+1
Look around the cap on your "degas bottle", the overflow where you put your coolant in. If there is water or crust around it, pull the heads. If not, and your not blowing white smoke, its up to you.
Here's what I do, as a mechanic. There's alot to say about procedures that mechanics do, especially to those who bash on mechanics saying that we are all out to steal everyones money. Alot of times that is true, I will admit. But there are some of us that are honest and take pride in our work. With that said, even if you think something might be overkill, you also have to remember, even an honest mechanic HAS to overkill some things to save his own hide, if he's going to warranty something. So if I'm going to go to the extent of pulling a cab and do all of this work and spend this much of a customers money, I'm going to surface the heads and check the valves. For their sake, and for mine.
Assuming nothing has been done to your truck in the past, and you want it "bulletproofed", if your going to drive it another 100k, or whatever:
Pull the cab, resurface the heads and have the valves vacuum tested. They will probably check fine, most do. New gaskets, and head studs are a must. Replace the STC fitting on the pump, stand pipes, and oil cooler with ford OEM stuff! When you put injectors back in, seal kits are used. These kits come with all o-rings, including the high pressure oil oring that goes in the top. Alot of mechanics don't bother, and throw them away. NO! This is a very common failure. Insist on these being replaced. According to EPA, I can't really suggest that you delete the egr cooler, but take ftg-05's advice
And when you do, get the kit that comes with the up-pipe. It gets rid of the opening with the flow diverter. And replace the up-pipe on the other side if you want to be overly cautious. These fail somewhat often and make a screeching sound when building boost. Very obnoxious. When going back together, use a new turbo bolt down kit from ford, comes with new drain o-rings. Flush the cooling system well, including pulling the block drains. Refill with ford gold or as ftg suggested, the cat equivalent (again, I'm no chemist, I don't know). And use distilled water to mix. Throw in a blue fuel pressure regulator spring, new filters (don't forget the 2nd fuel filter on the frame rail), and your pretty bullet proof. Hope I didn't forget something. Its alot different trying to type everthing versus having the truck sitting here to look at, lol.
You can do more, you can do less. Depending on how bullet proof you want to be, and how much you want to spend. Its all a gambling game. Some people go a quarter million miles and have zero problems. Some people go 40k and the truck falls apart. But more often than not, I explain all of this to a customer that has had just one of these components fail, and they opt to replace the single component, and come back in 6 months and another has failed, then another, etc. Much more expensive to do it one at a time.
If your buds with the mechanic, that helps. He can help on the labor. Example, the turbo is already off, its a half hour or so to pull it apart and clean the carbon out of it if he was so inclined to do so. And 5 minutes to pull the exhaust back pressure sensor off and blow the carbon out of the tube that feeds it. Little things like that which will help your truck keep running better, longer. And if its someone that cares enough, he'll use the right parts the first time. If they don't know what they are doing, bolts will be lost and left out, brackets misplaced, wires misrouted and later chafed, etc.
Another thing to look at before you head off on a long journey with your newly bulletproofed truck. Have the mechanic look at the FICM voltage. You'll have 2 readings for battery voltage, and one that will be around 48 volts. 47 or 47.5 on a hard acceleration is ok, but anything below 47, the FICM is going out. Its going to leave you stranded soon, just like any of the other mods I mentioned above. So technically, its just as important to have checked as all the rest.
Lastly, have the calibration checked in your PCM. If its not withing the last year or so, have it reflashed. It deals with a couple of common problems, including cycling the turbo vanes to keep carbon clear, MAF/MAP/EBP correlation issues, and some issues with refueling with the key on causing a sticky fuel gauge. Some independent shops can do this, which is somewhat rare in my parts. I'm one of the few. Otherwise a dealership.
Sorry, I haven't re-read. This is probably very long. I'm good at rambling. But hey, at least I'm thorough. And I bet after all of this, I've still left some out. Haha
