yes have looked under vavle cover before and after, and was suggested by other jeepers that the rotella 15-40 was a good oil for these flat tappet cam motors. i also used it to help with consumption, manual recommended probably wouldn't help, i'm not against it but in my case i feel there are...
i can try a high mialage, i was too looking at pen defy, any feedback on that? the reason to look at the 15-40 convetional oil or the T6 syn is they are only 12 bucks a gallon at my wal-mart.
Hey guys i have a 90 jeep cherokee 4.0 with 208,000 on the clock. when i bought it i changed the oil with rotella 15-40 and a wix. A lil thick for winter but really don't reach much lower then 20 degrees, which i believe 15-40 is good till 10 degrees. i drive it fairly easy in town but when i'm...