I have my LIM out. Piped off the passenger side of the manifold is the heater core pipe. How is that pipe held in? Mine was only held in with blue RTV. I seem to think there should be more than RTV holding it in. If so, what is it? An o-ring?

Are you referring to the end that goes into the block? If so, that end has o-rings on my 95.

I figured it out. The o-ring was so flattened that it literally was smooth to the touch.

I have an o-ring kit and I used one from the kit as a replacement. Fits like a glove now!