A 2004 Ford F-150 with a 4.6-liter engine takes six quarts of oil, while the same model with a 5.4-liter engine requires 7 quarts. Most vehicle manufacturers recommend changing engine oil every 3,000 to 5,000 miles, and the right engine oil is critical to a vehicle's performance.
Oil lubricates movable engine components to keep them from scraping together and wearing out quickly. It also prevents the engine from overheating. Oil needs to be changed regularly. When it becomes dirty, it does not coat the engine parts properly, and they are more likely to grind together. The owner's manual indicates the oil weight that should be used.