Remove the intake manifold and have fun manually removing the pieces. You need to go back to the dealer to get the steel version of that coolant nipple. The steel was offered on GM cars of the same year. The truck nipple is soft and brittle pot metal. It ain't worth nothing. You should have soaked the thing in PBLaster and then tried to remove it. And as for the above comment about the weep hole being used as a fail safe to alert you that coolant is leaking into the block is incorrect. The weep hole alerts you to the fact that the seal which prevents coolant from escaping out of the water pump and into the water pump BEARINGS has failed. The longer you drive with the weeping pump, the more likely the water pump may seize up because all the lubrication for its bearings is being washed away. Sorry about your nipple breaking off, sometimes it's just the luck of the draw. -Chris