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Thanks, for the reply. It seems that PYB, DEFY and Rotella are the top three brands recomended for the 4.0 engine. For me Rotella T5 is easy to come by and sounds like 10w-30w is what I need to run instead of 5w-30w.

Based on uoa's does anyone know which oil brand's and their weight's produce the best wear numbers for the 4.0 jeep engine with 110,000 miles. Based on the post here it seems the 4.0 jeep engine has a lot of iron showing up in their uoa's. I am mainly looking at blends or dino oils with a 3000...

Hey, thanks to everyone for the quick responses. It sounds like I have five or six good quality oils to choose from. Seems like the 4.0 gets a lot or write ups on this site! Thanks again.

Thanks tomcat27

I have a 2001 jeep wrangler 4.0 with 110,000 miles. I bought it used so I have no idea what kind of oil the previous owner used. I do know the valve train looked spotless when I replaced the valve cover gasket. Anyhow I have been looking around on this site trying to figure out what brand of oil...