Evening everyone first post so hope to get a lot of information in these forums. I have a 01 Cherokee sport with a 4.0 auto with 192000 miles. My factory service manual recommends 5w30 when temps are below 0 and 10w30 "preferred" when above 0. Also mopar recommends API certified oil. Currently I have owned the vehicle for 4 years and have been using 10w30. In the last several oil changes I have been using Castrol GTX 10w30 with 1 quart Lucas oil stabilizer with a citgo oil filter 4670. Some of you might ask why am I going cheap on oil filters. Well I got a great deal on rock auto on 10 filters for about 1.50 a piece on the filter so I am trying it. Every oil change I always but my filters open and inspect but haven't cut open one of these citgo filters yet. So,we will see how they are made in the next 500 miles when my oil is due. My motor is starting to tick a little and haven't figured where it's coming from. I just ordered a stehescope to help me but guessing it is lifters because noise goes away as engine warms up. What I am really looking for is what have other people used for engines like this. I prefer a conventional oil because I just like changing my oil every 3000. I plan on changing my viscosity to 5w30 this winter to help but what's everyone's thought on the Lucas?I've heard pros and cons on this product. I just have been using this product for the last ten years and have no complaints. I just got my new Silverado a oil analysis last month and plan on getting my jeep done the next OC. I look forward to hearing others people advice. Thanks