What's the difference between an oil that's rated CI-4+ and CJ-4. I know the CJ-4 oil is for the 2007 emissions engines. So is there a benefit to running one or the other in a pre-2007 engine?

Schmitty

 

As I understand it, the CJ-4 oil is the better oil for diesels burning ULSD fuel.

 

These ratings are performance specifications. CJ4 is a higher letter so its a more advanced spec, and its backwards compatible, so yes its better. Will it protect your engine better? The difference is likely unmeasurable.

 

It supposedly has better coking inhibitors also.

 

here is some good info i found:

CJ-4, Introduced in 2006. For high-speed, four-stroke engines designed to meet 2007 model year on-highway exhaust emission standards. CJ-4 oils are compounded for use in all applications with diesel fuels ranging in sulfur content up to 500 ppm (0.05% by weight). However, use of these oils with greater than 15 ppm (0.0015% by weight) sulfur fuel may impact exhaust aftertreatment system durability and/or oil drain
interval. CJ-4 oils are effective at sustaining emission control system durability where particulate filters and other advanced aftertreatment systems are used. Optimum protection is provided for control of catalyst poisoning, particulate filter blocking, engine wear, piston deposits, low- and high-temperature stability, soot
handling properties, oxidative thickening, foaming, and viscosity loss due to shear. API CJ-4 oils exceed the performance criteria of API CI-4 with CI-4 PLUS, CI-4, CH-4, CG-4 and CF-4 and can effectively lubricateengines calling for those API Service Categories. When using CJ-4 oil with higher than 15 ppm sulfur fuel, consult the engine manufacturer for service changes.

the oil is meant to be used with 15 ppm sulfur fuel and if you use 500 ppm sulfur fuel you will shorten your drain intervals, API CJ-4 oils are formulated for improved wear protection, deposit and oil consumption control, soot-related viscosity control, prevention of viscosity loss from shearing, used oil low-temperature pumpability, and protection from thermal and oxidative breakdown when compared to previous API performance categories. As always, users should seek guidance from their engine or vehicle manufacturer regarding specific service recommendations.

 

i suggest if you have lsd fuel in your area use the ci-4 plus oil, if you have the ulsd fuel in your area use the cj-4 spec oil this should help you out.

 

If it hasn't already, the cj-4 oil will surplant the ci-4+ oil altogether

 

98% of the gas stations in my neck of the woods have the ulsd now there are 1-2 local places that still carry the lsd fuel but their stock is dwindling as its being fazed out now.