I had to pull my intake manifold and now that I'm trying to put it back on I need to replace the o-ring that goes on the coolant pipe connecting to the bottom center on the intake mani. My Haynes manual makes no mention of this pipe.

It runs from the bottom center of the intake manifold back around the engine and connects to one of the hoses going to the heater core. I just need to know the name of the part I need in order to seal the junction at the pipe and the manifold. It is a small washer or o-ring. The old one is falling to pieces and the head gasket set I got doesn't have a replacement in it.

Any help would be greatly appreciated.