hank

I have a F350 2004 6.0 turbo diesel with 30,000 miles and just recently started having the following problems:
1-On and off grinding noises coming from the engine in the morning when I start the truck, then noise disappears.
2- Inside of exhaust pipe covered in heavy black carbon, and right rear lower fender above exhaust covered in carbon.
3- Under normal driving conditions, truck will sometimes blow heavy black smoke from the tailpipe.
4- Dip stick has a diesel fuel smell
5- In the morning there is a slight smell if antifreeze in the cab of the truck when I start truck.
Of course I went back to the dealer and they can't find anything wrong (as per the computer).
If anyone has an idea as to the problem, I would apprecite a response ASAP.