oil weight/type Duramax 6.6 Silverado

[grassy]

Need to know what Chevy recommends for oil wieght and type for my 04' 3500 Silverado Duramax Diesel. Owners manual is generic wthout mention for this truck..
Thanks

[Duramaster]

Up until recently my dealer was using Delo 400 15W40 LE oil. We have now changed suppliers and are now using a Mobil Delvac 15W40 LE of some type. Regardless, neither one is synthetic. :)

[DmaxMaverick]

The standard recommendation is 15w-40, CI-4 oil (the API rating is as important as the grade). You can use 5w-40, or 0w-30 in extreme cold climates. Synthetic or dino.

You should have received the Diesel supplement with your owner's manual. If not, you can get one from your dealer, Helms, or online.