The 6.0L Ford motor has a bad reputation. If you start to tell someone that you own one, they'll usually say "I'm Sorry" before you can finish the sentance. In reality it is actually a pretty good motor if you do some preventative work. If you just toss a programmer on it to increase hp/torque, you are going to have problems. There is a good writup on the Powerstroke Forum that describes the problem:
"Ford Gold Coolant contains silicates, which under the heat and stress of operation break down. The first place this gel gets to gather is in the internals of the stock oil cooler, in the narrow passages of the coolant/oil heat exchanger. This build up prevents proper coolant flow through the oil cooler, and deprives the EGR cooler of coolant. The welds in the EGR cooler rupture from overheating, and allow for coolant to flow into the intake manifold and into the cylinders. The coolant then vaporizes upon compression, and the resulting pressure is relived through the head gaskets, stretching the stock headbolts, and degas bottle cap."
In addition to the common head gasket failure there are some other problems Ford identified and came up with revised parts for. The HPOP (high presure oil pump) has a 2 piece fitting that is held together by a plastic fitting. It's common for this to break and then the truck won't start. Ford also has a revised oil feed and oil return line to the turbo. They revised their fuel delivery system so that the regulator has a stronger spring to increase fuel pressue. They also started using banjo bolts with 2 holes instead of one to increase fuel flow. My truck had 136k miles on it and still drove fine. However to keep it that way I decided to do some preventative work. While I was at it I figured I should also do a bigger exhaust and programmer to get me some more power:)
Basically you start by pulling the cab. This is the way the dealer will do a head gasket job. Then strip the motor down to the block. Then you get the heads checked/milled and reinstall everything using newer revised parts where needed. This is the list of what I did.
The factory turbo in the 6.0 is a VGT turbo. That means it has vanes that will open and close so that you can get the spool benefits of a smaller turbo housing and the WOT benefits of a bigger housing turbo. These vanes can get clogged up, especially if the truck is babied and the vanes don't travel through their full range of motion often. My vanes were frozen up pretty good. I was able to clean everything up with a file/wirebrush so that they work properly now. You also want to inspect the pin hole that the solenoid pushes on. It's common for the holes to elongate on higher mileage engines. Mine was fine.
Now my truck came from Virginia and I don't drive it through the winter, so it is fairly clean. However I still had to replace a cab corner for some reason. It's just a poor design. So to replace the cab corner I had to pull the bed. I was going to do the cab corner when the cab was off, but with the cab on the lift I couldn't open the rear door. When I had the bed off I noticed that there was a lot of rust starting on the inside of my rear wheel wells. This rust wasn't visible on the outside of the truck yet. It's really an awful design. Ford installed an inner metal fender liner above the wheel well arch. This liner creates a cavity so that dirt/mud can settle on the inside of the rear wheel wells and rust out. I caught mine just in time. I drilled the spot welds and removed the inner liners. I then sandblasted the rust away and sealed it up. It's a little hard to explain, so I created a few Youtube videos on it below: