I have the top of my intake manifold off for a repair, and its pretty dirty. Is this normal? The truck has over 200K miles on it. I know that their is emissions stuff like pcv valve and such, is their also exhaust gas that enters the intake on the 5.7 vortecs?
i just want to make sure I am doing all necessary repairs while I have so much taken apart on this motor right now. Thank you.


In this photo I was just pointing at a clean spot. It is because this fuel pressure regulator is bad. I have the manifold off to replace the fuel injector spider. You can see how dirty it is. I think there is even a little oil in some spots.

 

I think if I had it torn down that far, I would just remove the intake entirely and clean it really good, and replace the intake manifold gaskets.

I've replaced the intake manifold gasket on my 1996 C1500 Vortec engine twice over the years. That first time I think I tinkered with it a month or more, out in the garage. Second time I think it was a 3 hour job. Anyway, I never took the intake itself apart, but am nor surprised it is that dirty inside the intake for a truck with 200k miles on it. I imagine mine looks the same (203k miles).