3 or 3K for LD (5.9L, 6.7L, 6.9L, ect)
6 or 6K for MD (DT466, DT530, ect)
8 or 8K for HD (cat 3406, 400 cummins ect)

thats just what I like to do thats running Delo 400 LE 15W40

syns I bump everything up 2500 miles

 

I've got boxes of rockers and pivots ruined by a lack of ZDDP. Mainly CR Trucks. I'm impressed with where this thread has gone. It's full of correct and useful information!

guys!

 

As for zddp, those levels have gone down with the new CJ-4 rated oils, but they are still good oils and provide the needed protection. Some like to stick with the older oils. The zinc levels were typically above 1300 and some oils were over 1500.

As for straight weight oil, it can be run. It's just gone by the wayside because the multi-viscosity oils offer a lot more flexibility. If I lived in Southern Florida and never planned on driving anywhere else, I'd run it no problem. The straight weights can withstand more as they don't have/need any viscosity index improvers. These are typically found in the multi-grades to make them multi but they are suseptible to shearing, but a good quality oil should have no problems for its intended interval.

Lastly on the additives...if you're running a good quality oil, there really is no need. the real problems is you don't really know how that additive may be affecting the chemistry of oil??

 

ideally 3000 miles, usually like 5000 miles

 

and the oil man has spoken thanks Heath!