Is Royal Purple 5W-30 okay to run in the 6.0?

 

A lot of people, including myself, run 5w-40. I prefer a little heavier weight (40 over 30) oil due to how these engines shear oil.

 

You have to look at API certification, it must be CI4+ diesel oil for the 6.0. Make sure you look at your manual. Gas engine oil will not cut it. 5w30 is a gas engine oil. The 6.0 works the oil hard, so a CI4+ or CJ4 rated oil, 5000 mile intervals, with proper filters are a must.

 

You want CJ4 rated oil (latest diesel spec and all good oils are now this rating).

15W-40
5W-40

Are the only year-round diesel rated oils available. There is a Motorcraft 10W-30 (I think) that is diesel rated (old spec I think) but can not be used in the summer and when towing (any time of the year) - per Ford's TSB a few years back.

I personally use Rotella-Syn 5W-40 year round and change it every 5,000 miles with a Motorcraft oil filter bought at Walmart for $17.99/ea!!!