Without various oils and lubricants, no vehicle will go very far. The engine needs motor oil to lubricate and cool the bearings, pistons, rings, cylinders and other moving parts.
The motor oil you use should meet the viscosity and service ratings recommended in your vehicle owner’s manual. Most engines today are factory-filled with 5W-30 because 5W-30 improves cold starting, fuel economy and allows the oil to reach critical upper valvetrain components in overhead cam engines more quickly than heavier viscosity oils. Most vehicle manufacturers also approve 10W-30 for year-round driving. But heavier grades such as 20W-40, 20W-50, straight 30W, etc. are formulated for higher temperatures and loads, and are too thick for cold weather driving. Extremely thin oils such as 5W-20 and even 0W-20 are for very cold weather only. As for choosing a type of oil, there are three basic types: conventional, synthetic and synthetic blends.