I have a 2006 with a 2.3. I noticed coolant leaking and traced it to a elbow pipe that is pressed into the block on the front lefthand side. It's not a part you can replace, however it is possible to make a repair. To get at it, I needed to remove the intake manifold, however two of the five bolt heads were corroded to the point I could not get a socket on them. Those two heads, had to be ground off. To do that, it's best to remove the FL wheel and fender insert. After I got the manifold off, I would say its truley impossible to compleatly remove the rotted coolant pipe. I decided to chisel it off. After that, I ground out a little of the remains so I could get a 1/4" NPT tap started. With a wrench, I turned the tap in and then simply installed pipe. It's a good idea to replace all the gaskets while the manifold is off, and if the valve cover gaskets haven't been replaced, this is a good time to do that as well. It took me a good eight hours to do this, including the valve cover gaskets, but it saved the truck. It would be heading for the junk yard without doing this. I hope this might help others with the same problem. Brian.

Rotted elbow pipe on the left.

 

Good job