The whole engine oil thing seems kind of odd to me. I spent many years working directly with Dodge/Chrysler/Jeep engineering performing vehicle tests and evaluations and never heard anything about the 4.0L needing some very special oil. Also being in an off-road club for going on 12 years I personally know at least 20 people with 4.0L powered Jeep vehicles, and my mom had two 4.0L Grand Cherokees, and none of them have used "special" Mopar oil or additives and many have high mileage. I know at least one guy has over 130k on his 4.0L TJ using off-the-shelf oil. The woman who bought one of the Grands off of my mom is local and I see her in it all the time. Not sure how many miles but think it's around 6-7 years old now so sure the mileage is getting up there.
I know those ingredients are very important during initial break-in (i.e. if you just rebuilt the engine) and there are specific oils and additives available for this....but prior to this post I have never, ever heard of the 4.0L requiring this.
I know those ingredients are very important during initial break-in (i.e. if you just rebuilt the engine) and there are specific oils and additives available for this....but prior to this post I have never, ever heard of the 4.0L requiring this.
