I have a 2003, 5.9L, 4x4, auto, 3500, with about 110,000 miles. I have noticed a significant increase in the diesel oil smell from crank case breather tube. Any idea what the cause and fix for this is?

 

I run shell rotella (rosmella) and it smells for a bit then gos away its probably just the oil your using and will go away mine dos it right after a oil change

 

I've noticed that I smell mine more when the weather gets colder. Just reminds me that I drive a BEAST of a truck....

 

You might try running a short (or) long hose from the draft tube to run the fumes closer to the pavement to help move the vapors further away.
---At the fleet shop where I used to work it was a common practice. I remember 3406 Cats coming in that looked like steam coming out of the hose

I know it helps a little on my 04.

 

x2
Rotella has a very distinct smell, I notice it most for a week or so after an oil change.