Getting ready to change doser at the turbo

[Meanwhile]

Thanks for your replies!

I'm pretty sure this truck sat for more than a year, everything worked and looked fine until I hooked to a trailer with it and found no right turn signal on the trailer. Long story short, it turned out to be a bad chassis node, a plug and a bad wire in the harness. There was evidence under the dash that someone had been in there checking the brains, there were missing screws and such. I don't believe they found the problems and decided to sell it off. The sensors That I replaced looked ok, no heavy build up.

I believe it was August of last year, I had the overhead done. I asked the guy who did it how that cams looked and was told they're good, he didn't see any issues with them. At the same time the DEF doser and exhaust pipe it's mounted to were replaced. The pipe was cracked and the doser was leaking a little.

The fuel pump head doesn't have red paint on it, possibly swapped out already? I'll get a gasket and check out the plungers and tappets soon. I wanted to have those done anyway for piece of mind. I'm assuming everything else is original since it has red paint on it. The cast pipe next to the turbo, that the fuel doser mounts to has a lot of scale on it. It's bad enough that I'm wondering how much will come off when I take it apart. I have another one of them just in case. I guess I'll order the NOX sensor Monday, I'm guessing that's probably the original one. I took the advice of putting the gear oil in, at normal temp oil pressure sits about 35 pounds. The plastic coolant tank looks fairly new and the air filter looked new when I bought it. I check the crankcase filter every oil change and chance oil at 15,000. I'm not sure if I'm running the mandate or not, I'll have to look into that, how can I find out? A couple shops have told me that unless they did previous work to the truck there's no records of what's been done. I'll have to look into the oil bypass also.