What type of oil should I use? How often?
Hello, thank you for writing in. The oil type for your vehicle will be 10w-30. You can verify this in your owner's manual, and at most automotive parts stores where you would commonly purchase oil. The amount of oil you put in will depend on the size of the engine. Most engines in 1999 Wrangler models require 4 quarts, while the larger 4.0-Liter engine will take 6 quarts with a filter (which holds oil and must be compensated for). You will want to change your oil every 3 months, or 3,000 miles. If it becomes soiled prematurely due to extensive use, high temperatures, or a heavy load, you will want to change it sooner.