Reading these posts scare me as I've always ran synthetics, in all my used vehicles but from what I can see even though the 4.0's are rock solid if you run the i.e. copper plugs, conventional oil, and try to stay away from all the newer age synthetic fluids then they last forever. So with my first oil change coming I was going to use 3 qt. 10w-40 Mobil One High Mileage and 3 qt. 5w-40 mobil one diesel oil since it has more zddp and zinc which supposedly our 4.0's like a lot seeing they have flat tappet cams. What do you guys think? Run all 6 qts of 5w-40 Mobil turbo diesel due to the 1200 vs. 800 gasoline oil ZDDP restrictions? Or run a High Mileage oil like the 10w-40 Mobil One. Or blend the two as I was...It has 10w-40 GTX in it now which I have seen to be a good cheap oil, but I like the Mobil One stuff. I'd really like to try Amsoil just kinda taken aback by the price plus the shipping cost to send me some. If I did get Amsoil I'd go ahead and get tranny, and diff fluid at once so the shipping would only be a one time thing, and get some filters too.
1995 ZJ 2" BB, 31x10.50/15 KM2's painted stockers, B&M RV shift kit, 18k cooler, Extended Energy sway bar links.
Last edited by RhinofiedZJ; 01-15-2010 at 01:41 PM..
Reason: mispell and addition