I got confused every one say sumthing difrint i was gowing to pot 15w40 or 10w40 i live in a vary hot environment aftor all.
all so herd from reddit that sum run rotella t4 15w40 witsh is ment for desol. Sorry for my bad English

 

hot equals 15-40

 

The reason for Rotella diesel oil is that it has higher zinc content which is good for our old flat tappet engines.