommend them because they are lighter oils that perform well in a range of temperatures and help improve gas mileage.
The simplest and safest way to find out is to check your owner’s manual...or talk to your Family Auto mechanic.
Your vehicle relies on a variety of fluids to operate its brake, steering, transmission, engine cooling and other systems. When these fluids become degraded or are at incorrect levels, damage to other components may occur...so always follow the manufacturer.