I was given 6 qts of Rotella T4 10W30.CK-4. However, it is not rated for gasoline engines. (No API S rating on bottle). Safe to use in a 98 XJ 4.0 or not?

 

This it? https://shop.sclubricants.com/rotell...prot-10w30-ck4

Plenty of folks use the Rotella T4 and T6 specifically because they have higher zinc and phosphorus content. It meets the previous API S specs, but does not meet the current SN rating because they chose to retain the higher level of phosphorus EP additives. That's a good thing.

 

Looks to be the same except your link has an SN rating. This one has no S rating at all.. See pics

 

Yes they only dropped the SN rating for emissions reasons since it has to much Zinc to meet emissions standards for modern gas engine oils, the oil itself didn't change much in that regard.

 

Thanks guys for the answers.