Choosing oil with both CJ4 and SN specs

[devarshi84]

What are the pros and cons of using a API CJ4/SN specced oil (I am looking at a 5w30) compared to a normal 5w30 SN oil?

Is it a better or a worse oil for a standard gasoline car?

What makes a CJ4/SN oil better/worse than standard SN oil?

 

[buck91]

Are you talking about using a HDEO instead of PCMO? In that case, you might lose 0.01% mpg since the HDEO is probably not rated ILSAC GF-5.

I have used HDEO quite a bit in one of our vehicles with no issues. Some say it cleans better, some say the additives are specific to diesel soot. I don't know.

 

[Solarent]

Typically a CJ4/SN oil is an HDDEO which means the additive concentrations (mostly dispersants) are much higher. The CJ-4 (and soon to be CK-4) oils have a completely different set of engine test requirements and so the formulating approach is different. A HDDEO will typically have a DI which is 15-20% and a PCMO will be 6-9%. When an HDDEO is dual rated that means it also passes all of the required engine tests for SN - however it does not meet the "Resource conserving" requirements including fuel economy benefits and phosphorus retention. In some cases the limits on Phosphorus are also waived for CJ-4 oils so you may see one with more than 800 ppm phos still claim SN. This is not good for the catalytic converter and has been removed from the CK-4 formula (all CK-4/SN oils will have to have 800ppm phos max.)

The primary role of dual rated HDDEO is for mixed fleet use - where a fleet manager doesn't want to carry 2 oils for each engine type.
I wouldn't say that one is better/worse than the other, they are just different.

 

[devarshi84]

So a dual ch4/an oil will be less fuel efficient and can be disastrous for the catcon.

Is it good for the longetivity of the engine? Is there an advantage for gaoline engines?

 

[Garak]

What type of 5w-30 HDEO are you looking at? Some CJ-4/SN 5w-30 examples are E6, which means low phosphorus, just like a GF-5 lubricant.