What a joke. I just realized when doing an intake manifold gasket replacement that the weld that goes around where the oxygen sensor piece was welded on has a tiny leak there. I can see where's it's black where the exhaust gases were leaking out as it stained around the hole. I am going to use red rtv to seal it. I was going to also throw some jb weld around it but I think it will seal for now. I went over the entire pipe again and it doesn't appear to be leaking anywhere else but there was a spot on the opposite side of the circle of the metal piece where it appears it was going to open up so I rtv'ed all around the piece to be on the safe side.

 

That sucks.

 

are those H22A4 headers?

 

That's why DC headers suck, mild steel rusts and the coating flakes over time.