2005 Silverado DSL OCI question

[Ls_Dx]

My brother out of state has been brainstorming on the OCI on his 05chev 2500 HD (he has got the same mind set as us other BITOG'ers and wants to take care of his pickup)

I told him to check his owners manual- It says to refer to the engine oil service light. It says he has 50% oil life left.
he has 5k on his current OCI. Last time he changed it he used 15w40 mystic syn blend. He lives in texas and it is starting to warm up there. He uses it for commuting, and towing a 5th wheel horse trailer.

what should I recommend for him OCI.. I know nothing about maintaining a Diesel... thanks

 

[Bambam]

Duramax engines have proven to be very easy on oil,without oil analysis I would go with a 7500 mile oci.

 

[bbslider001]

Or even 10k OCI. I have been using a conventional oil after having used Amsoil for awhile and been getting good results, Just use a good conventional (Rotella, Delvac, Delo, John Deere) and a good filter such as Wix, Mobil 1, etc...and he'll do fine.

 

[dnewton3]

2X the above.

7.5k miles is a conservative mileage. 10k miles has been proven quite reasonable in many used oil analysis.