I believe you are talking about that brass looking bolt. Actually it's a plug and it screws into the lower intake manifold.
1997 thru 2003 used the same lower intake manifold. But on the 1997 to 2000 I believe that hole is used for the coolant temp sensor. On the 2001-03 they plugged that hole and used what they call a head temp sensor that screws into the back side of the drivers side head.
Usually you use pipe dope or teflon tape on that bolt and is probably your problem. I never seen one crack?? If it did you might get lucky with JBWeld or something similar as there is coolant flowing through there under 16 psi pressure. I just happen to have a 2001 lower intake from an engine swap job I done.
That chrome pipe with what looks like you got epoxy on it is your fuel rail. It connects the fuel line to your injectors which also slides down and bolts into the lower intake.