09 Duramax?

[HighVoltage]

I use Amsoil 5W-40 in my 08' D-max. Can never go wrong using Amsoil and it protects better than all the above mentioned oils. I know I spent the extra money for the diesel so that's why I use the best to keep it going. Oh ya and it's made in the USA!

 

[bbslider001]

Um, HighVoltage is it? Amsoil does NOT protect better. It may last a little longer....MAYBE, but does not protect better than nay other HDEO. If you provide numbers to prove this, then be my guest, but to just state that because you read it or heard it somewhere or it "feels good"....just isn't true. Many UOA's on here show that many oils, dino in fact, protect just as well, if not BETTER than Amsoil....and yes, I am a former Amsoil junkie, so I know of which I speak.

 

[Jim 5]

Originally Posted By: HighVoltage
.......Can never go wrong using Amsoil and it protects better than all the above mentioned oils. ......


There's a number of respected and long-standing Amsoil dealers on this site. You wouldn't hear them say that.

Spend some time in the UOA section and you'll change your tune. Extremes of temperature and OCI are where synthetics add value.

Also, what cowhorse said.