Originally Posted By: dnewton3
The 6.0PSD does great on 10w-30. It also does well on 15w-40 in warmer climates (such as GA). As mentioned, the HEUI will either be fed a thinner lube, or it will make one for you.
Data shows that the wear rates are not generally affected by the vis, so if that is your major concern, then either vis would do fine.
Other concerns are not likely to affect you; cold idle romp and such won't be an issue in GA.
I would recommend you run the normal OCI (out to around 7.5k miles) on any CJ-4 lube you prefer. Use a conventional base stock; you will never reap the benefits of syn in regard to starting or wear or OCI.
By far and away, the oil cooler is the origin of nearly every evil facing the 6.0L PSD. Address that first and foremost. Being stock, if you haven't had issues yet, you will eventually. And they get more expensive the more you ignore them.
Awaiting rr1 to chime in here ...
Dave, I always agree with your assessments and the data you show may be correct, but I assure you, they do not apply to the 6.0. They really don't. Even as a 7.3 owner, I found out just how vital the oil is to the injection systems. I am not talking about the rotating assembly, and those parts are not a problem in these motors, but the fuel system gets VERY expensive real quick if not properly treated. I would always say conventional with 5-7k intervals, but not with the 6.0, if you like your pocketbook in the least.