Hey I have a 1998 Jeep Cherokee Limited with 4.0 inline 6 motor with 140,000 miles. I got it recently and trying to swap all the fluids in it and just wondering what kind of motor oil would be best to use. I have no clue as to what kind of oil was run in the car before hand. I live about 1 mile from work and don't really drive the vehicle much outside of going to work. Longest drive besides a work commute would be about 20 mins, i will also be off roading the vehicle and its been off-roaded before. I live in PA as it is getting colder outside. also I do have some valve noise nothing major just am not sure if that's something to keep in mind as well or not. I also don't know if it makes sense using a synthetic or standard oil, or non detergent oil.
Thank you
Thank you