DD is right, most topics like engine oil have been discussed at length a million times
but what about 1,000,001?
Trouble with searching a topic is knowing how to search properly. Try searching "oil analysis" or "favorite oil" or "best oil" and you will get a few really good threads and a bunch of semi-relevant threads. Way more information there than here...
Search function works well if you take the time to play with it.
--Hugh
oh yeah, I use Rotella T 15-40W, change every 3,300 miles. Easy to keep track of changes: 190K, 193,300, 196,600, then 200K